<code>
filter not_too_far
-int var;
{
+ int var;
if defined( rip_metric ) then
var = rip_metric;
else {
<code>
function name ()
-int local_variable;
{
- local_variable = 5;
+ int local_variable;
+ int another_variable = 5;
}
function with_parameters (int parameter)
}
</code>
-<p>Unlike in C, variables are declared after the <cf/function/ line, but before
-the first <cf/{/. You can't declare variables in nested blocks. Functions are
-called like in C: <cf>name(); with_parameters(5);</cf>. Function may return
-values using the <cf>return <m/[expr]/</cf> command. Returning a value exits
-from current function (this is similar to C).
+<p>Like in C programming language, variables are declared inside function body,
+either at the beginning, or mixed with other statements. Declarations may
+contain initialization. You can also declare variables in nested blocks, such
+variables have scope restricted to such block. There is a deprecated syntax to
+declare variables after the <cf/function/ line, but before the first <cf/{/.
+Functions are called like in C: <cf>name(); with_parameters(5);</cf>. Function
+may return values using the <cf>return <m/[expr]/</cf> command. Returning a
+value exits from current function (this is similar to C).
-<p>Filters are defined in a way similar to functions except they can't have
+<p>Filters are defined in a way similar to functions except they cannot have
explicit parameters. They get a route table entry as an implicit parameter, it
is also passed automatically to any functions called. The filter must terminate
-with either <cf/accept/ or <cf/reject/ statement. If there's a runtime error in
+with either <cf/accept/ or <cf/reject/ statement. If there is a runtime error in
filter, the route is rejected.
<p>A nice trick to debug filters is to use <cf>show route filter <m/name/</cf>
#define f_generate_complex(fi_code, da, arg) \
f_new_inst(FI_EA_SET, f_new_inst(fi_code, f_new_inst(FI_EA_GET, da), arg), da)
+static int
+f_new_var(struct sym_scope *s)
+{
+ /*
+ * - A variable is an offset on vstack from vbase.
+ * - Vbase is set on filter start / function call.
+ * - Scopes contain anonymous scopes (blocks) inside filter/function scope
+ * - Each scope knows number of vars in that scope
+ * - Offset is therefore a sum of 'slots' up to named scope
+ * - New variables are added on top of vstk, so intermediate values cannot
+ * be there during FI_VAR_INIT. I.e. no 'var' inside 'term'.
+ * - Also, each f_line must always have its scope, otherwise a variable may
+ * be defined but not initialized if relevant f_line is not executed.
+ */
+
+ int offset = s->slots++;
+
+ while (!s->name)
+ {
+ s = s->next;
+ ASSERT(s);
+ offset += s->slots;
+ }
+
+ if (offset >= 0xff)
+ cf_error("Too many variables, at most 255 allowed");
+
+ return offset;
+}
+
/*
* Sets and their items are during parsing handled as lists, linked
* through left ptr. The first item in a list also contains a pointer
%nonassoc ELSE
%type <xp> cmds_int cmd_prep
-%type <x> term cmd cmds constant constructor print_list var_list function_call symbol_value bgp_path_expr bgp_path bgp_path_tail
+%type <x> term cmd cmd_var cmds cmds_scoped constant constructor print_list var var_init var_list function_call symbol_value bgp_path_expr bgp_path bgp_path_tail
%type <fda> dynamic_attr
%type <fsa> static_attr
%type <f> filter where_filter
function_vars:
/* EMPTY */ { $$ = 0; }
| function_vars type symbol ';' {
- cf_define_symbol($3, SYM_VARIABLE | $2, offset, sym_->scope->slots++);
+ cf_define_symbol($3, SYM_VARIABLE | $2, offset, f_new_var(sym_->scope));
$$ = $1 + 1;
}
;
| cmds_int { $$ = $1.begin; }
;
-cmd_prep: cmd {
+cmds_scoped: { cf_push_soft_scope(); } cmds { cf_pop_soft_scope(); $$ = $2; } ;
+
+cmd_var: var | cmd ;
+
+cmd_prep: cmd_var {
$$.begin = $$.end = $1;
