This is a pretty good idea, but I'm not sure if it's possible. For
instance in the case of an if statement I modified my grammar as such:
if_statement:
t_IF t_LPAREN expression t_RPAREN {yyexpect_statement;} statement
t_ELSE statement
<...>
| t_IF t_LPAREN expression t_RPAREN {yyexpect_statement;} statement
%prec p_IF
<...>
;
Where yyexpect_statement is a macro I defined to set a global flag and
then the lexer checks and returns an appropriate t_LCURLY for
statements. The problem I'm seeing here is that the glr parser defers
my mid-action rule so the lexer can't adjust in time.
On Nov 11, 2008, at 11:08 AM, Hans Aberg wrote:
On 11 Nov 2008, at 08:10, Marcel Laverdet wrote:
It's unclear here whether the child of the if statement should be
an empty Block or an empty ObjectLiteral. The ECMAScript spec
addresses this simply:
"Note that an ExpressionStatement cannot start with an opening
curly brace because that might make it ambiguous with a Block."
You might try defining two pairs of braces, one for the blocks, an
one for the statements. This should disambiguate the grammar. Then
set a context switch that tells the lexer which type to return; the
switch is changed from the parser.
Hans
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