String#match? and Symbol#match?

* string.c (rb_str_match_m_p): inverse of Regexp#match?.  based on
  the patch by Herwin Weststrate <herwin@snt.utwente.nl>.
  [Fix GH-1483] [Feature #12898]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57053 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

internal.h

@@ -1394,6 +1394,7 @@ VALUE rb_rational_cmp(VALUE self, VALUE other);
 VALUE rb_reg_compile(VALUE str, int options, const char *sourcefile, int sourceline);
 VALUE rb_reg_check_preprocess(VALUE);
 long rb_reg_search0(VALUE, VALUE, long, int, int);
+VALUE rb_reg_match_p(VALUE re, VALUE str, long pos);
 void rb_backref_set_string(VALUE string, long pos, long len);
 int rb_match_count(VALUE match);
 int rb_match_nth_defined(int nth, VALUE match);

re.c

@@ -3225,19 +3225,22 @@ rb_reg_match_m(int argc, VALUE *argv, VALUE re)
 static VALUE
 rb_reg_match_m_p(int argc, VALUE *argv, VALUE re)
 {
-    VALUE str, initpos;
+    long pos = rb_check_arity(argc, 1, 2) > 1 ? NUM2LONG(argv[1]) : 0;
-    long pos = 0;
+    return rb_reg_match_p(re, argv[0], pos);
+}
+
+VALUE
+rb_reg_match_p(VALUE re, VALUE str, long pos)
+{
     regex_t *reg;
     onig_errmsg_buffer err = "";
     OnigPosition result;
     const UChar *start, *end;
     int tmpreg;
 
-    rb_scan_args(argc, argv, "11", &str, &initpos);
     if (NIL_P(str)) return Qfalse;
-    str = SYMBOL_P(str) ? rb_sym2str(str) : rb_str_to_str(str);
+    str = SYMBOL_P(str) ? rb_sym2str(str) : StringValue(str);
-    if (argc == 2) {
+    if (pos) {
-	pos = NUM2LONG(initpos);
 	if (pos < 0) {
 	    pos += NUM2LONG(rb_str_length(str));
 	    if (pos < 0) return Qfalse;

string.c

@@ -3601,6 +3601,32 @@ rb_str_match_m(int argc, VALUE *argv, VALUE str)
     return result;
 }
 
+/*
+ *  call-seq:
+ *     str.match?(pattern)        -> true or false
+ *     str.match?(pattern, pos)   -> true or false
+ *
+ *  Converts _pattern_ to a +Regexp+ (if it isn't already one), then
+ *  returns a +true+ or +false+ indicates whether the regexp is
+ *  matched _str_ or not without updating <code>$~</code> and other
+ *  related variables.  If the second parameter is present, it
+ *  specifies the position in the string to begin the search.
+ *
+ *     "Ruby".match?(/R.../)    #=> true
+ *     "Ruby".match?(/R.../, 1) #=> false
+ *     "Ruby".match?(/P.../)    #=> false
+ *     $&                       #=> nil
+ */
+
+static VALUE
+rb_str_match_m_p(int argc, VALUE *argv, VALUE str)
+{
+    VALUE re;
+    rb_check_arity(argc, 1, 2);
+    re = get_pat(argv[0]);
+    return rb_reg_match_p(re, str, argc > 1 ? NUM2LONG(argv[1]) : 0);
+}
+
 enum neighbor_char {
     NEIGHBOR_NOT_CHAR,
     NEIGHBOR_FOUND,
@@ -9738,6 +9764,19 @@ sym_match_m(int argc, VALUE *argv, VALUE sym)
     return rb_str_match_m(argc, argv, rb_sym2str(sym));
 }
 
