Add <?> (null) and <!> (fail) assertions.

perl6 · Oct 14, 2009 · a3bc5aa · a3bc5aa
1 parent 9ca78a9
commit a3bc5aa
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Showing 2 changed files with 16 additions and 6 deletions.
diff --git a/src/Regex/P6Regex/Actions.pm b/src/Regex/P6Regex/Actions.pm
@@ -256,15 +256,25 @@ method backslash:sym<misc>($/) {
 
 
 method assertion:sym<?>($/) {
-    my $past := $<assertion>.ast;
-    $past.subtype('zerowidth');
+    my $past;
+    if $<assertion> {
+        $past := $<assertion>.ast;
+        $past.subtype('zerowidth');
+    }
+    else { $past := 0; }
     make $past;
 }
 
 method assertion:sym<!>($/) {
-    my $past := $<assertion>.ast;
-    $past.negate( !$past.negate );
-    $past.subtype('zerowidth');
+    my $past;
+    if $<assertion> {
+        $past := $<assertion>.ast;
+        $past.negate( !$past.negate );
+        $past.subtype('zerowidth');
+    }
+    else { 
+        $past := PAST::Regex.new( :pasttype('anchor'), :subtype('fail') );
+    }
     make $past;
 }
 

diff --git a/t/p6regex/rx_lookarounds b/t/p6regex/rx_lookarounds
@@ -37,7 +37,7 @@ x | y | <?>	\t\n\r !"#$%&'()*+,-./:;<=>?@[\]^`_{|}0123456789ABCDEFGHIJabcdefghij
 
 abc <!> def	\t\n\r !"#$%&'()*+,-./:;<=>?@[\]^`_{|}0123456789ABCDEFGHIJabcdefghij	n	fail pattern <!>
 
-a[b}		\t\n\r !"#$%&'()*+,-./:;<=>?@[\]^`_{|}0123456789ABCDEFGHIJabcdefghij	/rule error/	mismatched close
+a[b}		\t\n\r !"#$%&'()*+,-./:;<=>?@[\]^`_{|}0123456789ABCDEFGHIJabcdefghij	/error/	mismatched close
 
 c <before .d>		abacad		/mob: <c @ 3>/				one character and lookahead <before>
 .* <before .d>		abacad		/mob: <abac @ 0>/			multiple characters and lookahead <before>