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b4c522fa IB |
1 | /** |
2 | This module is a submodule of $(MREF std, range). | |
3 | ||
5fee5ec3 IB |
4 | It defines the bidirectional and forward range primitives for arrays: |
5 | $(LREF empty), $(LREF front), $(LREF back), $(LREF popFront), $(LREF popBack) and $(LREF save). | |
6 | ||
b4c522fa | 7 | It provides basic range functionality by defining several templates for testing |
5fee5ec3 | 8 | whether a given object is a range, and what kind of range it is: |
b4c522fa IB |
9 | |
10 | $(SCRIPT inhibitQuickIndex = 1;) | |
5fee5ec3 | 11 | $(DIVC quickindex, |
b4c522fa IB |
12 | $(BOOKTABLE , |
13 | $(TR $(TD $(LREF isInputRange)) | |
5fee5ec3 | 14 | $(TD Tests if something is an $(I input range), defined to be |
b4c522fa | 15 | something from which one can sequentially read data using the |
5fee5ec3 | 16 | primitives `front`, `popFront`, and `empty`. |
b4c522fa IB |
17 | )) |
18 | $(TR $(TD $(LREF isOutputRange)) | |
5fee5ec3 | 19 | $(TD Tests if something is an $(I output range), defined to be |
b4c522fa IB |
20 | something to which one can sequentially write data using the |
21 | $(LREF put) primitive. | |
22 | )) | |
23 | $(TR $(TD $(LREF isForwardRange)) | |
5fee5ec3 IB |
24 | $(TD Tests if something is a $(I forward range), defined to be an |
25 | input range with the additional capability that one can save one's | |
26 | current position with the `save` primitive, thus allowing one to | |
27 | iterate over the same range multiple times. | |
b4c522fa IB |
28 | )) |
29 | $(TR $(TD $(LREF isBidirectionalRange)) | |
5fee5ec3 IB |
30 | $(TD Tests if something is a $(I bidirectional range), that is, a |
31 | forward range that allows reverse traversal using the primitives $(D | |
32 | back) and `popBack`. | |
b4c522fa IB |
33 | )) |
34 | $(TR $(TD $(LREF isRandomAccessRange)) | |
5fee5ec3 IB |
35 | $(TD Tests if something is a $(I random access range), which is a |
36 | bidirectional range that also supports the array subscripting | |
37 | operation via the primitive `opIndex`. | |
b4c522fa | 38 | )) |
5fee5ec3 | 39 | )) |
b4c522fa | 40 | |
5fee5ec3 | 41 | It also provides number of templates that test for various range capabilities: |
b4c522fa IB |
42 | |
43 | $(BOOKTABLE , | |
44 | $(TR $(TD $(LREF hasMobileElements)) | |
5fee5ec3 IB |
45 | $(TD Tests if a given range's elements can be moved around using the |
46 | primitives `moveFront`, `moveBack`, or `moveAt`. | |
b4c522fa IB |
47 | )) |
48 | $(TR $(TD $(LREF ElementType)) | |
5fee5ec3 | 49 | $(TD Returns the element type of a given range. |
b4c522fa IB |
50 | )) |
51 | $(TR $(TD $(LREF ElementEncodingType)) | |
5fee5ec3 | 52 | $(TD Returns the encoding element type of a given range. |
b4c522fa IB |
53 | )) |
54 | $(TR $(TD $(LREF hasSwappableElements)) | |
5fee5ec3 | 55 | $(TD Tests if a range is a forward range with swappable elements. |
b4c522fa IB |
56 | )) |
57 | $(TR $(TD $(LREF hasAssignableElements)) | |
5fee5ec3 | 58 | $(TD Tests if a range is a forward range with mutable elements. |
b4c522fa IB |
59 | )) |
60 | $(TR $(TD $(LREF hasLvalueElements)) | |
5fee5ec3 | 61 | $(TD Tests if a range is a forward range with elements that can be |
b4c522fa IB |
62 | passed by reference and have their address taken. |
63 | )) | |
64 | $(TR $(TD $(LREF hasLength)) | |
5fee5ec3 | 65 | $(TD Tests if a given range has the `length` attribute. |
b4c522fa IB |
66 | )) |
67 | $(TR $(TD $(LREF isInfinite)) | |
5fee5ec3 | 68 | $(TD Tests if a given range is an $(I infinite range). |
b4c522fa IB |
69 | )) |
70 | $(TR $(TD $(LREF hasSlicing)) | |
5fee5ec3 | 71 | $(TD Tests if a given range supports the array slicing operation $(D |
b4c522fa IB |
72 | R[x .. y]). |
73 | )) | |
74 | ) | |
75 | ||
76 | Finally, it includes some convenience functions for manipulating ranges: | |
77 | ||
78 | $(BOOKTABLE , | |
79 | $(TR $(TD $(LREF popFrontN)) | |
5fee5ec3 | 80 | $(TD Advances a given range by up to $(I n) elements. |
b4c522fa IB |
81 | )) |
82 | $(TR $(TD $(LREF popBackN)) | |
5fee5ec3 | 83 | $(TD Advances a given bidirectional range from the right by up to |
b4c522fa IB |
84 | $(I n) elements. |
85 | )) | |
86 | $(TR $(TD $(LREF popFrontExactly)) | |
5fee5ec3 | 87 | $(TD Advances a given range by up exactly $(I n) elements. |
b4c522fa IB |
88 | )) |
89 | $(TR $(TD $(LREF popBackExactly)) | |
5fee5ec3 | 90 | $(TD Advances a given bidirectional range from the right by exactly |
b4c522fa IB |
91 | $(I n) elements. |
92 | )) | |
93 | $(TR $(TD $(LREF moveFront)) | |
5fee5ec3 | 94 | $(TD Removes the front element of a range. |
b4c522fa IB |
95 | )) |
96 | $(TR $(TD $(LREF moveBack)) | |
5fee5ec3 | 97 | $(TD Removes the back element of a bidirectional range. |
b4c522fa IB |
98 | )) |
99 | $(TR $(TD $(LREF moveAt)) | |
5fee5ec3 | 100 | $(TD Removes the $(I i)'th element of a random-access range. |
b4c522fa IB |
101 | )) |
102 | $(TR $(TD $(LREF walkLength)) | |
5fee5ec3 | 103 | $(TD Computes the length of any range in O(n) time. |
b4c522fa IB |
104 | )) |
105 | $(TR $(TD $(LREF put)) | |
5fee5ec3 | 106 | $(TD Outputs element `e` to a range. |
b4c522fa IB |
107 | )) |
108 | ) | |
109 | ||
5fee5ec3 | 110 | Source: $(PHOBOSSRC std/range/primitives.d) |
b4c522fa IB |
111 | |
112 | License: $(HTTP boost.org/LICENSE_1_0.txt, Boost License 1.0). | |
113 | ||
5fee5ec3 IB |
114 | Authors: $(HTTP erdani.com, Andrei Alexandrescu), David Simcha, and |
115 | $(HTTP jmdavisprog.com, Jonathan M Davis). Credit for some of the ideas | |
116 | in building this module goes to | |
117 | $(HTTP fantascienza.net/leonardo/so/, Leonardo Maffi). | |
b4c522fa IB |
118 | */ |
119 | module std.range.primitives; | |
120 | ||
121 | import std.traits; | |
122 | ||
123 | /** | |
5fee5ec3 IB |
124 | Returns `true` if `R` is an input range. An input range must |
125 | define the primitives `empty`, `popFront`, and `front`. The | |
b4c522fa IB |
126 | following code should compile for any input range. |
127 | ||
128 | ---- | |
129 | R r; // can define a range object | |
130 | if (r.empty) {} // can test for empty | |
131 | r.popFront(); // can invoke popFront() | |
132 | auto h = r.front; // can get the front of the range of non-void type | |
133 | ---- | |
134 | ||
135 | The following are rules of input ranges are assumed to hold true in all | |
136 | Phobos code. These rules are not checkable at compile-time, so not conforming | |
137 | to these rules when writing ranges or range based code will result in | |
138 | undefined behavior. | |
139 | ||
140 | $(UL | |
141 | $(LI `r.empty` returns `false` if and only if there is more data | |
142 | available in the range.) | |
143 | $(LI `r.empty` evaluated multiple times, without calling | |
144 | `r.popFront`, or otherwise mutating the range object or the | |
145 | underlying data, yields the same result for every evaluation.) | |
146 | $(LI `r.front` returns the current element in the range. | |
147 | It may return by value or by reference.) | |
148 | $(LI `r.front` can be legally evaluated if and only if evaluating | |
149 | `r.empty` has, or would have, equaled `false`.) | |
150 | $(LI `r.front` evaluated multiple times, without calling | |
151 | `r.popFront`, or otherwise mutating the range object or the | |
152 | underlying data, yields the same result for every evaluation.) | |
153 | $(LI `r.popFront` advances to the next element in the range.) | |
154 | $(LI `r.popFront` can be called if and only if evaluating `r.empty` | |
155 | has, or would have, equaled `false`.) | |
156 | ) | |
157 | ||
158 | Also, note that Phobos code assumes that the primitives `r.front` and | |
159 | `r.empty` are $(BIGOH 1) time complexity wise or "cheap" in terms of | |
160 | running time. $(BIGOH) statements in the documentation of range functions | |
161 | are made with this assumption. | |
162 | ||
5fee5ec3 IB |
163 | See_Also: |
164 | The header of $(MREF std,range) for tutorials on ranges. | |
165 | ||
b4c522fa IB |
166 | Params: |
167 | R = type to be tested | |
168 | ||
169 | Returns: | |
5fee5ec3 | 170 | `true` if R is an input range, `false` if not |
b4c522fa IB |
171 | */ |
172 | enum bool isInputRange(R) = | |
173 | is(typeof(R.init) == R) | |
174 | && is(ReturnType!((R r) => r.empty) == bool) | |
175 | && is(typeof((return ref R r) => r.front)) | |
176 | && !is(ReturnType!((R r) => r.front) == void) | |
177 | && is(typeof((R r) => r.popFront)); | |
178 | ||
179 | /// | |
180 | @safe unittest | |
181 | { | |
182 | struct A {} | |
183 | struct B | |
184 | { | |
185 | void popFront(); | |
186 | @property bool empty(); | |
187 | @property int front(); | |
188 | } | |
189 | static assert(!isInputRange!A); | |
190 | static assert( isInputRange!B); | |
191 | static assert( isInputRange!(int[])); | |
192 | static assert( isInputRange!(char[])); | |
193 | static assert(!isInputRange!(char[4])); | |
194 | static assert( isInputRange!(inout(int)[])); | |
195 | ||
196 | static struct NotDefaultConstructible | |
197 | { | |
198 | @disable this(); | |
199 | void popFront(); | |
200 | @property bool empty(); | |
201 | @property int front(); | |
202 | } | |
203 | static assert( isInputRange!NotDefaultConstructible); | |
204 | ||
205 | static struct NotDefaultConstructibleOrCopyable | |
206 | { | |
207 | @disable this(); | |
208 | @disable this(this); | |
209 | void popFront(); | |
210 | @property bool empty(); | |
211 | @property int front(); | |
212 | } | |
213 | static assert(isInputRange!NotDefaultConstructibleOrCopyable); | |
214 | ||
215 | static struct Frontless | |
216 | { | |
217 | void popFront(); | |
218 | @property bool empty(); | |
219 | } | |
220 | static assert(!isInputRange!Frontless); | |
221 | ||
222 | static struct VoidFront | |
223 | { | |
224 | void popFront(); | |
225 | @property bool empty(); | |
226 | void front(); | |
227 | } | |
228 | static assert(!isInputRange!VoidFront); | |
229 | } | |
230 | ||
231 | @safe unittest | |
232 | { | |
233 | import std.algorithm.comparison : equal; | |
234 | ||
235 | static struct R | |
236 | { | |
237 | static struct Front | |
238 | { | |
239 | R* impl; | |
240 | @property int value() { return impl._front; } | |
241 | alias value this; | |
242 | } | |
243 | ||
244 | int _front; | |
245 | ||
246 | @property bool empty() { return _front >= 3; } | |
247 | @property auto front() { return Front(&this); } | |
248 | void popFront() { _front++; } | |
249 | } | |
250 | R r; | |
251 | ||
252 | static assert(isInputRange!R); | |
253 | assert(r.equal([ 0, 1, 2 ])); | |
254 | } | |
255 | ||
256 | /+ | |
5fee5ec3 IB |
257 | puts the whole raw element `e` into `r`. doPut will not attempt to |
258 | iterate, slice or transcode `e` in any way shape or form. It will $(B only) | |
259 | call the correct primitive (`r.put(e)`, $(D r.front = e) or | |
260 | `r(e)` once. | |
b4c522fa | 261 | |
5fee5ec3 IB |
262 | This can be important when `e` needs to be placed in `r` unchanged. |
263 | Furthermore, it can be useful when working with `InputRange`s, as doPut | |
b4c522fa IB |
264 | guarantees that no more than a single element will be placed. |
265 | +/ | |
266 | private void doPut(R, E)(ref R r, auto ref E e) | |
267 | { | |
268 | static if (is(PointerTarget!R == struct)) | |
269 | enum usingPut = hasMember!(PointerTarget!R, "put"); | |
270 | else | |
271 | enum usingPut = hasMember!(R, "put"); | |
272 | ||
273 | static if (usingPut) | |
274 | { | |
275 | static assert(is(typeof(r.put(e))), | |
276 | "Cannot put a " ~ E.stringof ~ " into a " ~ R.stringof ~ "."); | |
277 | r.put(e); | |
278 | } | |
5fee5ec3 IB |
279 | else static if (isNarrowString!R && is(const(E) == const(typeof(r[0])))) |
280 | { | |
281 | // one character, we can put it | |
282 | r[0] = e; | |
283 | r = r[1 .. $]; | |
284 | } | |
285 | else static if (isNarrowString!R && isNarrowString!E && is(typeof(r[] = e))) | |
