I am not sure whether following case is a gcc bug or not :
typedef int foo;
foo foo_fct(int a) {
foo foo; /* line 3: a variable foo with type foo
*/
return (foo)foo; /* line 4: gcc reports syntax error */
}
If gcc could , somehow, figure out the line 3 is a variable declaration,
maybe it should be able to handle line 4 , which is a cast expression.
Regards,
Mike
----- Original Message -----
From: "Ian Lance Taylor" <iant@xxxxxxxxxx>
To: "Michael Gong" <mwgong@xxxxxxxxxxxxxx>
Cc: <gcc-help@xxxxxxxxxxx>
Sent: Tuesday, January 23, 2007 10:28 AM
Subject: Re: typedef name question
"Michael Gong" <mwgong@xxxxxxxxxxxxxx> writes:
To clarify myself a bit, is my following understanding correct ?
For this case:
int main() {
int foo;
foo abc;
}
The Gcc's grammar does parse it, ie. an "identifier" can follow
another "identifier".
Then in the semantic analysis, gcc checks to make sure the first
identifier "foo" must represent a type. In this case, it is not. So
an
error is reported.
I think you may be applying compiler theory to a real world compiler.
A better way to describe what happens would be to say that the lexer
looks up each identifier in the symbol table to see whether it is a
type before the parser proper ever sees it.
A truer way to describe what happens would be to observe that gcc uses
a recursive descent parser, not a grammar.
Ian
