lib/re: support regex subexpressions

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/standard/re.nit b/lib/standard/re.nit
index d68451e..20ea6b8 100644 (file)
--- a/lib/standard/re.nit
+++ b/lib/standard/re.nit
@@ -74,7 +74,7 @@ private extern class NativeRegex `{ regex_t* `}
                return message;
        `}
 
-       # The number of parenthetical subexpressions in this compiled regular expression
+       # Number of parenthetical subexpressions in this compiled regular expression
        fun re_nsub: Int `{ return recv->re_nsub; `}
 end
 
@@ -180,7 +180,7 @@ class Regex
        private var native: nullable NativeRegex = null
 
        # Cache of a single `regmatch_t` to prevent many calls to `malloc`
-       private var native_match = new NativeMatchArray.malloc(1) is lazy
+       private var native_match = new NativeMatchArray.malloc(native.re_nsub+1) is lazy
 
        # `cflags` of the last successful `compile`
        private var cflags_cache = 0
@@ -348,12 +348,26 @@ class Regex
                text = text.to_s
                var cstr = text.substring_from(from).to_cstring
                var eflags = gather_eflags
-               var match = self.native_match
+               var native_match = self.native_match
 
-               var res = native.regexec(cstr, 1, match, eflags)
+               var nsub = native.re_nsub
+               var res = native.regexec(cstr, nsub+1, native_match, eflags)
 
                # Found one?
-               if res == 0 then return new Match(text, from + match.rm_so, match.rm_eo - match.rm_so)
+               if res == 0 then
+                       var match = new Match(text,
+                               from + native_match.rm_so,
+                               native_match.rm_eo - native_match.rm_so)
+
+                       # Add sub expressions
+                       for i in [1..nsub] do
+                               match.subs.add new Match( text,
+                                       native_match[i].rm_so,
+                                       native_match[i].rm_eo - native_match[i].rm_so)
+                       end
+
+                       return match
+               end
 
                # No more match?
                if res.is_nomatch then return null
@@ -380,18 +394,30 @@ class Regex
                var cstr = text.to_cstring
                var eflags = gather_eflags
                var eflags_or_notbol = eflags.bin_or(flag_notbol)
-               var match = self.native_match
+               var native_match = self.native_match
                var matches = new Array[Match]
 
-               var res = native.regexec(cstr, 1, match, eflags)
+               var nsub = native.re_nsub
+               var res = native.regexec(cstr, nsub+1, native_match, eflags)
                var d = 0
                while res == 0 do
-                       matches.add new Match(text, d + match.rm_so, match.rm_eo - match.rm_so)
-                       if d == match.rm_eo then
+                       var match = new Match(text,
+                               d + native_match.rm_so,
+                               native_match.rm_eo - native_match.rm_so)
+                       matches.add match
+
+                       # Add sub expressions
+                       for i in [1..nsub] do
+                               match.subs.add new Match( text,
+                                       d + native_match[i].rm_so,
+                                       native_match[i].rm_eo - native_match[i].rm_so)
+                       end
+
+                       if d == native_match.rm_eo then
                                d += 1
-                       else d = d + match.rm_eo
-                       cstr = cstr.substring_from(match.rm_eo)
-                       res = native.regexec(cstr, 1, match, eflags_or_notbol)
+                       else d = d + native_match.rm_eo
+                       cstr = cstr.substring_from(native_match.rm_eo)
+                       res = native.regexec(cstr, nsub+1, native_match, eflags_or_notbol)
                end
 
                # No more match?
@@ -405,3 +431,15 @@ class Regex
 
        redef fun to_s do return "/{string}/"
 end
+
+redef class Match
+       # Parenthesized subexpressions in this match
+       #
+       # ~~~
+       # var re = "c (d e+) f".to_re
+       # var match = "a b c d eee f g".search(re)
+       # assert match.subs.length == 1
+       # assert match.subs.first.to_s == "d eee"
+       # ~~~
+       var subs = new Array[Match] is lazy
+end