286 | { | |
287 | // slice assign. Note that this is a duplicate from put, but because | |
288 | // putChar uses doPut exclusively, we have to copy it here. | |
289 | immutable len = e.length; | |
290 | r[0 .. len] = e; | |
291 | r = r[len .. $]; | |
292 | } | |
b4c522fa IB |
293 | else static if (isInputRange!R) |
294 | { | |
295 | static assert(is(typeof(r.front = e)), | |
296 | "Cannot put a " ~ E.stringof ~ " into a " ~ R.stringof ~ "."); | |
297 | r.front = e; | |
298 | r.popFront(); | |
299 | } | |
300 | else static if (is(typeof(r(e)))) | |
301 | { | |
302 | r(e); | |
303 | } | |
304 | else | |
305 | { | |
306 | static assert(false, | |
307 | "Cannot put a " ~ E.stringof ~ " into a " ~ R.stringof ~ "."); | |
308 | } | |
309 | } | |
310 | ||
311 | @safe unittest | |
312 | { | |
313 | static assert(!isNativeOutputRange!(int, int)); | |
314 | static assert( isNativeOutputRange!(int[], int)); | |
315 | static assert(!isNativeOutputRange!(int[][], int)); | |
316 | ||
317 | static assert(!isNativeOutputRange!(int, int[])); | |
318 | static assert(!isNativeOutputRange!(int[], int[])); | |
319 | static assert( isNativeOutputRange!(int[][], int[])); | |
320 | ||
321 | static assert(!isNativeOutputRange!(int, int[][])); | |
322 | static assert(!isNativeOutputRange!(int[], int[][])); | |
323 | static assert(!isNativeOutputRange!(int[][], int[][])); | |
324 | ||
325 | static assert(!isNativeOutputRange!(int[4], int)); | |
326 | static assert( isNativeOutputRange!(int[4][], int)); //Scary! | |
327 | static assert( isNativeOutputRange!(int[4][], int[4])); | |
328 | ||
5fee5ec3 | 329 | static assert( isNativeOutputRange!( char[], char)); |
b4c522fa IB |
330 | static assert(!isNativeOutputRange!( char[], dchar)); |
331 | static assert( isNativeOutputRange!(dchar[], char)); | |
332 | static assert( isNativeOutputRange!(dchar[], dchar)); | |
333 | ||
334 | } | |
335 | ||
336 | /++ | |
5fee5ec3 | 337 | Outputs `e` to `r`. The exact effect is dependent upon the two |
b4c522fa IB |
338 | types. Several cases are accepted, as described below. The code snippets |
339 | are attempted in order, and the first to compile "wins" and gets | |
340 | evaluated. | |
341 | ||
5fee5ec3 IB |
342 | In this table "doPut" is a method that places `e` into `r`, using the |
343 | correct primitive: `r.put(e)` if `R` defines `put`, $(D r.front = e) | |
344 | if `r` is an input range (followed by `r.popFront()`), or `r(e)` | |
b4c522fa IB |
345 | otherwise. |
346 | ||
347 | $(BOOKTABLE , | |
348 | $(TR | |
349 | $(TH Code Snippet) | |
350 | $(TH Scenario) | |
351 | ) | |
352 | $(TR | |
5fee5ec3 IB |
353 | $(TD `r.doPut(e);`) |
354 | $(TD `R` specifically accepts an `E`.) | |
b4c522fa IB |
355 | ) |
356 | $(TR | |
357 | $(TD $(D r.doPut([ e ]);)) | |
5fee5ec3 | 358 | $(TD `R` specifically accepts an `E[]`.) |
b4c522fa IB |
359 | ) |
360 | $(TR | |
5fee5ec3 IB |
361 | $(TD `r.putChar(e);`) |
362 | $(TD `R` accepts some form of string or character. put will | |
363 | transcode the character `e` accordingly.) | |
b4c522fa IB |
364 | ) |
365 | $(TR | |
366 | $(TD $(D for (; !e.empty; e.popFront()) put(r, e.front);)) | |
5fee5ec3 | 367 | $(TD Copying range `E` into `R`.) |
b4c522fa IB |
368 | ) |
369 | ) | |
370 | ||
5fee5ec3 IB |
371 | Tip: `put` should $(I not) be used "UFCS-style", e.g. `r.put(e)`. |
372 | Doing this may call `R.put` directly, by-passing any transformation | |
373 | feature provided by `Range.put`. $(D put(r, e)) is prefered. | |
b4c522fa IB |
374 | +/ |
375 | void put(R, E)(ref R r, E e) | |
376 | { | |
377 | //First level: simply straight up put. | |
378 | static if (is(typeof(doPut(r, e)))) | |
379 | { | |
380 | doPut(r, e); | |
381 | } | |
382 | //Optional optimization block for straight up array to array copy. | |
5fee5ec3 IB |
383 | else static if (isDynamicArray!R && |
384 | !isAutodecodableString!R && | |
385 | isDynamicArray!E && | |
386 | is(typeof(r[] = e[]))) | |
b4c522fa IB |
387 | { |
388 | immutable len = e.length; | |
389 | r[0 .. len] = e[]; | |
390 | r = r[len .. $]; | |
391 | } | |
392 | //Accepts E[] ? | |
393 | else static if (is(typeof(doPut(r, [e]))) && !isDynamicArray!R) | |
394 | { | |
395 | if (__ctfe) | |
396 | { | |
397 | E[1] arr = [e]; | |
398 | doPut(r, arr[]); | |
399 | } | |
400 | else | |
401 | doPut(r, (ref e) @trusted { return (&e)[0 .. 1]; }(e)); | |
402 | } | |
403 | //special case for char to string. | |
404 | else static if (isSomeChar!E && is(typeof(putChar(r, e)))) | |
405 | { | |
406 | putChar(r, e); | |
407 | } | |
408 | //Extract each element from the range | |
409 | //We can use "put" here, so we can recursively test a RoR of E. | |
410 | else static if (isInputRange!E && is(typeof(put(r, e.front)))) | |
411 | { | |
412 | //Special optimization: If E is a narrow string, and r accepts characters no-wider than the string's | |
413 | //Then simply feed the characters 1 by 1. | |
5fee5ec3 | 414 | static if (isAutodecodableString!E && !isAggregateType!E && ( |
b4c522fa IB |
415 | (is(E : const char[]) && is(typeof(doPut(r, char.max))) && !is(typeof(doPut(r, dchar.max))) && |
416 | !is(typeof(doPut(r, wchar.max)))) || | |
417 | (is(E : const wchar[]) && is(typeof(doPut(r, wchar.max))) && !is(typeof(doPut(r, dchar.max)))) ) ) | |
418 | { | |
419 | foreach (c; e) | |
420 | doPut(r, c); | |
421 | } | |
422 | else | |
423 | { | |
424 | for (; !e.empty; e.popFront()) | |
425 | put(r, e.front); | |
426 | } | |
427 | } | |
428 | else | |
429 | { | |
430 | static assert(false, "Cannot put a " ~ E.stringof ~ " into a " ~ R.stringof ~ "."); | |
431 | } | |
432 | } | |
433 | ||
5fee5ec3 IB |
434 | /** |
435 | * When an output range's `put` method only accepts elements of type | |
436 | * `T`, use the global `put` to handle outputting a `T[]` to the range | |
437 | * or vice-versa. | |
438 | */ | |
439 | @safe pure unittest | |
440 | { | |
441 | import std.traits : isSomeChar; | |
442 | ||
443 | static struct A | |
444 | { | |
445 | string data; | |
446 | ||
447 | void put(C)(C c) if (isSomeChar!C) | |
448 | { | |
449 | data ~= c; | |
450 | } | |
451 | } | |
452 | static assert(isOutputRange!(A, char)); | |
453 | ||
454 | auto a = A(); | |
455 | put(a, "Hello"); | |
456 | assert(a.data == "Hello"); | |
457 | } | |
458 | ||
459 | /** | |
460 | * `put` treats dynamic arrays as array slices, and will call `popFront` | |
461 | * on the slice after an element has been copied. | |
462 | * | |
463 | * Be sure to save the position of the array before calling `put`. | |
464 | */ | |
465 | @safe pure nothrow unittest | |
466 | { | |
467 | int[] a = [1, 2, 3], b = [10, 20]; | |
468 | auto c = a; | |
469 | put(a, b); | |
470 | assert(c == [10, 20, 3]); | |
471 | // at this point, a was advanced twice, so it only contains | |
472 | // its last element while c represents the whole array | |
473 | assert(a == [3]); | |
474 | } | |
475 | ||
476 | /** | |
477 | * It's also possible to `put` any width strings or characters into narrow | |
478 | * strings -- put does the conversion for you. | |
479 | * | |
480 | * Note that putting the same width character as the target buffer type is | |
481 | * `nothrow`, but transcoding can throw a $(REF UTFException, std, utf). | |
482 | */ | |
483 | @safe pure unittest | |
484 | { | |
485 | // the elements must be mutable, so using string or const(char)[] | |
486 | // won't compile | |
487 | char[] s1 = new char[13]; | |
488 | auto r1 = s1; | |
489 | put(r1, "Hello, World!"w); | |
490 | assert(s1 == "Hello, World!"); | |
491 | } | |
492 | ||
493 | @safe pure nothrow unittest | |
494 | { | |
495 | // same thing, just using same character width. | |
496 | char[] s1 = new char[13]; | |
497 | auto r1 = s1; | |
498 | put(r1, "Hello, World!"); | |
499 | assert(s1 == "Hello, World!"); | |
500 | } | |
501 | ||
502 | ||
b4c522fa IB |
503 | @safe pure nothrow @nogc unittest |
504 | { | |
5fee5ec3 | 505 | static struct R() { void put(scope const(char)[]) {} } |
b4c522fa IB |
506 | R!() r; |
507 | put(r, 'a'); | |
508 | } | |
509 | ||
510 | //Helper function to handle chars as quickly and as elegantly as possible | |
511 | //Assumes r.put(e)/r(e) has already been tested | |
512 | private void putChar(R, E)(ref R r, E e) | |
513 | if (isSomeChar!E) | |
514 | { | |
5fee5ec3 | 515 | // https://issues.dlang.org/show_bug.cgi?id=9186: Can't use (E[]).init |
b4c522fa IB |
516 | ref const( char)[] cstringInit(); |
517 | ref const(wchar)[] wstringInit(); | |
518 | ref const(dchar)[] dstringInit(); | |
519 | ||
5fee5ec3 IB |
520 | enum csCond = is(typeof(doPut(r, cstringInit()))); |
521 | enum wsCond = is(typeof(doPut(r, wstringInit()))); | |
522 | enum dsCond = is(typeof(doPut(r, dstringInit()))); | |
b4c522fa IB |
523 | |
524 | //Use "max" to avoid static type demotion | |
525 | enum ccCond = is(typeof(doPut(r, char.max))); | |
526 | enum wcCond = is(typeof(doPut(r, wchar.max))); | |
527 | //enum dcCond = is(typeof(doPut(r, dchar.max))); | |
528 | ||
529 | //Fast transform a narrow char into a wider string | |
530 | static if ((wsCond && E.sizeof < wchar.sizeof) || (dsCond && E.sizeof < dchar.sizeof)) | |
531 | { | |
532 | enum w = wsCond && E.sizeof < wchar.sizeof; | |
533 | Select!(w, wchar, dchar) c = e; | |
534 | typeof(c)[1] arr = [c]; | |
535 | doPut(r, arr[]); | |
536 | } | |
537 | //Encode a wide char into a narrower string | |
538 | else static if (wsCond || csCond) | |
539 | { | |
540 | import std.utf : encode; | |
541 | /+static+/ Select!(wsCond, wchar[2], char[4]) buf; //static prevents purity. | |
542 | doPut(r, buf[0 .. encode(buf, e)]); | |
543 | } | |
544 | //Slowly encode a wide char into a series of narrower chars | |
545 | else static if (wcCond || ccCond) | |
546 | { | |
547 | import std.encoding : encode; | |
548 | alias C = Select!(wcCond, wchar, char); | |
549 | encode!(C, R)(e, r); | |
550 | } | |
551 | else | |
552 | { | |
553 | static assert(false, "Cannot put a " ~ E.stringof ~ " into a " ~ R.stringof ~ "."); | |
554 | } | |
555 | } | |
556 | ||
557 | pure @safe unittest | |
558 | { | |
559 | auto f = delegate (const(char)[]) {}; | |
560 | putChar(f, cast(dchar)'a'); | |
561 | } | |
562 | ||
563 | ||
564 | @safe pure unittest | |
565 | { | |
5fee5ec3 | 566 | static struct R() { void put(scope const(char)[]) {} } |
b4c522fa IB |
567 | R!() r; |
568 | putChar(r, 'a'); | |
569 | } | |
570 | ||
571 | @safe unittest | |
572 | { | |
573 | struct A {} | |
574 | static assert(!isInputRange!(A)); | |
575 | struct B | |
576 | { | |
577 | void put(int) {} | |
578 | } | |
579 | B b; | |
580 | put(b, 5); | |
581 | } | |
582 | ||
b4c522fa IB |
583 | @safe unittest |
584 | { | |
585 | int[] a = new int[10]; | |
586 | int b; | |
587 | static assert(isInputRange!(typeof(a))); | |
588 | put(a, b); | |
589 | } | |
590 | ||
591 | @safe unittest | |
592 | { | |
5fee5ec3 | 593 | void myprint(scope const(char)[] s) { } |
b4c522fa IB |
594 | auto r = &myprint; |
595 | put(r, 'a'); | |
596 | } | |
597 | ||
598 | @safe unittest | |
599 | { | |
600 | int[] a = new int[10]; | |
601 | static assert(!__traits(compiles, put(a, 1.0L))); | |
602 | put(a, 1); | |
603 | assert(a.length == 9); | |
604 | /* | |
605 | * a[0] = 65; // OK | |
606 | * a[0] = 'A'; // OK | |
607 | * a[0] = "ABC"[0]; // OK | |
608 | * put(a, "ABC"); // OK | |
609 | */ | |
610 | put(a, "ABC"); | |
611 | assert(a.length == 6); | |
612 | } | |
613 | ||
614 | @safe unittest | |
615 | { | |
616 | char[] a = new char[10]; | |
617 | static assert(!__traits(compiles, put(a, 1.0L))); | |
618 | static assert(!__traits(compiles, put(a, 1))); | |
5fee5ec3 IB |
619 | //char[] is now an output range for char, wchar, dchar, and ranges of such. |
620 | static assert(__traits(compiles, putChar(a, 'a'))); | |
621 | static assert(__traits(compiles, put(a, wchar('a')))); | |
622 | static assert(__traits(compiles, put(a, dchar('a')))); | |
