Merge: Misc AST

[nit.git] / lib / standard / re.nit

diff --git a/lib/standard/re.nit b/lib/standard/re.nit
index 20ea6b8..a58aba0 100644 (file)
--- a/lib/standard/re.nit
+++ b/lib/standard/re.nit
@@ -180,7 +180,12 @@ 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(native.re_nsub+1) is lazy
+       private var native_match: NativeMatchArray is lazy do
+               native_match_is_init = true
+               return new NativeMatchArray.malloc(native.re_nsub+1)
+       end
+
+       private var native_match_is_init = false
 
        # `cflags` of the last successful `compile`
        private var cflags_cache = 0
@@ -249,7 +254,10 @@ class Regex
                        native.regfree
                        native.free
                        self.native = null
-                       self.native_match.free
+
+                       if native_match_is_init then
+                               self.native_match.free
+                       end
                end
        end
 
@@ -442,4 +450,23 @@ redef class Match
        # assert match.subs.first.to_s == "d eee"
        # ~~~
        var subs = new Array[Match] is lazy
+
+       # Get the `n`th expression in this match
+       #
+       # `n == 0` returns this match, and a greater `n` returns the corresponding
+       # subexpression.
+       #
+       # Require: `n >= 0 and n <= subs.length`
+       #
+       # ~~~
+       # var re = "c (d e+) f".to_re
+       # var match = "a b c d eee f g".search(re)
+       # assert match[0].to_s == "c d eee f"
+       # assert match[1].to_s == "d eee"
+       # ~~~
+       fun [](n: Int): Match do
+               if n == 0 then return self
+               assert n > 0 and n <= subs.length
+               return subs[n-1]
+       end
 end