Merge: example: add 24 game task of Rosetta code

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

diff --git a/lib/standard/re.nit b/lib/standard/re.nit
index 20ea6b8..24637cb 100644 (file)
--- a/lib/standard/re.nit
+++ b/lib/standard/re.nit
@@ -42,7 +42,7 @@ private extern class NativeRegex `{ regex_t* `}
 
        # Compile the regular expression `regex` into a form that is suitable for subsequent `regexec` searches
        fun regcomp(regex: NativeString, cflags: Int): Int `{
-               return regcomp(recv, regex, cflags);
+               return regcomp(self, regex, cflags);
        `}
 
        # Match `string` against the precompiled pattern buffer of `self`, locating matches
@@ -50,32 +50,32 @@ private extern class NativeRegex `{ regex_t* `}
        # `nmatch` and `pmatch` are used to provide information regarding the location of any matches.
        # `eflags` may be the bitwise-or of one or both of `flag_notbol` and `flag_noteol`.
        fun regexec(string: NativeString, nmatch: Int, pmatch: NativeMatchArray, eflags: Int): Int `{
-               return regexec(recv, string, nmatch, pmatch, eflags);
+               return regexec(self, string, nmatch, pmatch, eflags);
        `}
 
        # Match `string` against the precompiled pattern buffer of `self`, do not locate matches
        #
        # `eflags` may be the bitwise-or of one or both of `flag_notbol` and `flag_noteol`.
        fun regexec_match_only(string: NativeString, eflags: Int): Int `{
-               return regexec(recv, string, 0, NULL, eflags);
+               return regexec(self, string, 0, NULL, eflags);
        `}
 
        # Free the memory allocated to the pattern buffer by the compiling process
        #
        # Does not free the memory holding `self`, use `free` for this purpose.
-       fun regfree `{ regfree(recv); `}
+       fun regfree `{ regfree(self); `}
 
        # Turn the error codes that can be returned by both `regcomp` and `regexec` into error message strings
        fun regerror(errcode: Int): NativeString `{
-               size_t len = regerror(errcode, recv, NULL, 0);
+               size_t len = regerror(errcode, self, NULL, 0);
                char *message = malloc(len);
-               regerror(errcode, recv, message, len);
+               regerror(errcode, self, message, len);
 
                return message;
        `}
 
        # Number of parenthetical subexpressions in this compiled regular expression
-       fun re_nsub: Int `{ return recv->re_nsub; `}
+       fun re_nsub: Int `{ return self->re_nsub; `}
 end
 
 # Flags for `NativeRegex::regcomp`
@@ -96,7 +96,7 @@ private fun error_nomatch: Int `{ return REG_NOMATCH; `}
 private fun error_espace: Int `{ return REG_ESPACE; `}
 
 redef universal Int
-       private fun is_nomatch: Bool `{ return recv == REG_NOMATCH; `}
+       private fun is_nomatch: Bool `{ return self == REG_NOMATCH; `}
 end
 
 # An array of `regmatch_t` or a pointer to one
@@ -105,17 +105,17 @@ private extern class NativeMatchArray `{ regmatch_t* `}
        new malloc(length: Int) `{ return malloc(length * sizeof(regmatch_t)); `}
 
        # The offset in string of the beginning of a substring
-       fun rm_so: Int `{ return recv->rm_so; `}
+       fun rm_so: Int `{ return self->rm_so; `}
 
        # The offset in string of the end of the substring
-       fun rm_eo: Int `{ return recv->rm_eo; `}
+       fun rm_eo: Int `{ return self->rm_eo; `}
 
        # Get a pointer to the element at `index`, can also be used as a subarray
-       fun [](index: Int): NativeMatchArray `{ return recv + index; `}
+       fun [](index: Int): NativeMatchArray `{ return self + index; `}
 end
 
 redef extern class NativeString
-       private fun substring_from(index: Int): NativeString `{ return recv + index; `}
+       private fun substring_from(index: Int): NativeString `{ return self + index; `}
 end
 
 redef class Text
@@ -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