623 | static assert(__traits(compiles, put(a, "ABC"))); | |
624 | static assert(__traits(compiles, put(a, "ABC"w))); | |
625 | static assert(__traits(compiles, put(a, "ABC"d))); | |
626 | } | |
627 | ||
628 | @safe unittest | |
629 | { | |
630 | // attempt putting into narrow strings by transcoding | |
631 | char[] a = new char[10]; | |
632 | auto b = a; | |
633 | put(a, "ABC"w); | |
634 | assert(b[0 .. 3] == "ABC"); | |
635 | assert(a.length == 7); | |
636 | ||
637 | a = b; // reset | |
638 | put(a, 'λ'); | |
639 | assert(b[0 .. 2] == "λ"); | |
640 | assert(a.length == 8); | |
641 | ||
642 | a = b; // reset | |
643 | put(a, "ABC"d); | |
644 | assert(b[0 .. 3] == "ABC"); | |
645 | assert(a.length == 7); | |
646 | ||
647 | a = b; // reset | |
648 | put(a, '𐐷'); | |
649 | assert(b[0 .. 4] == "𐐷"); | |
650 | assert(a.length == 6); | |
651 | ||
652 | wchar[] aw = new wchar[10]; | |
653 | auto bw = aw; | |
654 | put(aw, "ABC"); | |
655 | assert(bw[0 .. 3] == "ABC"w); | |
656 | assert(aw.length == 7); | |
657 | ||
658 | aw = bw; // reset | |
659 | put(aw, 'λ'); | |
660 | assert(bw[0 .. 1] == "λ"w); | |
661 | assert(aw.length == 9); | |
662 | ||
663 | aw = bw; // reset | |
664 | put(aw, "ABC"d); | |
665 | assert(bw[0 .. 3] == "ABC"w); | |
666 | assert(aw.length == 7); | |
667 | ||
668 | aw = bw; // reset | |
669 | put(aw, '𐐷'); | |
670 | assert(bw[0 .. 2] == "𐐷"w); | |
671 | assert(aw.length == 8); | |
672 | ||
673 | aw = bw; // reset | |
674 | put(aw, "𐐷"); // try transcoding from char[] | |
675 | assert(bw[0 .. 2] == "𐐷"w); | |
676 | assert(aw.length == 8); | |
b4c522fa IB |
677 | } |
678 | ||
679 | @safe unittest | |
680 | { | |
681 | int[][] a = new int[][10]; | |
682 | int[] b = new int[10]; | |
683 | int c; | |
684 | put(b, c); | |
685 | assert(b.length == 9); | |
686 | put(a, b); | |
687 | assert(a.length == 9); | |
688 | static assert(!__traits(compiles, put(a, c))); | |
689 | } | |
690 | ||
691 | @safe unittest | |
692 | { | |
693 | int[][] a = new int[][](3); | |
694 | int[] b = [1]; | |
695 | auto aa = a; | |
696 | put(aa, b); | |
697 | assert(aa == [[], []]); | |
698 | assert(a == [[1], [], []]); | |
699 | int[][3] c = [2]; | |
700 | aa = a; | |
701 | put(aa, c[]); | |
702 | assert(aa.empty); | |
703 | assert(a == [[2], [2], [2]]); | |
704 | } | |
705 | ||
706 | @safe unittest | |
707 | { | |
708 | // Test fix for bug 7476. | |
709 | struct LockingTextWriter | |
710 | { | |
711 | void put(dchar c){} | |
712 | } | |
713 | struct RetroResult | |
714 | { | |
715 | bool end = false; | |
716 | @property bool empty() const { return end; } | |
717 | @property dchar front(){ return 'a'; } | |
718 | void popFront(){ end = true; } | |
719 | } | |
720 | LockingTextWriter w; | |
5fee5ec3 IB |
721 | RetroResult re; |
722 | put(w, re); | |
b4c522fa IB |
723 | } |
724 | ||
725 | @system unittest | |
726 | { | |
727 | import std.conv : to; | |
728 | import std.meta : AliasSeq; | |
729 | import std.typecons : tuple; | |
730 | ||
731 | static struct PutC(C) | |
732 | { | |
733 | string result; | |
734 | void put(const(C) c) { result ~= to!string((&c)[0 .. 1]); } | |
735 | } | |
736 | static struct PutS(C) | |
737 | { | |
738 | string result; | |
739 | void put(const(C)[] s) { result ~= to!string(s); } | |
740 | } | |
741 | static struct PutSS(C) | |
742 | { | |
743 | string result; | |
744 | void put(const(C)[][] ss) | |
745 | { | |
746 | foreach (s; ss) | |
747 | result ~= to!string(s); | |
748 | } | |
749 | } | |
750 | ||
751 | PutS!char p; | |
752 | putChar(p, cast(dchar)'a'); | |
753 | ||
754 | //Source Char | |
5fee5ec3 IB |
755 | static foreach (SC; AliasSeq!(char, wchar, dchar)) |
756 | {{ | |
b4c522fa IB |
757 | SC ch = 'I'; |
758 | dchar dh = '♥'; | |
759 | immutable(SC)[] s = "日本語!"; | |
760 | immutable(SC)[][] ss = ["日本語", "が", "好き", "ですか", "?"]; | |
761 | ||
762 | //Target Char | |
5fee5ec3 | 763 | static foreach (TC; AliasSeq!(char, wchar, dchar)) |
b4c522fa IB |
764 | { |
765 | //Testing PutC and PutS | |
5fee5ec3 IB |
766 | static foreach (Type; AliasSeq!(PutC!TC, PutS!TC)) |
767 | {{ | |
b4c522fa IB |
768 | Type type; |
769 | auto sink = new Type(); | |
770 | ||
771 | //Testing put and sink | |
772 | foreach (value ; tuple(type, sink)) | |
773 | { | |
774 | put(value, ch); | |
775 | assert(value.result == "I"); | |
776 | put(value, dh); | |
777 | assert(value.result == "I♥"); | |
778 | put(value, s); | |
779 | assert(value.result == "I♥日本語!"); | |
780 | put(value, ss); | |
781 | assert(value.result == "I♥日本語!日本語が好きですか?"); | |
782 | } | |
5fee5ec3 | 783 | }} |
b4c522fa | 784 | } |
5fee5ec3 | 785 | }} |
b4c522fa IB |
786 | } |
787 | ||
788 | @safe unittest | |
789 | { | |
790 | static struct CharRange | |
791 | { | |
792 | char c; | |
793 | enum empty = false; | |
794 | void popFront(){} | |
795 | ref char front() return @property | |
796 | { | |
797 | return c; | |
798 | } | |
799 | } | |
800 | CharRange c; | |
801 | put(c, cast(dchar)'H'); | |
802 | put(c, "hello"d); | |
803 | } | |
804 | ||
5fee5ec3 | 805 | // https://issues.dlang.org/show_bug.cgi?id=9823 |
b4c522fa IB |
806 | @system unittest |
807 | { | |
b4c522fa IB |
808 | const(char)[] r; |
809 | void delegate(const(char)[]) dg = (s) { r = s; }; | |
810 | put(dg, ["ABC"]); | |
811 | assert(r == "ABC"); | |
812 | } | |
813 | ||
5fee5ec3 | 814 | // https://issues.dlang.org/show_bug.cgi?id=10571 |
b4c522fa IB |
815 | @safe unittest |
816 | { | |
5fee5ec3 | 817 | import std.format.write : formattedWrite; |
b4c522fa | 818 | string buf; |
5fee5ec3 | 819 | formattedWrite((scope const(char)[] s) { buf ~= s; }, "%s", "hello"); |
b4c522fa IB |
820 | assert(buf == "hello"); |
821 | } | |
822 | ||
823 | @safe unittest | |
824 | { | |
5fee5ec3 | 825 | import std.format.write : formattedWrite; |
b4c522fa IB |
826 | import std.meta : AliasSeq; |
827 | struct PutC(C) | |
828 | { | |
829 | void put(C){} | |
830 | } | |
831 | struct PutS(C) | |
832 | { | |
833 | void put(const(C)[]){} | |
834 | } | |
835 | struct CallC(C) | |
836 | { | |
837 | void opCall(C){} | |
838 | } | |
839 | struct CallS(C) | |
840 | { | |
841 | void opCall(const(C)[]){} | |
842 | } | |
843 | struct FrontC(C) | |
844 | { | |
845 | enum empty = false; | |
846 | auto front()@property{return C.init;} | |
847 | void front(C)@property{} | |
848 | void popFront(){} | |
849 | } | |
850 | struct FrontS(C) | |
851 | { | |
852 | enum empty = false; | |
853 | auto front()@property{return C[].init;} | |
854 | void front(const(C)[])@property{} | |
855 | void popFront(){} | |
856 | } | |
857 | void foo() | |
858 | { | |
5fee5ec3 IB |
859 | static foreach (C; AliasSeq!(char, wchar, dchar)) |
860 | {{ | |
b4c522fa IB |
861 | formattedWrite((C c){}, "", 1, 'a', cast(wchar)'a', cast(dchar)'a', "a"c, "a"w, "a"d); |
862 | formattedWrite((const(C)[]){}, "", 1, 'a', cast(wchar)'a', cast(dchar)'a', "a"c, "a"w, "a"d); | |
863 | formattedWrite(PutC!C(), "", 1, 'a', cast(wchar)'a', cast(dchar)'a', "a"c, "a"w, "a"d); | |
864 | formattedWrite(PutS!C(), "", 1, 'a', cast(wchar)'a', cast(dchar)'a', "a"c, "a"w, "a"d); | |
865 | CallC!C callC; | |
866 | CallS!C callS; | |
867 | formattedWrite(callC, "", 1, 'a', cast(wchar)'a', cast(dchar)'a', "a"c, "a"w, "a"d); | |
868 | formattedWrite(callS, "", 1, 'a', cast(wchar)'a', cast(dchar)'a', "a"c, "a"w, "a"d); | |
869 | formattedWrite(FrontC!C(), "", 1, 'a', cast(wchar)'a', cast(dchar)'a', "a"c, "a"w, "a"d); | |
870 | formattedWrite(FrontS!C(), "", 1, 'a', cast(wchar)'a', cast(dchar)'a', "a"c, "a"w, "a"d); | |
5fee5ec3 | 871 | }} |
b4c522fa IB |
872 | formattedWrite((dchar[]).init, "", 1, 'a', cast(wchar)'a', cast(dchar)'a', "a"c, "a"w, "a"d); |
873 | } | |
874 | } | |
875 | ||
876 | /+ | |
5fee5ec3 IB |
877 | Returns `true` if `R` is a native output range for elements of type |
878 | `E`. An output range is defined functionally as a range that | |
b4c522fa | 879 | supports the operation $(D doPut(r, e)) as defined above. if $(D doPut(r, e)) |
5fee5ec3 | 880 | is valid, then `put(r,e)` will have the same behavior. |
b4c522fa | 881 | |
5fee5ec3 | 882 | The two guarantees isNativeOutputRange gives over the larger `isOutputRange` |
b4c522fa | 883 | are: |
5fee5ec3 IB |
884 | 1: `e` is $(B exactly) what will be placed (not `[e]`, for example). |
885 | 2: if `E` is a non $(empty) `InputRange`, then placing `e` is | |
b4c522fa IB |
886 | guaranteed to not overflow the range. |
887 | +/ | |
888 | package(std) enum bool isNativeOutputRange(R, E) = | |
889 | is(typeof(doPut(lvalueOf!R, lvalueOf!E))); | |
890 | ||
891 | @safe unittest | |
892 | { | |
893 | int[] r = new int[](4); | |
894 | static assert(isInputRange!(int[])); | |
895 | static assert( isNativeOutputRange!(int[], int)); | |
896 | static assert(!isNativeOutputRange!(int[], int[])); | |
897 | static assert( isOutputRange!(int[], int[])); | |
898 | ||
899 | if (!r.empty) | |
900 | put(r, 1); //guaranteed to succeed | |
901 | if (!r.empty) | |
902 | put(r, [1, 2]); //May actually error out. | |
903 | } | |
904 | ||
905 | /++ | |
5fee5ec3 IB |
906 | Returns `true` if `R` is an output range for elements of type |
907 | `E`. An output range is defined functionally as a range that | |
b4c522fa | 908 | supports the operation $(D put(r, e)) as defined above. |
5fee5ec3 IB |
909 | |
910 | See_Also: | |
911 | The header of $(MREF std,range) for tutorials on ranges. | |
b4c522fa IB |
912 | +/ |
913 | enum bool isOutputRange(R, E) = | |
914 | is(typeof(put(lvalueOf!R, lvalueOf!E))); | |
915 | ||
916 | /// | |
917 | @safe unittest | |
918 | { | |
5fee5ec3 | 919 | void myprint(scope const(char)[] s) { } |
b4c522fa IB |
920 | static assert(isOutputRange!(typeof(&myprint), char)); |
921 | ||
5fee5ec3 | 922 | static assert( isOutputRange!(char[], char)); |
b4c522fa IB |
923 | static assert( isOutputRange!(dchar[], wchar)); |
924 | static assert( isOutputRange!(dchar[], dchar)); | |
925 | } | |
926 | ||
927 | @safe unittest | |
928 | { | |
929 | import std.array; | |
930 | import std.stdio : writeln; | |
931 | ||
932 | auto app = appender!string(); | |
933 | string s; | |
934 | static assert( isOutputRange!(Appender!string, string)); | |
935 | static assert( isOutputRange!(Appender!string*, string)); | |
936 | static assert(!isOutputRange!(Appender!string, int)); | |
5fee5ec3 | 937 | static assert( isOutputRange!(wchar[], wchar)); |
b4c522fa IB |
938 | static assert( isOutputRange!(dchar[], char)); |
939 | static assert( isOutputRange!(dchar[], string)); | |
940 | static assert( isOutputRange!(dchar[], wstring)); | |
941 | static assert( isOutputRange!(dchar[], dstring)); | |
942 | ||
943 | static assert(!isOutputRange!(const(int)[], int)); | |
944 | static assert(!isOutputRange!(inout(int)[], int)); | |
945 | } | |
946 | ||
947 | ||
948 | /** | |
5fee5ec3 IB |
949 | Returns `true` if `R` is a forward range. A forward range is an |
950 | input range `r` that can save "checkpoints" by saving `r.save` | |
951 | to another value of type `R`. Notable examples of input ranges that | |
b4c522fa IB |
952 | are $(I not) forward ranges are file/socket ranges; copying such a |
953 | range will not save the position in the stream, and they most likely | |
954 | reuse an internal buffer as the entire stream does not sit in | |
955 | memory. Subsequently, advancing either the original or the copy will | |
956 | advance the stream, so the copies are not independent. | |
957 | ||
958 | The following code should compile for any forward range. | |
959 | ||
960 | ---- | |
961 | static assert(isInputRange!R); | |
962 | R r1; | |
963 | auto s1 = r1.save; | |
964 | static assert(is(typeof(s1) == R)); | |
965 | ---- | |
966 | ||
5fee5ec3 IB |
967 | Saving a range is not duplicating it; in the example above, `r1` |
968 | and `r2` still refer to the same underlying data. They just | |
b4c522fa IB |