if ($1)
while ($$.end->next)
;
switch_body: /* EMPTY */ { $$ = NULL; }
- | switch_body switch_items ':' cmds {
+ | switch_body switch_items ':' cmds_scoped {
/* Fill data fields */
struct f_tree *t;
struct f_line *line = f_linearize($4, 0);
t->data = line;
$$ = f_merge_items($1, $2);
}
- | switch_body ELSECOL cmds {
+ | switch_body ELSECOL cmds_scoped {
struct f_tree *t = f_new_tree();
t->from.type = t->to.type = T_VOID;
t->right = t;
}
;
+var_init:
+ /* empty */ { $$ = f_new_inst(FI_CONSTANT, (struct f_val) { }); }
+ | '=' term { $$ = $2; }
+ ;
+
+var:
+ type symbol var_init ';' {
+ struct symbol *sym = cf_define_symbol($2, SYM_VARIABLE | $1, offset, f_new_var(sym_->scope));
+ $$ = f_new_inst(FI_VAR_INIT, $3, sym);
+ }
+
cmd:
- '{' cmds '}' {
+ '{' cmds_scoped '}' {
$$ = $2;
}
| IF term THEN cmd {
| PRINTN print_list ';' {
$$ = f_new_inst(FI_PRINT, $2);
}
- | function_call ';' { $$ = f_new_inst(FI_DROP_RESULT, $1); }
+ | function_call ';' { $$ = f_new_inst(FI_DROP_RESULT, $1); }
| CASE term '{' switch_body '}' {
$$ = f_new_inst(FI_SWITCH, $2, build_tree($4));
}
RESULT(T_BOOL, i, ipa_is_ip4(v1.val.ip));
}
+ INST(FI_VAR_INIT, 1, 0) {
+ NEVER_CONSTANT;
+ ARG_ANY(1);
+ SYMBOL;
+ ARG_TYPE(1, sym->class & 0xff);
+
+ /* New variable is always the last on stack */
+ uint pos = curline.vbase + sym->offset;
+ fstk->vstk[pos] = v1;
+ fstk->vcnt = pos + 1;
+ }
+
/* Set to indirect value prepared in v1 */
INST(FI_VAR_SET, 1, 0) {
NEVER_CONSTANT;
*/
function t_bool()
-bool b;
{
- b = true;
+ bool b = true;
bt_assert(b);
bt_assert(!!b);
define '1a-a1' = (xyzzy-100);
function t_int()
-int i;
{
bt_assert(xyzzy = 130);
bt_assert('1a-a1' = 30);
- i = four;
+ int i = four;
i = 12*100 + 60/2 + i;
i = (i + 0);
bt_assert(i = 1234);
define is3 = [5, 17, 2, 11, 8, 15, 3, 19];
function t_int_set()
-int set is;
{
- is = [];
+ int set is = [];
bt_assert(is = []);
bt_assert(0 !~ is);
*/
function t_string()
-string st;
{
- st = "Hello";
+ string st = "Hello";
bt_assert(format(st) = "Hello");
bt_assert(st ~ "Hell*");
bt_assert(st ~ "?ello");
}
function t_pair()
-pair pp;
{
- pp = (1, 2);
+ pair pp = (1, 2);
bt_assert(format(pp) = "(1,2)");
bt_assert((1,2) = pp);
bt_assert((1,1+1) = pp);
*/
function t_pair_set()
-pair pp;
-pair set ps;
{
- pp = (1, 2);
- ps = [];
+ pair pp = (1, 2);
+ pair set ps = [];
bt_assert(pp !~ ps);
ps = [(1,(one+one)), (3,4)..(4,8), (5,*), (6,3..6)];
return 15;
}
+function local_vars(int j)
+{
+ int k = 10;
+ bt_assert(j = 5 && k = 10);
+ {
+ int j = 15;
+ k = 20;
+ bt_assert(j = 15 && k = 20);
+ }
+ bt_assert(j = 5 && k = 20);
+
+ if j < 10 then
+ {
+ int j = 25;
+ string k = "hello";
+ bt_assert(j = 25 && k = "hello");
+ }
+ bt_assert(j = 5 && k = 20);
+
+ int m = 100;
+ {
+ j = 35;
+ int k = 40;
+ bt_assert(j = 35 && k = 40 && m = 100);
+ }
+ bt_assert(j = 35 && k = 20 && m = 100);
+}
+
function factorial(int x)
{
if x = 0 then return 0;
}
function hanoi_solve(int n; bgppath h_src; bgppath h_dst; bgppath h_aux; bool x; bool y)
-bgppath tmp1;
-bgppath tmp2;
-int v;
{
# x -> return src or dst
# y -> print state
if n = 0 then { if x then return h_src; else return h_dst; }
- tmp1 = hanoi_solve(n - 1, h_src, h_aux, h_dst, true, y);
- tmp2 = hanoi_solve(n - 1, h_src, h_aux, h_dst, false, false);
+ bgppath tmp1 = hanoi_solve(n - 1, h_src, h_aux, h_dst, true, y);
+ bgppath tmp2 = hanoi_solve(n - 1, h_src, h_aux, h_dst, false, false);
h_src = tmp1;
h_aux = tmp2;
- v = h_src.first;
+ int v = h_src.first;
# bt_assert(h_dst = +empty+ || v < h_dst.first);
h_src = delete(h_src, v);
h_dst = prepend(h_dst, v);
bt_assert(callme(4, 4) = 16);
bt_assert(callme(7, 2) = 14);
bt_assert(callmeagain(1, 2, 3) = 6);
+ local_vars(5);
bt_assert(factorial(5) = 120);
bt_assert(factorial(10) = 3628800);
projects / thirdparty / bird.git / commitdiff
