userdiff: add support for Scheme

Add a diff driver for Scheme-like languages which recognizes top level
and local `define` forms, whether it is a function definition, binding,
syntax definition or a user-defined `define-xyzzy` form.

Also supports R6RS `library` forms, `module` forms along with class and
struct declarations used in Racket (PLT Scheme).

Alternate "def" syntax such as those in Gerbil Scheme are also
supported, like defstruct, defsyntax and so on.

The rationale for picking `define` forms for the hunk headers is because
it is usually the only significant form for defining the structure of
the program, and it is a common pattern for schemers to have local
function definitions to hide their visibility, so it is not only the top
level `define`'s that are of interest. Schemers also extend the language
with macros to provide their own define forms (for example, something
like a `define-test-suite`) which is also captured in the hunk header.

Since it is common practice to extend syntax with variants of a form
like `module+`, `class*` etc, those have been supported as well.

The word regex is a best-effort attempt to conform to R7RS[1] valid
identifiers, symbols and numbers.

[1] https://small.r7rs.org/attachment/r7rs.pdf (section 2.1)

Signed-off-by: Atharva Raykar <raykar.ath@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index 0a60472bb599fa5cbaecd37cc75f959e75c0078f..cfcfa800c2d05743fe503138f33e93e2ac521500 100644 (file)
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -845,6 +845,8 @@ patterns are available:
 
 - `rust` suitable for source code in the Rust language.
 
+- `scheme` suitable for source code in the Scheme language.
+
 - `tex` suitable for source code for LaTeX documents.
 
 

diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
index 9675bc17db276a51b1c5dc1b64ff1e94e1b0fc09..823ea96acba4fd67c4ce7f84838be41e06380d89 100755 (executable)
--- a/t/t4018-diff-funcname.sh
+++ b/t/t4018-diff-funcname.sh
@@ -48,6 +48,7 @@ diffpatterns="
        python
        ruby
        rust
+       scheme
        tex
        custom1
        custom2

diff --git a/t/t4018/scheme-class b/t/t4018/scheme-class
new file mode 100644 (file)
index 0000000..e5e07b4
--- /dev/null
+++ b/t/t4018/scheme-class
@@ -0,0 +1,7 @@
+(define book-class%
+  (class* () object% RIGHT
+    (field (pages 5))
+    (field (ChangeMe 5))
+    (define/public (letters)
+      (* pages 500))
+    (super-new)))

diff --git a/t/t4018/scheme-def b/t/t4018/scheme-def
new file mode 100644 (file)
index 0000000..1e2673d
--- /dev/null
+++ b/t/t4018/scheme-def
@@ -0,0 +1,4 @@
+(def (some-func x y z) RIGHT
+  (let ((a x)
+        (b y))
+        (ChangeMe a b)))

diff --git a/t/t4018/scheme-def-variant b/t/t4018/scheme-def-variant
new file mode 100644 (file)
index 0000000..d857a61
--- /dev/null
+++ b/t/t4018/scheme-def-variant
@@ -0,0 +1,4 @@
+(defmethod {print point} RIGHT
+  (lambda (self)
+    (with ((point x y) self)
+      (printf "{ChangeMe x:~a y:~a}~n" x y))))

diff --git a/t/t4018/scheme-define-slash-public b/t/t4018/scheme-define-slash-public
new file mode 100644 (file)
index 0000000..39a93a1
--- /dev/null
+++ b/t/t4018/scheme-define-slash-public
@@ -0,0 +1,7 @@
+(define bar-class%
+  (class object%
+    (field (info 5))
+    (define/public (foo) RIGHT
+      (+ info 42)
+      (* info ChangeMe))
+    (super-new)))

diff --git a/t/t4018/scheme-define-syntax b/t/t4018/scheme-define-syntax
new file mode 100644 (file)
index 0000000..7d5e99e
--- /dev/null
+++ b/t/t4018/scheme-define-syntax
@@ -0,0 +1,8 @@
+(define-syntax define-test-suite RIGHT
+  (syntax-rules ()
+    ((_ suite-name (name test) ChangeMe ...)
+     (define suite-name
+       (let ((tests
+              `((name . ,test) ...)))
+         (lambda ()
+           (run-suite 'suite-name tests)))))))

diff --git a/t/t4018/scheme-define-variant b/t/t4018/scheme-define-variant
new file mode 100644 (file)
index 0000000..9117088
--- /dev/null
+++ b/t/t4018/scheme-define-variant
@@ -0,0 +1,4 @@
+(define* (some-func x y z) RIGHT
+  (let ((a x)
+        (b y))
+        (ChangeMe a b)))

diff --git a/t/t4018/scheme-library b/t/t4018/scheme-library
new file mode 100644 (file)
index 0000000..82ea3df
--- /dev/null
+++ b/t/t4018/scheme-library
@@ -0,0 +1,11 @@
+(library (my-helpers id-stuff) RIGHT
+  (export find-dup)
+  (import (ChangeMe))
+  (define (find-dup l)
+    (and (pair? l)
+         (let loop ((rest (cdr l)))
+           (cond
+            [(null? rest) (find-dup (cdr l))]
+            [(bound-identifier=? (car l) (car rest))
+             (car rest)]
+            [else (loop (cdr rest))])))))

diff --git a/t/t4018/scheme-local-define b/t/t4018/scheme-local-define
new file mode 100644 (file)
index 0000000..bc6d8ae
--- /dev/null
+++ b/t/t4018/scheme-local-define
@@ -0,0 +1,4 @@
+(define (higher-order)
+  (define local-function RIGHT
+    (lambda (x)
+     (car "this is" "ChangeMe"))))

