lib/re: intro `Match::[]`

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

diff --git a/lib/standard/re.nit b/lib/standard/re.nit
index 20ea6b8..48142fe 100644 (file)
--- a/lib/standard/re.nit
+++ b/lib/standard/re.nit
@@ -442,4 +442,23 @@ 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