Merge pull request #37 from introom/rule_argument

invoking rule with argument

Author: habnabit

ometa/interp.py

@@ -20,13 +20,13 @@ class TrampolinedGrammarInterpreter(object):
     An interpreter for OMeta grammars that processes input
     incrementally.
     """
-    def __init__(self, grammar, ruleName, callback=None, globals=None):
+    def __init__(self, grammar, rule, callback=None, globals=None):
         self.grammar = grammar
         self.position = 0
         self.callback = callback
         self.globals = globals or {}
         self.rules = decomposeGrammar(grammar)
-        self.next = self.apply(ruleName, None, ())
+        self.next = self.setNext(rule)
         self._localsStack = []
         self.currentResult = None
         self.input = InputStream([], 0)
@@ -68,6 +68,12 @@ def end(self):
             self.callback(*x)
 
 
+    def setNext(self, rule):
+        if not isinstance(rule, tuple):
+            rule = (rule, )
+        return self.apply(rule[0], None, rule[1:])
+
+
     ## Implementation note: each method, instead of being a function
     ## returning a value, is a generator that will yield '_feed_me' an
     ## arbitrary number of times, then finally yield the value of the
@@ -148,10 +154,15 @@ def apply(self, ruleName, codeName, args):
         Invoke a rule, optionally with arguments.
         """
         argvals = []
-        for a in args:
-            for x in self._eval(a):
-                if x is _feed_me: yield x
-            argvals.append(x[0])
+        # we tell whether a rule is a manually set one by the codeName
+        # if it's None, then we think it's set by setNext
+        if codeName is None:
+            argvals = args
+        else:
+            for a in args:
+                for x in self._eval(a):
+                    if x is _feed_me: yield x
+                argvals.append(x[0])
         _locals = {}
         self._localsStack.append(_locals)
         try:

ometa/test/test_tube.py

@@ -34,6 +34,7 @@ def setUp(self):
         _grammar =  r"""
             delimiter = '\r\n'
             initial = <(~delimiter anything)*>:val delimiter -> receiver.receive(val)
+            witharg :arg1 :arg2 = <(~delimiter anything)*>:a delimiter -> receiver.receive(arg1+arg2+a)
         """
         self.grammar = self._parseGrammar(_grammar)
 
@@ -75,3 +76,16 @@ def test_bindings(self):
         bindings = {'SMALL_INT': 3}
         TrampolinedParser(self._parseGrammar(grammar), receiver, bindings).receive('0')
         self.assertEqual(receiver.received, [3])
+
+
+    def test_currentRuleWithArgs(self):
+        """
+        TrampolinedParser should be able to invoke curruent rule with args.
+        """
+        receiver = TrampolinedReceiver()
+        receiver.currentRule = "witharg", "nice ", "day"
+        trampolinedParser = TrampolinedParser(self.grammar, receiver, {})
+        buf = b' oh yes\r\n'
+        for c in iterbytes(buf):
+            trampolinedParser.receive(c)
+        self.assertEqual(receiver.received, ["nice day oh yes"])

ometa/tube.py

@@ -26,7 +26,7 @@ def _setupInterp(self):
         'initial'.
         """
         self._interp = TrampolinedGrammarInterpreter(
-            grammar=self.grammar, ruleName=self.receiver.currentRule,
+            grammar=self.grammar, rule=self.receiver.currentRule,
             callback=None, globals=self.bindings)