969 | navigate that data independently. |
970 | ||
971 | The semantics of a forward range (not checkable during compilation) | |
972 | are the same as for an input range, with the additional requirement | |
973 | that backtracking must be possible by saving a copy of the range | |
5fee5ec3 IB |
974 | object with `save` and using it later. |
975 | ||
976 | `save` behaves in many ways like a copy constructor, and its | |
977 | implementation typically is done using copy construction. | |
978 | ||
979 | The existence of a copy constructor, however, does not imply | |
980 | the range is a forward range. For example, a range that reads | |
981 | from a TTY consumes its input and cannot save its place and | |
982 | read it again, and so cannot be a forward range and cannot | |
983 | have a `save` function. | |
984 | ||
985 | ||
986 | See_Also: | |
987 | The header of $(MREF std,range) for tutorials on ranges. | |
b4c522fa IB |
988 | */ |
989 | enum bool isForwardRange(R) = isInputRange!R | |
990 | && is(ReturnType!((R r) => r.save) == R); | |
991 | ||
992 | /// | |
993 | @safe unittest | |
994 | { | |
995 | static assert(!isForwardRange!(int)); | |
996 | static assert( isForwardRange!(int[])); | |
997 | static assert( isForwardRange!(inout(int)[])); | |
998 | } | |
999 | ||
1000 | @safe unittest | |
1001 | { | |
1002 | // BUG 14544 | |
1003 | struct R14544 | |
1004 | { | |
1005 | int front() { return 0;} | |
1006 | void popFront() {} | |
1007 | bool empty() { return false; } | |
1008 | R14544 save() {return this;} | |
1009 | } | |
1010 | ||
1011 | static assert( isForwardRange!R14544 ); | |
1012 | } | |
1013 | ||
1014 | /** | |
5fee5ec3 IB |
1015 | Returns `true` if `R` is a bidirectional range. A bidirectional |
1016 | range is a forward range that also offers the primitives `back` and | |
1017 | `popBack`. The following code should compile for any bidirectional | |
b4c522fa IB |
1018 | range. |
1019 | ||
1020 | The semantics of a bidirectional range (not checkable during | |
5fee5ec3 IB |
1021 | compilation) are assumed to be the following (`r` is an object of |
1022 | type `R`): | |
1023 | ||
1024 | $(UL $(LI `r.back` returns (possibly a reference to) the last | |
1025 | element in the range. Calling `r.back` is allowed only if calling | |
1026 | `r.empty` has, or would have, returned `false`.)) | |
b4c522fa | 1027 | |
5fee5ec3 IB |
1028 | See_Also: |
1029 | The header of $(MREF std,range) for tutorials on ranges. | |
b4c522fa IB |
1030 | */ |
1031 | enum bool isBidirectionalRange(R) = isForwardRange!R | |
1032 | && is(typeof((R r) => r.popBack)) | |
1033 | && is(ReturnType!((R r) => r.back) == ElementType!R); | |
1034 | ||
1035 | /// | |
1036 | @safe unittest | |
1037 | { | |
1038 | alias R = int[]; | |
1039 | R r = [0,1]; | |
1040 | static assert(isForwardRange!R); // is forward range | |
1041 | r.popBack(); // can invoke popBack | |
1042 | auto t = r.back; // can get the back of the range | |
1043 | auto w = r.front; | |
1044 | static assert(is(typeof(t) == typeof(w))); // same type for front and back | |
1045 | } | |
1046 | ||
1047 | @safe unittest | |
1048 | { | |
1049 | struct A {} | |
1050 | struct B | |
1051 | { | |
1052 | void popFront(); | |
1053 | @property bool empty(); | |
1054 | @property int front(); | |
1055 | } | |
1056 | struct C | |
1057 | { | |
1058 | @property bool empty(); | |
1059 | @property C save(); | |
1060 | void popFront(); | |
1061 | @property int front(); | |
1062 | void popBack(); | |
1063 | @property int back(); | |
1064 | } | |
1065 | static assert(!isBidirectionalRange!(A)); | |
1066 | static assert(!isBidirectionalRange!(B)); | |
1067 | static assert( isBidirectionalRange!(C)); | |
1068 | static assert( isBidirectionalRange!(int[])); | |
1069 | static assert( isBidirectionalRange!(char[])); | |
1070 | static assert( isBidirectionalRange!(inout(int)[])); | |
1071 | } | |
1072 | ||
1073 | /** | |
5fee5ec3 | 1074 | Returns `true` if `R` is a random-access range. A random-access |
b4c522fa | 1075 | range is a bidirectional range that also offers the primitive $(D |
5fee5ec3 IB |
1076 | opIndex), OR an infinite forward range that offers `opIndex`. In |
1077 | either case, the range must either offer `length` or be | |
b4c522fa IB |
1078 | infinite. The following code should compile for any random-access |
1079 | range. | |
1080 | ||
1081 | The semantics of a random-access range (not checkable during | |
5fee5ec3 IB |
1082 | compilation) are assumed to be the following (`r` is an object of |
1083 | type `R`): $(UL $(LI `r.opIndex(n)` returns a reference to the | |
1084 | `n`th element in the range.)) | |
b4c522fa | 1085 | |
5fee5ec3 IB |
1086 | Although `char[]` and `wchar[]` (as well as their qualified |
1087 | versions including `string` and `wstring`) are arrays, $(D | |
1088 | isRandomAccessRange) yields `false` for them because they use | |
b4c522fa IB |
1089 | variable-length encodings (UTF-8 and UTF-16 respectively). These types |
1090 | are bidirectional ranges only. | |
5fee5ec3 IB |
1091 | |
1092 | See_Also: | |
1093 | The header of $(MREF std,range) for tutorials on ranges. | |
b4c522fa IB |
1094 | */ |
1095 | enum bool isRandomAccessRange(R) = | |
1096 | is(typeof(lvalueOf!R[1]) == ElementType!R) | |
5fee5ec3 | 1097 | && !(isAutodecodableString!R && !isAggregateType!R) |
b4c522fa IB |
1098 | && isForwardRange!R |
1099 | && (isBidirectionalRange!R || isInfinite!R) | |
1100 | && (hasLength!R || isInfinite!R) | |
1101 | && (isInfinite!R || !is(typeof(lvalueOf!R[$ - 1])) | |
1102 | || is(typeof(lvalueOf!R[$ - 1]) == ElementType!R)); | |
1103 | ||
1104 | /// | |
1105 | @safe unittest | |
1106 | { | |
5fee5ec3 | 1107 | import std.traits : isAggregateType, isAutodecodableString; |
b4c522fa IB |
1108 | |
1109 | alias R = int[]; | |
1110 | ||
1111 | // range is finite and bidirectional or infinite and forward. | |
1112 | static assert(isBidirectionalRange!R || | |
1113 | isForwardRange!R && isInfinite!R); | |
1114 | ||
1115 | R r = [0,1]; | |
1116 | auto e = r[1]; // can index | |
1117 | auto f = r.front; | |
1118 | static assert(is(typeof(e) == typeof(f))); // same type for indexed and front | |
5fee5ec3 | 1119 | static assert(!(isAutodecodableString!R && !isAggregateType!R)); // narrow strings cannot be indexed as ranges |
b4c522fa IB |
1120 | static assert(hasLength!R || isInfinite!R); // must have length or be infinite |
1121 | ||
1122 | // $ must work as it does with arrays if opIndex works with $ | |
1123 | static if (is(typeof(r[$]))) | |
1124 | { | |
1125 | static assert(is(typeof(f) == typeof(r[$]))); | |
1126 | ||
1127 | // $ - 1 doesn't make sense with infinite ranges but needs to work | |
1128 | // with finite ones. | |
1129 | static if (!isInfinite!R) | |
1130 | static assert(is(typeof(f) == typeof(r[$ - 1]))); | |
1131 | } | |
1132 | } | |
1133 | ||
1134 | @safe unittest | |
1135 | { | |
1136 | struct A {} | |
1137 | struct B | |
1138 | { | |
1139 | void popFront(); | |
1140 | @property bool empty(); | |
1141 | @property int front(); | |
1142 | } | |
1143 | struct C | |
1144 | { | |
1145 | void popFront(); | |
1146 | @property bool empty(); | |
1147 | @property int front(); | |
1148 | void popBack(); | |
1149 | @property int back(); | |
1150 | } | |
1151 | struct D | |
1152 | { | |
1153 | @property bool empty(); | |
1154 | @property D save(); | |
1155 | @property int front(); | |
1156 | void popFront(); | |
1157 | @property int back(); | |
1158 | void popBack(); | |
1159 | ref int opIndex(uint); | |
1160 | @property size_t length(); | |
1161 | alias opDollar = length; | |
1162 | //int opSlice(uint, uint); | |
1163 | } | |
1164 | struct E | |
1165 | { | |
1166 | bool empty(); | |
1167 | E save(); | |
1168 | int front(); | |
1169 | void popFront(); | |
1170 | int back(); | |
1171 | void popBack(); | |
1172 | ref int opIndex(uint); | |
1173 | size_t length(); | |
1174 | alias opDollar = length; | |
1175 | //int opSlice(uint, uint); | |
1176 | } | |
1177 | static assert(!isRandomAccessRange!(A)); | |
1178 | static assert(!isRandomAccessRange!(B)); | |
1179 | static assert(!isRandomAccessRange!(C)); | |
1180 | static assert( isRandomAccessRange!(D)); | |
1181 | static assert( isRandomAccessRange!(E)); | |
1182 | static assert( isRandomAccessRange!(int[])); | |
1183 | static assert( isRandomAccessRange!(inout(int)[])); | |
1184 | } | |
1185 | ||
1186 | @safe unittest | |
1187 | { | |
1188 | // Test fix for bug 6935. | |
1189 | struct R | |
1190 | { | |
1191 | @disable this(); | |
1192 | ||
1193 | @property bool empty() const { return false; } | |
1194 | @property int front() const { return 0; } | |
1195 | void popFront() {} | |
1196 | ||
1197 | @property R save() { return this; } | |
1198 | ||
1199 | @property int back() const { return 0; } | |
1200 | void popBack(){} | |
1201 | ||
1202 | int opIndex(size_t n) const { return 0; } | |
1203 | @property size_t length() const { return 0; } | |
1204 | alias opDollar = length; | |
1205 | ||
1206 | void put(int e){ } | |
1207 | } | |
1208 | static assert(isInputRange!R); | |
1209 | static assert(isForwardRange!R); | |
1210 | static assert(isBidirectionalRange!R); | |
1211 | static assert(isRandomAccessRange!R); | |
1212 | static assert(isOutputRange!(R, int)); | |
1213 | } | |
1214 | ||
1215 | /** | |
5fee5ec3 IB |
1216 | Returns `true` iff `R` is an input range that supports the |
1217 | `moveFront` primitive, as well as `moveBack` and `moveAt` if it's a | |
b4c522fa | 1218 | bidirectional or random access range. These may be explicitly implemented, or |
5fee5ec3 | 1219 | may work via the default behavior of the module level functions `moveFront` |
b4c522fa IB |
1220 | and friends. The following code should compile for any range |
1221 | with mobile elements. | |
1222 | ||
1223 | ---- | |
1224 | alias E = ElementType!R; | |
1225 | R r; | |
1226 | static assert(isInputRange!R); | |
1227 | static assert(is(typeof(moveFront(r)) == E)); | |
1228 | static if (isBidirectionalRange!R) | |
1229 | static assert(is(typeof(moveBack(r)) == E)); | |
1230 | static if (isRandomAccessRange!R) | |
1231 | static assert(is(typeof(moveAt(r, 0)) == E)); | |
1232 | ---- | |
1233 | */ | |
1234 | enum bool hasMobileElements(R) = | |
1235 | isInputRange!R | |
1236 | && is(typeof(moveFront(lvalueOf!R)) == ElementType!R) | |
1237 | && (!isBidirectionalRange!R | |
1238 | || is(typeof(moveBack(lvalueOf!R)) == ElementType!R)) | |
1239 | && (!isRandomAccessRange!R | |
1240 | || is(typeof(moveAt(lvalueOf!R, 0)) == ElementType!R)); | |
1241 | ||
1242 | /// | |
1243 | @safe unittest | |
1244 | { | |
1245 | import std.algorithm.iteration : map; | |
1246 | import std.range : iota, repeat; | |
1247 | ||
1248 | static struct HasPostblit | |
1249 | { | |
1250 | this(this) {} | |
1251 | } | |
1252 | ||
1253 | auto nonMobile = map!"a"(repeat(HasPostblit.init)); | |
1254 | static assert(!hasMobileElements!(typeof(nonMobile))); | |
1255 | static assert( hasMobileElements!(int[])); | |
1256 | static assert( hasMobileElements!(inout(int)[])); | |
1257 | static assert( hasMobileElements!(typeof(iota(1000)))); | |
1258 | ||
1259 | static assert( hasMobileElements!( string)); | |
1260 | static assert( hasMobileElements!(dstring)); | |
1261 | static assert( hasMobileElements!( char[])); | |
1262 | static assert( hasMobileElements!(dchar[])); | |
1263 | } | |
1264 | ||
1265 | /** | |
5fee5ec3 IB |
1266 | The element type of `R`. `R` does not have to be a range. The |
1267 | element type is determined as the type yielded by `r.front` for an | |
1268 | object `r` of type `R`. For example, `ElementType!(T[])` is | |
1269 | `T` if `T[]` isn't a narrow string; if it is, the element type is | |
1270 | `dchar`. If `R` doesn't have `front`, `ElementType!R` is | |
1271 | `void`. | |
b4c522fa IB |
1272 | */ |
1273 | template ElementType(R) | |
1274 | { | |
