[866] in java-interest
More syntactic ambiguity
daemon@ATHENA.MIT.EDU (Scott Hudson)
Sat Aug 12 01:17:01 1995
From: "Scott Hudson" <hudson@cs.arizona.edu>
To: java-interest@java.sun.com
Date: Fri, 11 Aug 1995 16:39:47 -0700 (MST)
*** This is a repost due to apparent network failure.
*** Apologies if you get this twice.
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The language spec grammar contains the productions:
variableinitializer =
expression
| '{' (variableinitializer ( ',' variableinitializer )* ','? )? '}'
Under this grammar, the construct: "{a,b}" is ambiguous since "a,b" could
be a single expression (using the comma operator) or a list of
variableinitializers.
The same ambiguity occurs in:
arglist = expression (',' expression )*
This is normally handled by not allowing a full expression in these
contexts, but instead using the expression construct for the operator
with the next higher precedence than the comma operator within the
precedence separated productions (assignment_expr in the ANSI C
grammar). Unfortunately, this grammar has no such production. This
probably needs to be fixed.
Scott
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