+/*
+ * call-seq:
+ *   sym.match?(obj)   -> true or false
+ *
+ * Returns <code>sym.to_s.match?(obj)</code>.
+ */
+
+static VALUE
+sym_match_m_p(int argc, VALUE *argv, VALUE sym)
+{
+    return rb_str_match_m_p(argc, argv, sym);
+}
+
 /*
  * call-seq:
  *   sym[idx]      -> char
@@ -9924,6 +9963,7 @@ Init_String(void)
     rb_define_method(rb_cString, "empty?", rb_str_empty, 0);
     rb_define_method(rb_cString, "=~", rb_str_match, 1);
     rb_define_method(rb_cString, "match", rb_str_match_m, -1);
+    rb_define_method(rb_cString, "match?", rb_str_match_m_p, -1);
     rb_define_method(rb_cString, "succ", rb_str_succ, 0);
     rb_define_method(rb_cString, "succ!", rb_str_succ_bang, 0);
     rb_define_method(rb_cString, "next", rb_str_succ, 0);
@@ -10070,6 +10110,7 @@ Init_String(void)
     rb_define_method(rb_cSymbol, "size", sym_length, 0);
     rb_define_method(rb_cSymbol, "empty?", sym_empty, 0);
     rb_define_method(rb_cSymbol, "match", sym_match_m, -1);
+    rb_define_method(rb_cSymbol, "match?", sym_match_m_p, -1);
 
     rb_define_method(rb_cSymbol, "upcase", sym_upcase, -1);
     rb_define_method(rb_cSymbol, "downcase", sym_downcase, -1);

test/ruby/test_string.rb

@@ -2111,6 +2111,50 @@ CODE
     assert_raise(ArgumentError) { "foo".match }
   end
 
+  def test_match_p_regexp
+    /backref/ =~ 'backref'
+    # must match here, but not in a separate method, e.g., assert_send,
+    # to check if $~ is affected or not.
+    assert_equal(true, "".match?(//))
+    assert_equal(true, :abc.match?(/.../))
+    assert_equal(true, 'abc'.match?(/b/))
+    assert_equal(true, 'abc'.match?(/b/, 1))
+    assert_equal(true, 'abc'.match?(/../, 1))
+    assert_equal(true, 'abc'.match?(/../, -2))
+    assert_equal(false, 'abc'.match?(/../, -4))
+    assert_equal(false, 'abc'.match?(/../, 4))
+    assert_equal(true, "\u3042xx".match?(/../, 1))
+    assert_equal(false, "\u3042x".match?(/../, 1))
+    assert_equal(true, ''.match?(/\z/))
+    assert_equal(true, 'abc'.match?(/\z/))
+    assert_equal(true, 'Ruby'.match?(/R.../))
+    assert_equal(false, 'Ruby'.match?(/R.../, 1))
+    assert_equal(false, 'Ruby'.match?(/P.../))
+    assert_equal('backref', $&)
+  end
+
+  def test_match_p_string
+    /backref/ =~ 'backref'
+    # must match here, but not in a separate method, e.g., assert_send,
+    # to check if $~ is affected or not.
+    assert_equal(true, "".match?(''))
+    assert_equal(true, :abc.match?('...'))
+    assert_equal(true, 'abc'.match?('b'))
+    assert_equal(true, 'abc'.match?('b', 1))
+    assert_equal(true, 'abc'.match?('..', 1))
+    assert_equal(true, 'abc'.match?('..', -2))
+    assert_equal(false, 'abc'.match?('..', -4))
+    assert_equal(false, 'abc'.match?('..', 4))
+    assert_equal(true, "\u3042xx".match?('..', 1))
+    assert_equal(false, "\u3042x".match?('..', 1))
+    assert_equal(true, ''.match?('\z'))
+    assert_equal(true, 'abc'.match?('\z'))
+    assert_equal(true, 'Ruby'.match?('R...'))
+    assert_equal(false, 'Ruby'.match?('R...', 1))
+    assert_equal(false, 'Ruby'.match?('P...'))
+    assert_equal('backref', $&)
+  end
+
   def test_clear
     s = "foo" * 100
     s.clear