1275 | static if (is(typeof(R.init.front.init) T)) | |
1276 | alias ElementType = T; | |
1277 | else | |
1278 | alias ElementType = void; | |
1279 | } | |
1280 | ||
1281 | /// | |
1282 | @safe unittest | |
1283 | { | |
1284 | import std.range : iota; | |
1285 | ||
1286 | // Standard arrays: returns the type of the elements of the array | |
1287 | static assert(is(ElementType!(int[]) == int)); | |
1288 | ||
1289 | // Accessing .front retrieves the decoded dchar | |
1290 | static assert(is(ElementType!(char[]) == dchar)); // rvalue | |
1291 | static assert(is(ElementType!(dchar[]) == dchar)); // lvalue | |
1292 | ||
1293 | // Ditto | |
1294 | static assert(is(ElementType!(string) == dchar)); | |
1295 | static assert(is(ElementType!(dstring) == immutable(dchar))); | |
1296 | ||
1297 | // For ranges it gets the type of .front. | |
1298 | auto range = iota(0, 10); | |
1299 | static assert(is(ElementType!(typeof(range)) == int)); | |
1300 | } | |
1301 | ||
1302 | @safe unittest | |
1303 | { | |
1304 | static assert(is(ElementType!(byte[]) == byte)); | |
1305 | static assert(is(ElementType!(wchar[]) == dchar)); // rvalue | |
1306 | static assert(is(ElementType!(wstring) == dchar)); | |
1307 | } | |
1308 | ||
1309 | @safe unittest | |
1310 | { | |
1311 | enum XYZ : string { a = "foo" } | |
1312 | auto x = XYZ.a.front; | |
1313 | immutable char[3] a = "abc"; | |
1314 | int[] i; | |
1315 | void[] buf; | |
1316 | static assert(is(ElementType!(XYZ) == dchar)); | |
1317 | static assert(is(ElementType!(typeof(a)) == dchar)); | |
1318 | static assert(is(ElementType!(typeof(i)) == int)); | |
1319 | static assert(is(ElementType!(typeof(buf)) == void)); | |
1320 | static assert(is(ElementType!(inout(int)[]) == inout(int))); | |
1321 | static assert(is(ElementType!(inout(int[])) == inout(int))); | |
1322 | } | |
1323 | ||
1324 | @safe unittest | |
1325 | { | |
1326 | static assert(is(ElementType!(int[5]) == int)); | |
1327 | static assert(is(ElementType!(int[0]) == int)); | |
1328 | static assert(is(ElementType!(char[5]) == dchar)); | |
1329 | static assert(is(ElementType!(char[0]) == dchar)); | |
1330 | } | |
1331 | ||
5fee5ec3 IB |
1332 | // https://issues.dlang.org/show_bug.cgi?id=11336 |
1333 | @safe unittest | |
b4c522fa IB |
1334 | { |
1335 | static struct S | |
1336 | { | |
1337 | this(this) @disable; | |
1338 | } | |
1339 | static assert(is(ElementType!(S[]) == S)); | |
1340 | } | |
1341 | ||
5fee5ec3 IB |
1342 | // https://issues.dlang.org/show_bug.cgi?id=11401 |
1343 | @safe unittest | |
b4c522fa IB |
1344 | { |
1345 | // ElementType should also work for non-@propety 'front' | |
1346 | struct E { ushort id; } | |
1347 | struct R | |
1348 | { | |
1349 | E front() { return E.init; } | |
1350 | } | |
1351 | static assert(is(ElementType!R == E)); | |
1352 | } | |
1353 | ||
1354 | /** | |
5fee5ec3 IB |
1355 | The encoding element type of `R`. For narrow strings (`char[]`, |
1356 | `wchar[]` and their qualified variants including `string` and | |
1357 | `wstring`), `ElementEncodingType` is the character type of the | |
1358 | string. For all other types, `ElementEncodingType` is the same as | |
1359 | `ElementType`. | |
b4c522fa IB |
1360 | */ |
1361 | template ElementEncodingType(R) | |
1362 | { | |
1363 | static if (is(StringTypeOf!R) && is(R : E[], E)) | |
1364 | alias ElementEncodingType = E; | |
1365 | else | |
1366 | alias ElementEncodingType = ElementType!R; | |
1367 | } | |
1368 | ||
1369 | /// | |
1370 | @safe unittest | |
1371 | { | |
1372 | import std.range : iota; | |
1373 | // internally the range stores the encoded type | |
1374 | static assert(is(ElementEncodingType!(char[]) == char)); | |
1375 | ||
1376 | static assert(is(ElementEncodingType!(wstring) == immutable(wchar))); | |
1377 | ||
1378 | static assert(is(ElementEncodingType!(byte[]) == byte)); | |
1379 | ||
1380 | auto range = iota(0, 10); | |
1381 | static assert(is(ElementEncodingType!(typeof(range)) == int)); | |
1382 | } | |
1383 | ||
1384 | @safe unittest | |
1385 | { | |
1386 | static assert(is(ElementEncodingType!(wchar[]) == wchar)); | |
1387 | static assert(is(ElementEncodingType!(dchar[]) == dchar)); | |
1388 | static assert(is(ElementEncodingType!(string) == immutable(char))); | |
1389 | static assert(is(ElementEncodingType!(dstring) == immutable(dchar))); | |
1390 | static assert(is(ElementEncodingType!(int[]) == int)); | |
1391 | } | |
1392 | ||
1393 | @safe unittest | |
1394 | { | |
1395 | enum XYZ : string { a = "foo" } | |
1396 | auto x = XYZ.a.front; | |
1397 | immutable char[3] a = "abc"; | |
1398 | int[] i; | |
1399 | void[] buf; | |
1400 | static assert(is(ElementType!(XYZ) : dchar)); | |
1401 | static assert(is(ElementEncodingType!(char[]) == char)); | |
1402 | static assert(is(ElementEncodingType!(string) == immutable char)); | |
1403 | static assert(is(ElementType!(typeof(a)) : dchar)); | |
1404 | static assert(is(ElementType!(typeof(i)) == int)); | |
1405 | static assert(is(ElementEncodingType!(typeof(i)) == int)); | |
1406 | static assert(is(ElementType!(typeof(buf)) : void)); | |
1407 | ||
1408 | static assert(is(ElementEncodingType!(inout char[]) : inout(char))); | |
1409 | } | |
1410 | ||
1411 | @safe unittest | |
1412 | { | |
1413 | static assert(is(ElementEncodingType!(int[5]) == int)); | |
1414 | static assert(is(ElementEncodingType!(int[0]) == int)); | |
1415 | static assert(is(ElementEncodingType!(char[5]) == char)); | |
1416 | static assert(is(ElementEncodingType!(char[0]) == char)); | |
1417 | } | |
1418 | ||
1419 | /** | |
5fee5ec3 | 1420 | Returns `true` if `R` is an input range and has swappable |
b4c522fa IB |
1421 | elements. The following code should compile for any range |
1422 | with swappable elements. | |
1423 | ||
1424 | ---- | |
1425 | R r; | |
1426 | static assert(isInputRange!R); | |
1427 | swap(r.front, r.front); | |
1428 | static if (isBidirectionalRange!R) swap(r.back, r.front); | |
1429 | static if (isRandomAccessRange!R) swap(r[0], r.front); | |
1430 | ---- | |
1431 | */ | |
1432 | template hasSwappableElements(R) | |
1433 | { | |
1434 | import std.algorithm.mutation : swap; | |
1435 | enum bool hasSwappableElements = isInputRange!R | |
1436 | && is(typeof((ref R r) => swap(r.front, r.front))) | |
1437 | && (!isBidirectionalRange!R | |
1438 | || is(typeof((ref R r) => swap(r.back, r.front)))) | |
1439 | && (!isRandomAccessRange!R | |
1440 | || is(typeof((ref R r) => swap(r[0], r.front)))); | |
1441 | } | |
1442 | ||
1443 | /// | |
1444 | @safe unittest | |
1445 | { | |
1446 | static assert(!hasSwappableElements!(const int[])); | |
1447 | static assert(!hasSwappableElements!(const(int)[])); | |
1448 | static assert(!hasSwappableElements!(inout(int)[])); | |
1449 | static assert( hasSwappableElements!(int[])); | |
1450 | ||
1451 | static assert(!hasSwappableElements!( string)); | |
1452 | static assert(!hasSwappableElements!(dstring)); | |
1453 | static assert(!hasSwappableElements!( char[])); | |
1454 | static assert( hasSwappableElements!(dchar[])); | |
1455 | } | |
1456 | ||
1457 | /** | |
5fee5ec3 | 1458 | Returns `true` if `R` is an input range and has mutable |
b4c522fa IB |
1459 | elements. The following code should compile for any range |
1460 | with assignable elements. | |
1461 | ||
1462 | ---- | |
1463 | R r; | |
1464 | static assert(isInputRange!R); | |
1465 | r.front = r.front; | |
1466 | static if (isBidirectionalRange!R) r.back = r.front; | |
1467 | static if (isRandomAccessRange!R) r[0] = r.front; | |
1468 | ---- | |
1469 | */ | |
1470 | enum bool hasAssignableElements(R) = isInputRange!R | |
1471 | && is(typeof(lvalueOf!R.front = lvalueOf!R.front)) | |
1472 | && (!isBidirectionalRange!R | |
1473 | || is(typeof(lvalueOf!R.back = lvalueOf!R.back))) | |
1474 | && (!isRandomAccessRange!R | |
1475 | || is(typeof(lvalueOf!R[0] = lvalueOf!R.front))); | |
1476 | ||
1477 | /// | |
1478 | @safe unittest | |
1479 | { | |
1480 | static assert(!hasAssignableElements!(const int[])); | |
1481 | static assert(!hasAssignableElements!(const(int)[])); | |
1482 | static assert( hasAssignableElements!(int[])); | |
1483 | static assert(!hasAssignableElements!(inout(int)[])); | |
1484 | ||
1485 | static assert(!hasAssignableElements!( string)); | |
1486 | static assert(!hasAssignableElements!(dstring)); | |
1487 | static assert(!hasAssignableElements!( char[])); | |
1488 | static assert( hasAssignableElements!(dchar[])); | |
1489 | } | |
1490 | ||
1491 | /** | |
5fee5ec3 | 1492 | Tests whether the range `R` has lvalue elements. These are defined as |
b4c522fa IB |
1493 | elements that can be passed by reference and have their address taken. |
1494 | The following code should compile for any range with lvalue elements. | |
1495 | ---- | |
1496 | void passByRef(ref ElementType!R stuff); | |
1497 | ... | |
1498 | static assert(isInputRange!R); | |
1499 | passByRef(r.front); | |
1500 | static if (isBidirectionalRange!R) passByRef(r.back); | |
1501 | static if (isRandomAccessRange!R) passByRef(r[0]); | |
1502 | ---- | |
1503 | */ | |
1504 | enum bool hasLvalueElements(R) = isInputRange!R | |
5fee5ec3 | 1505 | && is(typeof(isLvalue(lvalueOf!R.front))) |
b4c522fa | 1506 | && (!isBidirectionalRange!R |
5fee5ec3 | 1507 | || is(typeof(isLvalue(lvalueOf!R.back)))) |
b4c522fa | 1508 | && (!isRandomAccessRange!R |
5fee5ec3 IB |
1509 | || is(typeof(isLvalue(lvalueOf!R[0])))); |
1510 | ||
1511 | /* Compile successfully if argument of type T is an lvalue | |
1512 | */ | |
1513 | private void isLvalue(T)(T) | |
1514 | if (0); | |
1515 | ||
1516 | private void isLvalue(T)(ref T) | |
1517 | if (1); | |
b4c522fa IB |
1518 | |
1519 | /// | |
1520 | @safe unittest | |
1521 | { | |
1522 | import std.range : iota, chain; | |
1523 | ||
1524 | static assert( hasLvalueElements!(int[])); | |
1525 | static assert( hasLvalueElements!(const(int)[])); | |
1526 | static assert( hasLvalueElements!(inout(int)[])); | |
1527 | static assert( hasLvalueElements!(immutable(int)[])); | |
1528 | static assert(!hasLvalueElements!(typeof(iota(3)))); | |
1529 | ||
1530 | static assert(!hasLvalueElements!( string)); | |
1531 | static assert( hasLvalueElements!(dstring)); | |
1532 | static assert(!hasLvalueElements!( char[])); | |
1533 | static assert( hasLvalueElements!(dchar[])); | |
1534 | ||
1535 | auto c = chain([1, 2, 3], [4, 5, 6]); | |
1536 | static assert( hasLvalueElements!(typeof(c))); | |
1537 | } | |
1538 | ||
1539 | @safe unittest | |
1540 | { | |
1541 | // bugfix 6336 | |
1542 | struct S { immutable int value; } | |
1543 | static assert( isInputRange!(S[])); | |
1544 | static assert( hasLvalueElements!(S[])); | |
1545 | } | |
1546 | ||
1547 | /** | |
1548 | Yields `true` if `R` has a `length` member that returns a value of `size_t` | |
1549 | type. `R` does not have to be a range. If `R` is a range, algorithms in the | |
1550 | standard library are only guaranteed to support `length` with type `size_t`. | |
1551 | ||
1552 | Note that `length` is an optional primitive as no range must implement it. Some | |
1553 | ranges do not store their length explicitly, some cannot compute it without | |
1554 | actually exhausting the range (e.g. socket streams), and some other ranges may | |
1555 | be infinite. | |
1556 | ||
1557 | Although narrow string types (`char[]`, `wchar[]`, and their qualified | |
1558 | derivatives) do define a `length` property, `hasLength` yields `false` for them. | |
1559 | This is because a narrow string's length does not reflect the number of | |
1560 | characters, but instead the number of encoding units, and as such is not useful | |
1561 | with range-oriented algorithms. To use strings as random-access ranges with | |
1562 | length, use $(REF representation, std, string) or $(REF byCodeUnit, std, utf). | |
b4c522fa IB |
1563 | */ |
1564 | template hasLength(R) | |
1565 | { | |