diff --git a/t/t4018/scheme-module b/t/t4018/scheme-module
new file mode 100644 (file)
index 0000000..edfae0e
--- /dev/null
+++ b/t/t4018/scheme-module
@@ -0,0 +1,6 @@
+(module A RIGHT
+  (export with-display-exception)
+  (extern (display-exception display-exception ChangeMe))
+  (def (with-display-exception thunk)
+    (with-catch (lambda (e) (display-exception e (current-error-port)) e)
+      thunk)))

diff --git a/t/t4018/scheme-top-level-define b/t/t4018/scheme-top-level-define
new file mode 100644 (file)
index 0000000..624743c
--- /dev/null
+++ b/t/t4018/scheme-top-level-define
@@ -0,0 +1,4 @@
+(define (some-func x y z) RIGHT
+  (let ((a x)
+        (b y))
+        (ChangeMe a b)))

diff --git a/t/t4018/scheme-user-defined-define b/t/t4018/scheme-user-defined-define
new file mode 100644 (file)
index 0000000..35fe7cc
--- /dev/null
+++ b/t/t4018/scheme-user-defined-define
@@ -0,0 +1,6 @@
+(define-test-suite record\ case-tests RIGHT
+  (record-case-1 (lambda (fail)
+                   (let ((a (make-foo 1 2)))
+                     (record-case a
+                       ((bar x) (ChangeMe))
+                       ((foo a b) (+ a b)))))))

diff --git a/t/t4034-diff-words.sh b/t/t4034-diff-words.sh
index 56f1e62a97bff51505956e672b023d4f681aaf1d..ee7721ab913584dce0276154852ccf64aa10c318 100755 (executable)
--- a/t/t4034-diff-words.sh
+++ b/t/t4034-diff-words.sh
@@ -325,6 +325,7 @@ test_language_driver perl
 test_language_driver php
 test_language_driver python
 test_language_driver ruby
+test_language_driver scheme
 test_language_driver tex
 
 test_expect_success 'word-diff with diff.sbe' '

diff --git a/t/t4034/scheme/expect b/t/t4034/scheme/expect
new file mode 100644 (file)
index 0000000..496cd5d
--- /dev/null
+++ b/t/t4034/scheme/expect
@@ -0,0 +1,11 @@
+<BOLD>diff --git a/pre b/post<RESET>
+<BOLD>index 74b6605..63b6ac4 100644<RESET>
+<BOLD>--- a/pre<RESET>
+<BOLD>+++ b/post<RESET>
+<CYAN>@@ -1,6 +1,6 @@<RESET>
+(define (<RED>myfunc a b<RESET><GREEN>my-func first second<RESET>)
+  ; This is a <RED>really<RESET><GREEN>(moderately)<RESET> cool function.
+  (<RED>this\place<RESET><GREEN>that\place<RESET> (+ 3 4))
+  (define <RED>some-text<RESET><GREEN>|a greeting|<RESET> "hello")
+  (let ((c (<RED>+ a b<RESET><GREEN>add1 first<RESET>)))
+    (format "one more than the total is %d" (<RED>add1<RESET><GREEN>+<RESET> c <GREEN>second<RESET>))))

diff --git a/t/t4034/scheme/post b/t/t4034/scheme/post
new file mode 100644 (file)
index 0000000..63b6ac4
--- /dev/null
+++ b/t/t4034/scheme/post
@@ -0,0 +1,6 @@
+(define (my-func first second)
+  ; This is a (moderately) cool function.
+  (that\place (+ 3 4))
+  (define |a greeting| "hello")
+  (let ((c (add1 first)))
+    (format "one more than the total is %d" (+ c second))))

diff --git a/t/t4034/scheme/pre b/t/t4034/scheme/pre
new file mode 100644 (file)
index 0000000..74b6605
--- /dev/null
+++ b/t/t4034/scheme/pre
@@ -0,0 +1,6 @@
+(define (myfunc a b)
+  ; This is a really cool function.
+  (this\place (+ 3 4))
+  (define some-text "hello")
+  (let ((c (+ a b)))
+    (format "one more than the total is %d" (add1 c))))

diff --git a/userdiff.c b/userdiff.c
index 3f81a2261c5e97e5cf50c1dc45ed196da8759f69..3897317aff892a22bd3d3cd6ba66b35203e9ef6d 100644 (file)
--- a/userdiff.c
+++ b/userdiff.c
@@ -191,6 +191,15 @@ PATTERNS("rust",
         "[a-zA-Z_][a-zA-Z0-9_]*"
         "|[0-9][0-9_a-fA-Fiosuxz]*(\\.([0-9]*[eE][+-]?)?[0-9_fF]*)?"
         "|[-+*\\/<>%&^|=!:]=|<<=?|>>=?|&&|\\|\\||->|=>|\\.{2}=|\\.{3}|::"),
+PATTERNS("scheme",
+        "^[\t ]*(\\(((define|def(struct|syntax|class|method|rules|record|proto|alias)?)[-*/ \t]|(library|module|struct|class)[*+ \t]).*)$",
+        /*
+         * R7RS valid identifiers include any sequence enclosed
+         * within vertical lines having no backslashes
+         */
+        "\\|([^\\\\]*)\\|"
+        /* All other words should be delimited by spaces or parentheses */
+        "|([^][)(}{[ \t])+"),
 PATTERNS("bibtex", "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
         "[={}\"]|[^={}\" \t]+"),
 PATTERNS("tex", "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",