Changeset 10248 for src/Pugs/Lexer.hs

Timestamp:

05/09/06 17:53:22 (3 years ago)

Author:

audreyt

svk:copy_cache_prev:

13387

Message:

* Pugs.Lexer: ruleWs -- proper dynamic <ws> support for

cases where we can't infer what <ws> means statically
from rules input.

Files:

• src/Pugs/Lexer.hs (modified) (2 diffs)

src/Pugs/Lexer.hs

@@ -21 +21 @@
     rule, verbatimRule, literalRule,
     tryRule, tryVerbatimRule,
-    tryChoice, ruleComma,
+    tryChoice, ruleComma, ruleWs,
 
     ruleScope, ruleTrait, ruleTraitName, ruleBareTrait, ruleType,
@@ -131 +131 @@
     return contents
 
+-- The <ws> rule.
+ruleWs :: RuleParser ()
+ruleWs = do
+    prev <- getPrevCharClass
+    case prev of
+        SpaceClass -> whiteSpace
+        _  -> do
+            curr <- getCurrCharClass
+            if prev == curr then mandatoryWhiteSpace else case curr of
+                SpaceClass  -> whiteSpace
+                _           -> return ()
+
 {-|
 Match one or more identifiers, separated internally by the given delimiter.