1566 | static if (is(typeof(((R* r) => r.length)(null)) Length)) | |
5fee5ec3 IB |
1567 | enum bool hasLength = is(Length == size_t) && |
1568 | !(isAutodecodableString!R && !isAggregateType!R); | |
b4c522fa | 1569 | else |
b4c522fa | 1570 | enum bool hasLength = false; |
b4c522fa IB |
1571 | } |
1572 | ||
1573 | /// | |
1574 | @safe unittest | |
1575 | { | |
1576 | static assert(!hasLength!(char[])); | |
1577 | static assert( hasLength!(int[])); | |
1578 | static assert( hasLength!(inout(int)[])); | |
1579 | ||
9fa27ed0 IB |
1580 | struct A { size_t length() { return 0; } } |
1581 | struct B { @property size_t length() { return 0; } } | |
b4c522fa IB |
1582 | static assert( hasLength!(A)); |
1583 | static assert( hasLength!(B)); | |
9fa27ed0 IB |
1584 | } |
1585 | ||
1586 | // test combinations which are invalid on some platforms | |
5fee5ec3 | 1587 | @safe unittest |
9fa27ed0 IB |
1588 | { |
1589 | struct A { ulong length; } | |
1590 | struct B { @property uint length() { return 0; } } | |
1591 | ||
fc186077 | 1592 | static if (is(size_t == uint)) |
9fa27ed0 IB |
1593 | { |
1594 | static assert(!hasLength!(A)); | |
1595 | static assert(hasLength!(B)); | |
1596 | } | |
fc186077 | 1597 | else static if (is(size_t == ulong)) |
9fa27ed0 IB |
1598 | { |
1599 | static assert(hasLength!(A)); | |
1600 | static assert(!hasLength!(B)); | |
1601 | } | |
1602 | } | |
1603 | ||
1604 | // test combinations which are invalid on all platforms | |
5fee5ec3 | 1605 | @safe unittest |
9fa27ed0 IB |
1606 | { |
1607 | struct A { long length; } | |
1608 | struct B { int length; } | |
1609 | struct C { ubyte length; } | |
1610 | struct D { char length; } | |
1611 | static assert(!hasLength!(A)); | |
1612 | static assert(!hasLength!(B)); | |
1613 | static assert(!hasLength!(C)); | |
1614 | static assert(!hasLength!(D)); | |
b4c522fa IB |
1615 | } |
1616 | ||
1617 | /** | |
5fee5ec3 | 1618 | Returns `true` if `R` is an infinite input range. An |
b4c522fa | 1619 | infinite input range is an input range that has a statically-defined |
5fee5ec3 | 1620 | enumerated member called `empty` that is always `false`, |
b4c522fa IB |
1621 | for example: |
1622 | ||
1623 | ---- | |
1624 | struct MyInfiniteRange | |
1625 | { | |
1626 | enum bool empty = false; | |
1627 | ... | |
1628 | } | |
1629 | ---- | |
1630 | */ | |
1631 | ||
1632 | template isInfinite(R) | |
1633 | { | |
1634 | static if (isInputRange!R && __traits(compiles, { enum e = R.empty; })) | |
1635 | enum bool isInfinite = !R.empty; | |
1636 | else | |
1637 | enum bool isInfinite = false; | |
1638 | } | |
1639 | ||
1640 | /// | |
1641 | @safe unittest | |
1642 | { | |
1643 | import std.range : Repeat; | |
1644 | static assert(!isInfinite!(int[])); | |
1645 | static assert( isInfinite!(Repeat!(int))); | |
1646 | } | |
1647 | ||
1648 | /** | |
5fee5ec3 | 1649 | Returns `true` if `R` offers a slicing operator with integral boundaries |
b4c522fa IB |
1650 | that returns a forward range type. |
1651 | ||
5fee5ec3 IB |
1652 | For finite ranges, the result of `opSlice` must be of the same type as the |
1653 | original range type. If the range defines `opDollar`, then it must support | |
b4c522fa IB |
1654 | subtraction. |
1655 | ||
5fee5ec3 IB |
1656 | For infinite ranges, when $(I not) using `opDollar`, the result of |
1657 | `opSlice` must be the result of $(LREF take) or $(LREF takeExactly) on the | |
b4c522fa | 1658 | original range (they both return the same type for infinite ranges). However, |
5fee5ec3 | 1659 | when using `opDollar`, the result of `opSlice` must be that of the |
b4c522fa IB |
1660 | original range type. |
1661 | ||
1662 | The following expression must be true for `hasSlicing` to be `true`: | |
1663 | ||
1664 | ---- | |
1665 | isForwardRange!R | |
1666 | && !isNarrowString!R | |
1667 | && is(ReturnType!((R r) => r[1 .. 1].length) == size_t) | |
1668 | && (is(typeof(lvalueOf!R[1 .. 1]) == R) || isInfinite!R) | |
1669 | && (!is(typeof(lvalueOf!R[0 .. $])) || is(typeof(lvalueOf!R[0 .. $]) == R)) | |
1670 | && (!is(typeof(lvalueOf!R[0 .. $])) || isInfinite!R | |
1671 | || is(typeof(lvalueOf!R[0 .. $ - 1]) == R)) | |
1672 | && is(typeof((ref R r) | |
1673 | { | |
1674 | static assert(isForwardRange!(typeof(r[1 .. 2]))); | |
1675 | })); | |
1676 | ---- | |
1677 | */ | |
1678 | enum bool hasSlicing(R) = isForwardRange!R | |
5fee5ec3 | 1679 | && !(isAutodecodableString!R && !isAggregateType!R) |
b4c522fa IB |
1680 | && is(ReturnType!((R r) => r[1 .. 1].length) == size_t) |
1681 | && (is(typeof(lvalueOf!R[1 .. 1]) == R) || isInfinite!R) | |
1682 | && (!is(typeof(lvalueOf!R[0 .. $])) || is(typeof(lvalueOf!R[0 .. $]) == R)) | |
1683 | && (!is(typeof(lvalueOf!R[0 .. $])) || isInfinite!R | |
1684 | || is(typeof(lvalueOf!R[0 .. $ - 1]) == R)) | |
1685 | && is(typeof((ref R r) | |
1686 | { | |
1687 | static assert(isForwardRange!(typeof(r[1 .. 2]))); | |
1688 | })); | |
1689 | ||
1690 | /// | |
1691 | @safe unittest | |
1692 | { | |
1693 | import std.range : takeExactly; | |
1694 | static assert( hasSlicing!(int[])); | |
1695 | static assert( hasSlicing!(const(int)[])); | |
1696 | static assert(!hasSlicing!(const int[])); | |
1697 | static assert( hasSlicing!(inout(int)[])); | |
1698 | static assert(!hasSlicing!(inout int [])); | |
1699 | static assert( hasSlicing!(immutable(int)[])); | |
1700 | static assert(!hasSlicing!(immutable int[])); | |
1701 | static assert(!hasSlicing!string); | |
1702 | static assert( hasSlicing!dstring); | |
1703 | ||
1704 | enum rangeFuncs = "@property int front();" ~ | |
1705 | "void popFront();" ~ | |
1706 | "@property bool empty();" ~ | |
1707 | "@property auto save() { return this; }" ~ | |
1708 | "@property size_t length();"; | |
1709 | ||
1710 | struct A { mixin(rangeFuncs); int opSlice(size_t, size_t); } | |
1711 | struct B { mixin(rangeFuncs); B opSlice(size_t, size_t); } | |
1712 | struct C { mixin(rangeFuncs); @disable this(); C opSlice(size_t, size_t); } | |
1713 | struct D { mixin(rangeFuncs); int[] opSlice(size_t, size_t); } | |
1714 | static assert(!hasSlicing!(A)); | |
1715 | static assert( hasSlicing!(B)); | |
1716 | static assert( hasSlicing!(C)); | |
1717 | static assert(!hasSlicing!(D)); | |
1718 | ||
1719 | struct InfOnes | |
1720 | { | |
1721 | enum empty = false; | |
1722 | void popFront() {} | |
1723 | @property int front() { return 1; } | |
1724 | @property InfOnes save() { return this; } | |
1725 | auto opSlice(size_t i, size_t j) { return takeExactly(this, j - i); } | |
1726 | auto opSlice(size_t i, Dollar d) { return this; } | |
1727 | ||
1728 | struct Dollar {} | |
1729 | Dollar opDollar() const { return Dollar.init; } | |
1730 | } | |
1731 | ||
1732 | static assert(hasSlicing!InfOnes); | |
1733 | } | |
1734 | ||
1735 | /** | |
5fee5ec3 | 1736 | This is a best-effort implementation of `length` for any kind of |
b4c522fa IB |
1737 | range. |
1738 | ||
5fee5ec3 IB |
1739 | If `hasLength!Range`, simply returns `range.length` without |
1740 | checking `upTo` (when specified). | |
b4c522fa IB |
1741 | |
1742 | Otherwise, walks the range through its length and returns the number | |
5fee5ec3 IB |
1743 | of elements seen. Performes $(BIGOH n) evaluations of `range.empty` |
1744 | and `range.popFront()`, where `n` is the effective length of $(D | |
b4c522fa IB |
1745 | range). |
1746 | ||
5fee5ec3 | 1747 | The `upTo` parameter is useful to "cut the losses" in case |
b4c522fa | 1748 | the interest is in seeing whether the range has at least some number |
5fee5ec3 IB |
1749 | of elements. If the parameter `upTo` is specified, stops if $(D |
1750 | upTo) steps have been taken and returns `upTo`. | |
b4c522fa | 1751 | |
5fee5ec3 | 1752 | Infinite ranges are compatible, provided the parameter `upTo` is |
b4c522fa IB |
1753 | specified, in which case the implementation simply returns upTo. |
1754 | */ | |
1755 | auto walkLength(Range)(Range range) | |
1756 | if (isInputRange!Range && !isInfinite!Range) | |
1757 | { | |
1758 | static if (hasLength!Range) | |
1759 | return range.length; | |
1760 | else | |
1761 | { | |
1762 | size_t result; | |
5fee5ec3 IB |
1763 | static if (autodecodeStrings && isNarrowString!Range) |
1764 | { | |
1765 | import std.utf : codeUnitLimit; | |
1766 | result = range.length; | |
1767 | foreach (const i, const c; range) | |
1768 | { | |
1769 | if (c >= codeUnitLimit!Range) | |
1770 | { | |
1771 | result = i; | |
1772 | break; | |
1773 | } | |
1774 | } | |
1775 | range = range[result .. $]; | |
1776 | } | |
b4c522fa IB |
1777 | for ( ; !range.empty ; range.popFront() ) |
1778 | ++result; | |
1779 | return result; | |
1780 | } | |
1781 | } | |
1782 | /// ditto | |
1783 | auto walkLength(Range)(Range range, const size_t upTo) | |
1784 | if (isInputRange!Range) | |
1785 | { | |
1786 | static if (hasLength!Range) | |
1787 | return range.length; | |
1788 | else static if (isInfinite!Range) | |
1789 | return upTo; | |
1790 | else | |
1791 | { | |
1792 | size_t result; | |
5fee5ec3 IB |
1793 | static if (autodecodeStrings && isNarrowString!Range) |
1794 | { | |
1795 | import std.utf : codeUnitLimit; | |
1796 | result = upTo > range.length ? range.length : upTo; | |
1797 | foreach (const i, const c; range[0 .. result]) | |
1798 | { | |
1799 | if (c >= codeUnitLimit!Range) | |
1800 | { | |
1801 | result = i; | |
1802 | break; | |
1803 | } | |
1804 | } | |
1805 | range = range[result .. $]; | |
1806 | } | |
b4c522fa IB |
1807 | for ( ; result < upTo && !range.empty ; range.popFront() ) |
1808 | ++result; | |
1809 | return result; | |
1810 | } | |
1811 | } | |
1812 | ||
5fee5ec3 IB |
1813 | /// |
1814 | @safe unittest | |
1815 | { | |
1816 | import std.range : iota; | |
1817 | ||
1818 | assert(10.iota.walkLength == 10); | |
1819 | // iota has a length function, and therefore the | |
1820 | // doesn't have to be walked, and the upTo | |
1821 | // parameter is ignored | |
1822 | assert(10.iota.walkLength(5) == 10); | |
1823 | } | |
1824 | ||
b4c522fa IB |
1825 | @safe unittest |
1826 | { | |
1827 | import std.algorithm.iteration : filter; | |
1828 | import std.range : recurrence, take; | |
1829 | ||
1830 | //hasLength Range | |
1831 | int[] a = [ 1, 2, 3 ]; | |
1832 | assert(walkLength(a) == 3); | |
1833 | assert(walkLength(a, 0) == 3); | |
1834 | assert(walkLength(a, 2) == 3); | |
1835 | assert(walkLength(a, 4) == 3); | |
1836 | ||
1837 | //Forward Range | |
1838 | auto b = filter!"true"([1, 2, 3, 4]); | |
1839 | assert(b.walkLength() == 4); | |
1840 | assert(b.walkLength(0) == 0); | |
1841 | assert(b.walkLength(2) == 2); | |
1842 | assert(b.walkLength(4) == 4); | |
1843 | assert(b.walkLength(6) == 4); | |
1844 | ||
1845 | //Infinite Range | |
1846 | auto fibs = recurrence!"a[n-1] + a[n-2]"(1, 1); | |
1847 | assert(!__traits(compiles, fibs.walkLength())); | |
1848 | assert(fibs.take(10).walkLength() == 10); | |
1849 | assert(fibs.walkLength(55) == 55); | |
1850 | } | |
1851 | ||
1852 | /** | |
5fee5ec3 IB |
1853 | `popFrontN` eagerly advances `r` itself (not a copy) up to `n` times |
1854 | (by calling `r.popFront`). `popFrontN` takes `r` by `ref`, | |
b4c522fa IB |
1855 | so it mutates the original range. Completes in $(BIGOH 1) steps for ranges |
1856 | that support slicing and have length. | |
1857 | Completes in $(BIGOH n) time for all other ranges. | |
1858 | ||
5fee5ec3 IB |
1859 | `popBackN` behaves the same as `popFrontN` but instead removes |
1860 | elements from the back of the (bidirectional) range instead of the front. | |
b4c522fa | 1861 | |
5fee5ec3 IB |
1862 | Returns: |
1863 | How much `r` was actually advanced, which may be less than `n` if | |
1864 | `r` did not have at least `n` elements. | |
b4c522fa IB |
1865 | |
1866 | See_Also: $(REF drop, std, range), $(REF dropBack, std, range) | |
1867 | */ | |
1868 | size_t popFrontN(Range)(ref Range r, size_t n) | |
1869 | if (isInputRange!Range) | |
1870 | { | |
1871 | static if (hasLength!Range) | |
1872 | { | |
1873 | n = cast(size_t) (n < r.length ? n : r.length); | |
1874 | } | |
1875 | ||
1876 | static if (hasSlicing!Range && is(typeof(r = r[n .. $]))) | |
1877 | { | |
1878 | r = r[n .. $]; | |
1879 | } | |
1880 | else static if (hasSlicing!Range && hasLength!Range) //TODO: Remove once hasSlicing forces opDollar. | |
1881 | { | |
1882 | r = r[n .. r.length]; | |
1883 | } | |
1884 | else | |
1885 | { | |
1886 | static if (hasLength!Range) | |
1887 | { | |
1888 | foreach (i; 0 .. n) | |
1889 | r.popFront(); | |
1890 | } | |
1891 | else | |
1892 | { | |
1893 | foreach (i; 0 .. n) | |
1894 | { | |
1895 | if (r.empty) return i; | |
1896 | r.popFront(); | |
1897 | } | |
1898 | } | |
1899 | } | |
1900 | return n; | |
1901 | } | |
1902 | ||
1903 | /// ditto | |
1904 | size_t popBackN(Range)(ref Range r, size_t n) | |
1905 | if (isBidirectionalRange!Range) | |
1906 | { | |
1907 | static if (hasLength!Range) | |
1908 | { | |
1909 | n = cast(size_t) (n < r.length ? n : r.length); | |
1910 | } | |
1911 | ||
1912 | static if (hasSlicing!Range && is(typeof(r = r[0 .. $ - n]))) | |
1913 | { | |
1914 | r = r[0 .. $ - n]; | |
1915 | } | |
1916 | else static if (hasSlicing!Range && hasLength!Range) //TODO: Remove once hasSlicing forces opDollar. | |
1917 | { | |
1918 | r = r[0 .. r.length - n]; | |
1919 | } | |
1920 | else | |
1921 | { | |
1922 | static if (hasLength!Range) | |
1923 | { | |
1924 | foreach (i; 0 .. n) | |
1925 | r.popBack(); | |
1926 | } | |
1927 | else | |
1928 | { | |
1929 | foreach (i; 0 .. n) | |
1930 | { | |
1931 | if (r.empty) return i; | |
1932 | r.popBack(); | |
1933 | } | |
1934 | } | |
1935 | } | |
1936 | return n; | |
1937 | } | |
1938 | ||
1939 | /// | |
1940 | @safe unittest | |
1941 | { | |
1942 | int[] a = [ 1, 2, 3, 4, 5 ]; | |
1943 | a.popFrontN(2); | |
1944 | assert(a == [ 3, 4, 5 ]); | |
1945 | a.popFrontN(7); | |
1946 | assert(a == [ ]); | |
1947 | } | |
1948 | ||
1949 | /// | |
1950 | @safe unittest | |
1951 | { | |
1952 | import std.algorithm.comparison : equal; | |
1953 | import std.range : iota; | |
1954 | auto LL = iota(1L, 7L); | |
1955 | auto r = popFrontN(LL, 2); | |
1956 | assert(equal(LL, [3L, 4L, 5L, 6L])); | |
1957 | assert(r == 2); | |
1958 | } | |
1959 | ||
1960 | /// | |
1961 | @safe unittest | |
1962 | { | |
1963 | int[] a = [ 1, 2, 3, 4, 5 ]; | |
1964 | a.popBackN(2); | |
1965 | assert(a == [ 1, 2, 3 ]); | |
1966 | a.popBackN(7); | |
1967 | assert(a == [ ]); | |
1968 | } | |
1969 | ||
1970 | /// | |
1971 | @safe unittest | |
1972 | { | |
1973 | import std.algorithm.comparison : equal; | |
1974 | import std.range : iota; | |
1975 | auto LL = iota(1L, 7L); | |
1976 | auto r = popBackN(LL, 2); | |
1977 | assert(equal(LL, [1L, 2L, 3L, 4L])); | |
1978 | assert(r == 2); | |
1979 | } | |
1980 | ||
1981 | /** | |
5fee5ec3 IB |
1982 | Eagerly advances `r` itself (not a copy) exactly `n` times (by |
1983 | calling `r.popFront`). `popFrontExactly` takes `r` by `ref`, | |
b4c522fa IB |
1984 | so it mutates the original range. Completes in $(BIGOH 1) steps for ranges |
1985 | that support slicing, and have either length or are infinite. | |
1986 | Completes in $(BIGOH n) time for all other ranges. | |
1987 | ||
5fee5ec3 IB |
1988 | Note: Unlike $(LREF popFrontN), `popFrontExactly` will assume that the |
1989 | range holds at least `n` elements. This makes `popFrontExactly` | |
1990 | faster than `popFrontN`, but it also means that if `range` does | |
1991 | not contain at least `n` elements, it will attempt to call `popFront` | |
b4c522fa | 1992 | on an empty range, which is undefined behavior. So, only use |
5fee5ec3 IB |
1993 | `popFrontExactly` when it is guaranteed that `range` holds at least |
1994 | `n` elements. | |
b4c522fa | 1995 | |
5fee5ec3 | 1996 | `popBackExactly` will behave the same but instead removes elements from |
b4c522fa IB |
1997 | the back of the (bidirectional) range instead of the front. |
1998 | ||
5fee5ec3 | 1999 | See_Also: $(REF dropExactly, std, range), $(REF dropBackExactly, std, range) |
b4c522fa IB |
2000 | */ |
2001 | void popFrontExactly(Range)(ref Range r, size_t n) | |
2002 | if (isInputRange!Range) | |
2003 | { | |
2004 | static if (hasLength!Range) | |
2005 | assert(n <= r.length, "range is smaller than amount of items to pop"); | |
2006 | ||
2007 | static if (hasSlicing!Range && is(typeof(r = r[n .. $]))) | |
2008 | r = r[n .. $]; | |
2009 | else static if (hasSlicing!Range && hasLength!Range) //TODO: Remove once hasSlicing forces opDollar. | |
2010 | r = r[n .. r.length]; | |
2011 | else | |
2012 | foreach (i; 0 .. n) | |
2013 | r.popFront(); | |
2014 | } | |
2015 | ||
2016 | /// ditto | |
2017 | void popBackExactly(Range)(ref Range r, size_t n) | |
2018 | if (isBidirectionalRange!Range) | |
2019 | { | |
2020 | static if (hasLength!Range) | |
2021 | assert(n <= r.length, "range is smaller than amount of items to pop"); | |
2022 | ||
2023 | static if (hasSlicing!Range && is(typeof(r = r[0 .. $ - n]))) | |
2024 | r = r[0 .. $ - n]; | |
2025 | else static if (hasSlicing!Range && hasLength!Range) //TODO: Remove once hasSlicing forces opDollar. | |
2026 | r = r[0 .. r.length - n]; | |
2027 | else | |
2028 | foreach (i; 0 .. n) | |
2029 | r.popBack(); | |
2030 | } | |
2031 | ||
2032 | /// | |
2033 | @safe unittest | |
2034 | { | |
2035 | import std.algorithm.comparison : equal; | |
2036 | import std.algorithm.iteration : filterBidirectional; | |
2037 | ||
2038 | auto a = [1, 2, 3]; | |
2039 | a.popFrontExactly(1); | |
2040 | assert(a == [2, 3]); | |
2041 | a.popBackExactly(1); | |
2042 | assert(a == [2]); | |
2043 | ||
2044 | string s = "日本語"; | |
2045 | s.popFrontExactly(1); | |
2046 | assert(s == "本語"); | |
2047 | s.popBackExactly(1); | |
2048 | assert(s == "本"); | |
2049 | ||
2050 | auto bd = filterBidirectional!"true"([1, 2, 3]); | |
2051 | bd.popFrontExactly(1); | |
2052 | assert(bd.equal([2, 3])); | |
2053 | bd.popBackExactly(1); | |
2054 | assert(bd.equal([2])); | |
2055 | } | |
2056 | ||
2057 | /** | |
5fee5ec3 | 2058 | Moves the front of `r` out and returns it. Leaves `r.front` in a |
b4c522fa | 2059 | destroyable state that does not allocate any resources (usually equal |
5fee5ec3 | 2060 | to its `.init` value). |
b4c522fa IB |
2061 | */ |
2062 | ElementType!R moveFront(R)(R r) | |
2063 | { | |
2064 | static if (is(typeof(&r.moveFront))) | |
2065 | { | |
2066 | return r.moveFront(); | |
2067 | } | |
2068 | else static if (!hasElaborateCopyConstructor!(ElementType!R)) | |
2069 | { | |
2070 | return r.front; | |
2071 | } | |
2072 | else static if (is(typeof(&(r.front())) == ElementType!R*)) | |
2073 | { | |
2074 | import std.algorithm.mutation : move; | |
2075 | return move(r.front); | |
2076 | } | |
2077 | else | |
2078 | { | |
2079 | static assert(0, | |
2080 | "Cannot move front of a range with a postblit and an rvalue front."); | |
2081 | } | |
2082 | } | |
2083 | ||
2084 | /// | |
2085 | @safe unittest | |
2086 | { | |
2087 | auto a = [ 1, 2, 3 ]; | |
2088 | assert(moveFront(a) == 1); | |
2089 | assert(a.length == 3); | |
2090 | ||
2091 | // define a perfunctory input range | |
2092 | struct InputRange | |
2093 | { | |
2094 | enum bool empty = false; | |
2095 | enum int front = 7; | |
2096 | void popFront() {} | |
2097 | int moveFront() { return 43; } | |
2098 | } | |
2099 | InputRange r; | |
2100 | // calls r.moveFront | |
2101 | assert(moveFront(r) == 43); | |
2102 | } | |
2103 | ||
2104 | @safe unittest | |
2105 | { | |
2106 | struct R | |
2107 | { | |
2108 | @property ref int front() { static int x = 42; return x; } | |
2109 | this(this){} | |
2110 | } | |
2111 | R r; | |
2112 | assert(moveFront(r) == 42); | |
2113 | } | |
2114 | ||
2115 | /** | |
5fee5ec3 | 2116 | Moves the back of `r` out and returns it. Leaves `r.back` in a |
b4c522fa | 2117 | destroyable state that does not allocate any resources (usually equal |
5fee5ec3 | 2118 | to its `.init` value). |
b4c522fa IB |
2119 | */ |
2120 | ElementType!R moveBack(R)(R r) | |
2121 | { | |
2122 | static if (is(typeof(&r.moveBack))) | |
2123 | { | |
2124 | return r.moveBack(); | |
2125 | } | |
2126 | else static if (!hasElaborateCopyConstructor!(ElementType!R)) | |
2127 | { | |
2128 | return r.back; | |
2129 | } | |
2130 | else static if (is(typeof(&(r.back())) == ElementType!R*)) | |
2131 | { | |
2132 | import std.algorithm.mutation : move; | |
2133 | return move(r.back); | |
2134 | } | |
2135 | else | |
2136 | { | |
2137 | static assert(0, | |
2138 | "Cannot move back of a range with a postblit and an rvalue back."); | |
2139 | } | |
2140 | } | |
2141 | ||
2142 | /// | |
2143 | @safe unittest | |
2144 | { | |
2145 | struct TestRange | |
2146 | { | |
2147 | int payload = 5; | |
2148 | @property bool empty() { return false; } | |
2149 | @property TestRange save() { return this; } | |
2150 | @property ref int front() return { return payload; } | |
2151 | @property ref int back() return { return payload; } | |
2152 | void popFront() { } | |
2153 | void popBack() { } | |
2154 | } | |
2155 | static assert(isBidirectionalRange!TestRange); | |
2156 | TestRange r; | |
2157 | auto x = moveBack(r); | |
2158 | assert(x == 5); | |
2159 | } | |
2160 | ||
2161 | /** | |
5fee5ec3 | 2162 | Moves element at index `i` of `r` out and returns it. Leaves $(D |
b4c522fa | 2163 | r[i]) in a destroyable state that does not allocate any resources |
5fee5ec3 | 2164 | (usually equal to its `.init` value). |
b4c522fa IB |
2165 | */ |
2166 | ElementType!R moveAt(R)(R r, size_t i) | |
2167 | { | |
2168 | static if (is(typeof(&r.moveAt))) | |
2169 | { | |
2170 | return r.moveAt(i); | |
2171 | } | |
2172 | else static if (!hasElaborateCopyConstructor!(ElementType!(R))) | |
2173 | { | |
2174 | return r[i]; | |
2175 | } | |
2176 | else static if (is(typeof(&r[i]) == ElementType!R*)) | |
2177 | { | |
2178 | import std.algorithm.mutation : move; | |
2179 | return move(r[i]); | |
2180 | } | |
2181 | else | |
2182 | { | |
2183 | static assert(0, | |
2184 | "Cannot move element of a range with a postblit and rvalue elements."); | |
2185 | } | |
2186 | } | |
2187 | ||
2188 | /// | |
2189 | @safe unittest | |
2190 | { | |
2191 | auto a = [1,2,3,4]; | |
2192 | foreach (idx, it; a) | |
2193 | { | |
2194 | assert(it == moveAt(a, idx)); | |
2195 | } | |
2196 | } | |
2197 | ||
2198 | @safe unittest | |
2199 | { | |
2200 | import std.internal.test.dummyrange; | |
2201 | ||
2202 | foreach (DummyType; AllDummyRanges) | |
2203 | { | |
2204 | auto d = DummyType.init; | |
2205 | assert(moveFront(d) == 1); | |
2206 | ||
2207 | static if (isBidirectionalRange!DummyType) | |
2208 | { | |
2209 | assert(moveBack(d) == 10); | |
2210 | } | |
2211 | ||
2212 | static if (isRandomAccessRange!DummyType) | |
2213 | { | |
2214 | assert(moveAt(d, 2) == 3); | |
2215 | } | |
2216 | } | |
2217 | } | |
2218 | ||
2219 | /** | |
5fee5ec3 IB |
2220 | Implements the range interface primitive `empty` for types that |
2221 | obey $(LREF hasLength) property and for narrow strings. Due to the | |
2222 | fact that nonmember functions can be called with the first argument | |
2223 | using the dot notation, `a.empty` is equivalent to `empty(a)`. | |
b4c522fa | 2224 | */ |
5fee5ec3 IB |
2225 | @property bool empty(T)(auto ref scope T a) |
2226 | if (is(typeof(a.length) : size_t)) | |
b4c522fa IB |
2227 | { |
2228 | return !a.length; | |
2229 | } | |
2230 | ||
2231 | /// | |
2232 | @safe pure nothrow unittest | |
2233 | { | |
2234 | auto a = [ 1, 2, 3 ]; | |
2235 | assert(!a.empty); | |
2236 | assert(a[3 .. $].empty); | |
5fee5ec3 IB |
2237 | |
2238 | int[string] b; | |
2239 | assert(b.empty); | |
2240 | b["zero"] = 0; | |
2241 | assert(!b.empty); | |
b4c522fa IB |
2242 | } |
2243 | ||
2244 | /** | |
5fee5ec3 | 2245 | Implements the range interface primitive `save` for built-in |
b4c522fa | 2246 | arrays. Due to the fact that nonmember functions can be called with |
5fee5ec3 IB |
2247 | the first argument using the dot notation, `array.save` is |
2248 | equivalent to `save(array)`. The function does not duplicate the | |
b4c522fa IB |
2249 | content of the array, it simply returns its argument. |
2250 | */ | |
5fee5ec3 | 2251 | @property inout(T)[] save(T)(return scope inout(T)[] a) @safe pure nothrow @nogc |
b4c522fa IB |
2252 | { |
2253 | return a; | |
2254 | } | |
2255 | ||
2256 | /// | |
2257 | @safe pure nothrow unittest | |
2258 | { | |
2259 | auto a = [ 1, 2, 3 ]; | |
2260 | auto b = a.save; | |
2261 | assert(b is a); | |
2262 | } | |
2263 | ||
2264 | /** | |
5fee5ec3 | 2265 | Implements the range interface primitive `popFront` for built-in |
b4c522fa | 2266 | arrays. Due to the fact that nonmember functions can be called with |
5fee5ec3 IB |
2267 | the first argument using the dot notation, `array.popFront` is |
2268 | equivalent to `popFront(array)`. For $(GLOSSARY narrow strings), | |
2269 | `popFront` automatically advances to the next $(GLOSSARY code | |
b4c522fa IB |
2270 | point). |
2271 | */ | |
5fee5ec3 IB |
2272 | void popFront(T)(scope ref inout(T)[] a) @safe pure nothrow @nogc |
2273 | if (!isAutodecodableString!(T[]) && !is(T[] == void[])) | |
b4c522fa IB |
2274 | { |
2275 | assert(a.length, "Attempting to popFront() past the end of an array of " ~ T.stringof); | |
2276 | a = a[1 .. $]; | |
2277 | } | |
2278 | ||
2279 | /// | |
2280 | @safe pure nothrow unittest | |
2281 | { | |
2282 | auto a = [ 1, 2, 3 ]; | |
2283 | a.popFront(); | |
2284 | assert(a == [ 2, 3 ]); | |
2285 | } | |
2286 | ||
5fee5ec3 | 2287 | @safe unittest |
b4c522fa IB |
2288 | { |
2289 | static assert(!is(typeof({ int[4] a; popFront(a); }))); | |
2290 | static assert(!is(typeof({ immutable int[] a; popFront(a); }))); | |
2291 | static assert(!is(typeof({ void[] a; popFront(a); }))); | |
2292 | } | |
2293 | ||
2294 | /// ditto | |
5fee5ec3 IB |
2295 | void popFront(C)(scope ref inout(C)[] str) @trusted pure nothrow |
2296 | if (isAutodecodableString!(C[])) | |
b4c522fa IB |
2297 | { |
2298 | import std.algorithm.comparison : min; | |
2299 | ||
2300 | assert(str.length, "Attempting to popFront() past the end of an array of " ~ C.stringof); | |
2301 | ||
5fee5ec3 | 2302 | static if (is(immutable C == immutable char)) |
b4c522fa IB |
2303 | { |
2304 | static immutable ubyte[] charWidthTab = [ | |
2305 | 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, | |
2306 | 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, | |
2307 | 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, | |
2308 | 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 1, 1 | |
2309 | ]; | |
2310 | ||
2311 | immutable c = str[0]; | |
5fee5ec3 IB |
2312 | immutable charWidth = c < 192 ? 1 : charWidthTab.ptr[c - 192]; |
2313 | str = str.ptr[min(str.length, charWidth) .. str.length]; | |
b4c522fa | 2314 | } |
5fee5ec3 | 2315 | else static if (is(immutable C == immutable wchar)) |
b4c522fa IB |
2316 | { |
2317 | immutable u = str[0]; | |
2318 | immutable seqLen = 1 + (u >= 0xD800 && u <= 0xDBFF); | |
2319 | str = str.ptr[min(seqLen, str.length) .. str.length]; | |
2320 | } | |
2321 | else static assert(0, "Bad template constraint."); | |
2322 | } | |
2323 | ||
2324 | @safe pure unittest | |
2325 | { | |
2326 | import std.meta : AliasSeq; | |
2327 | ||
5fee5ec3 IB |
2328 | static foreach (S; AliasSeq!(string, wstring, dstring)) |
2329 | {{ | |
b4c522fa IB |
2330 | S s = "\xC2\xA9hello"; |
2331 | s.popFront(); | |
2332 | assert(s == "hello"); | |
2333 | ||
2334 | S str = "hello\U00010143\u0100\U00010143"; | |
2335 | foreach (dchar c; ['h', 'e', 'l', 'l', 'o', '\U00010143', '\u0100', '\U00010143']) | |
2336 | { | |
2337 | assert(str.front == c); | |
2338 | str.popFront(); | |
2339 | } | |
2340 | assert(str.empty); | |
2341 | ||
2342 | static assert(!is(typeof({ immutable S a; popFront(a); }))); | |
2343 | static assert(!is(typeof({ typeof(S.init[0])[4] a; popFront(a); }))); | |
5fee5ec3 | 2344 | }} |
b4c522fa IB |
2345 | |
2346 | C[] _eatString(C)(C[] str) | |
2347 | { | |
2348 | while (!str.empty) | |
2349 | str.popFront(); | |
2350 | ||
2351 | return str; | |
2352 | } | |
2353 | enum checkCTFE = _eatString("ウェブサイト@La_Verité.com"); | |
2354 | static assert(checkCTFE.empty); | |
2355 | enum checkCTFEW = _eatString("ウェブサイト@La_Verité.com"w); | |
2356 | static assert(checkCTFEW.empty); | |
2357 | } | |
2358 | ||
5fee5ec3 IB |
2359 | // https://issues.dlang.org/show_bug.cgi?id=16090 |
2360 | @safe unittest | |
b4c522fa IB |
2361 | { |
2362 | string s = "\u00E4"; | |
2363 | assert(s.length == 2); | |
2364 | s = s[0 .. 1]; | |
2365 | assert(s.length == 1); | |
2366 | s.popFront; | |
2367 | assert(s.empty); | |
2368 | } | |
2369 | ||
2370 | @safe unittest | |
2371 | { | |
2372 | wstring s = "\U00010000"; | |
2373 | assert(s.length == 2); | |
2374 | s = s[0 .. 1]; | |
2375 | assert(s.length == 1); | |
2376 | s.popFront; | |
2377 | assert(s.empty); | |
2378 | } | |
2379 | ||
2380 | /** | |
5fee5ec3 | 2381 | Implements the range interface primitive `popBack` for built-in |
b4c522fa | 2382 | arrays. Due to the fact that nonmember functions can be called with |
5fee5ec3 IB |
2383 | the first argument using the dot notation, `array.popBack` is |
2384 | equivalent to `popBack(array)`. For $(GLOSSARY narrow strings), $(D | |
b4c522fa IB |
2385 | popFront) automatically eliminates the last $(GLOSSARY code point). |
2386 | */ | |
5fee5ec3 IB |
2387 | void popBack(T)(scope ref inout(T)[] a) @safe pure nothrow @nogc |
2388 | if (!isAutodecodableString!(T[]) && !is(T[] == void[])) | |
b4c522fa IB |
2389 | { |
2390 | assert(a.length); | |
2391 | a = a[0 .. $ - 1]; | |
2392 | } | |
2393 | ||
2394 | /// | |
2395 | @safe pure nothrow unittest | |
2396 | { | |
2397 | auto a = [ 1, 2, 3 ]; | |
2398 | a.popBack(); | |
2399 | assert(a == [ 1, 2 ]); | |
2400 | } | |
2401 | ||
5fee5ec3 | 2402 | @safe unittest |
b4c522fa IB |
2403 | { |
2404 | static assert(!is(typeof({ immutable int[] a; popBack(a); }))); | |
2405 | static assert(!is(typeof({ int[4] a; popBack(a); }))); | |
2406 | static assert(!is(typeof({ void[] a; popBack(a); }))); | |
2407 | } | |
2408 | ||
2409 | /// ditto | |
5fee5ec3 IB |
2410 | void popBack(T)(scope ref inout(T)[] a) @safe pure |
2411 | if (isAutodecodableString!(T[])) | |
b4c522fa IB |
2412 | { |
2413 | import std.utf : strideBack; | |
2414 | assert(a.length, "Attempting to popBack() past the front of an array of " ~ T.stringof); | |
2415 | a = a[0 .. $ - strideBack(a, $)]; | |
2416 | } | |
2417 | ||
2418 | @safe pure unittest | |
2419 | { | |
2420 | import std.meta : AliasSeq; | |
2421 | ||
5fee5ec3 IB |
2422 | static foreach (S; AliasSeq!(string, wstring, dstring)) |
2423 | {{ | |
b4c522fa IB |
2424 | S s = "hello\xE2\x89\xA0"; |
2425 | s.popBack(); | |
2426 | assert(s == "hello"); | |
2427 | S s3 = "\xE2\x89\xA0"; | |
2428 | auto c = s3.back; | |
2429 | assert(c == cast(dchar)'\u2260'); | |
2430 | s3.popBack(); | |
2431 | assert(s3 == ""); | |
2432 | ||
2433 | S str = "\U00010143\u0100\U00010143hello"; | |
2434 | foreach (dchar ch; ['o', 'l', 'l', 'e', 'h', '\U00010143', '\u0100', '\U00010143']) | |
2435 | { | |
2436 | assert(str.back == ch); | |
2437 | str.popBack(); | |
2438 | } | |
2439 | assert(str.empty); | |
2440 | ||
2441 | static assert(!is(typeof({ immutable S a; popBack(a); }))); | |
2442 | static assert(!is(typeof({ typeof(S.init[0])[4] a; popBack(a); }))); | |
5fee5ec3 | 2443 | }} |
b4c522fa IB |
2444 | } |
2445 | ||
2446 | /** | |
5fee5ec3 IB |
2447 | EXPERIMENTAL: to try out removing autodecoding, set the version |
2448 | `NoAutodecodeStrings`. Most things are expected to fail with this version | |
2449 | currently. | |
2450 | */ | |
2451 | version (NoAutodecodeStrings) | |
2452 | { | |
2453 | enum autodecodeStrings = false; | |
2454 | } | |
2455 | else | |
2456 | { | |
2457 | /// | |
2458 | enum autodecodeStrings = true; | |
2459 | } | |
2460 | ||
2461 | /** | |
2462 | Implements the range interface primitive `front` for built-in | |
b4c522fa | 2463 | arrays. Due to the fact that nonmember functions can be called with |
5fee5ec3 IB |
2464 | the first argument using the dot notation, `array.front` is |
2465 | equivalent to `front(array)`. For $(GLOSSARY narrow strings), $(D | |
b4c522fa IB |
2466 | front) automatically returns the first $(GLOSSARY code point) as _a $(D |
2467 | dchar). | |
2468 | */ | |
5fee5ec3 IB |
2469 | @property ref inout(T) front(T)(return scope inout(T)[] a) @safe pure nothrow @nogc |
2470 | if (!isAutodecodableString!(T[]) && !is(T[] == void[])) | |
b4c522fa IB |
2471 | { |
2472 | assert(a.length, "Attempting to fetch the front of an empty array of " ~ T.stringof); | |
2473 | return a[0]; | |
2474 | } | |
2475 | ||
2476 | /// | |
2477 | @safe pure nothrow unittest | |
2478 | { | |
2479 | int[] a = [ 1, 2, 3 ]; | |
2480 | assert(a.front == 1); | |
2481 | } | |
2482 | ||
2483 | @safe pure nothrow unittest | |
2484 | { | |
2485 | auto a = [ 1, 2 ]; | |
2486 | a.front = 4; | |
2487 | assert(a.front == 4); | |
2488 | assert(a == [ 4, 2 ]); | |
2489 | ||
2490 | immutable b = [ 1, 2 ]; | |
2491 | assert(b.front == 1); | |
2492 | ||
2493 | int[2] c = [ 1, 2 ]; | |
2494 | assert(c.front == 1); | |
2495 | } | |
2496 | ||
2497 | /// ditto | |
5fee5ec3 IB |
2498 | @property dchar front(T)(scope const(T)[] a) @safe pure |
2499 | if (isAutodecodableString!(T[])) | |
b4c522fa IB |
2500 | { |
2501 | import std.utf : decode; | |
2502 | assert(a.length, "Attempting to fetch the front of an empty array of " ~ T.stringof); | |
2503 | size_t i = 0; | |
2504 | return decode(a, i); | |
2505 | } | |
2506 | ||
2507 | /** | |
5fee5ec3 | 2508 | Implements the range interface primitive `back` for built-in |
b4c522fa | 2509 | arrays. Due to the fact that nonmember functions can be called with |
5fee5ec3 IB |
2510 | the first argument using the dot notation, `array.back` is |
2511 | equivalent to `back(array)`. For $(GLOSSARY narrow strings), $(D | |
b4c522fa IB |
2512 | back) automatically returns the last $(GLOSSARY code point) as _a $(D |
2513 | dchar). | |
2514 | */ | |
5fee5ec3 IB |
2515 | @property ref inout(T) back(T)(return scope inout(T)[] a) @safe pure nothrow @nogc |
2516 | if (!isAutodecodableString!(T[]) && !is(T[] == void[])) | |
b4c522fa IB |
2517 | { |
2518 | assert(a.length, "Attempting to fetch the back of an empty array of " ~ T.stringof); | |
2519 | return a[$ - 1]; | |
2520 | } | |
2521 | ||
2522 | /// | |
2523 | @safe pure nothrow unittest | |
2524 | { | |
2525 | int[] a = [ 1, 2, 3 ]; | |
2526 | assert(a.back == 3); | |
2527 | a.back += 4; | |
2528 | assert(a.back == 7); | |
2529 | } | |
2530 | ||
2531 | @safe pure nothrow unittest | |
2532 | { | |
2533 | immutable b = [ 1, 2, 3 ]; | |
2534 | assert(b.back == 3); | |
2535 | ||
2536 | int[3] c = [ 1, 2, 3 ]; | |
2537 | assert(c.back == 3); | |
2538 | } | |
2539 | ||
2540 | /// ditto | |
2541 | // Specialization for strings | |
5fee5ec3 IB |
2542 | @property dchar back(T)(scope const(T)[] a) @safe pure |
2543 | if (isAutodecodableString!(T[])) | |
b4c522fa IB |
2544 | { |
2545 | import std.utf : decode, strideBack; | |
2546 | assert(a.length, "Attempting to fetch the back of an empty array of " ~ T.stringof); | |
2547 | size_t i = a.length - strideBack(a, a.length); | |
2548 | return decode(a, i); | |
2549 | } | |
5fee5ec3 IB |
2550 | |
2551 | /* | |
2552 | Implements `length` for a range by forwarding it to `member`. | |
2553 | */ | |
2554 | package(std) mixin template ImplementLength(alias member) | |
2555 | { | |
2556 | static if (hasLength!(typeof(member))) | |
2557 | { | |
2558 | @property auto length() | |
2559 | { | |
2560 | return member.length; | |
2561 | } | |
2562 | alias opDollar = length; | |
2563 | } | |
2564 | } |