Re: Forcing multiple parse stacks to 'reduce'

[Derek M Jones]

Hans,

>>In the case:
>>
>>typedef x, y;
>>typedef i, j;

I should have given the example as:

typedef x y;
typedef i j;

>>
>>the second typedef token is shifted onto all three stacks and
>>subsequent tokens are processed like a declaration (which they
>>do form part of)!  So I don't get a parse of a single declaration
>>(in fact yyparse eventually reports an ambiguity).

Mystery solved (while cutting down the grammar to provide a
minimum example).

The syntax for function definition (clause 6.9.1) is

function-definition:
declaration-specifiers declarator declaration-list-opt compound-statement

I have changed this to:

function-definition:
declaration-specifiers declarator declaration-list-opt  OPEN_CURL

I suddenly realised that the token sequence:

typedef x y;
typedef i j;
{

is a syntactically valid function definition.

Bison is correct not to perform the reductions I was
expecting.  Until a {, or EOF, is seen it does not it does not
know whether it is dealing with a function definition or a
list of declarations.


derek

--
Derek M Jones                                           tel: +44 (0) 1252 520 
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Knowledge Software Ltd                            mailto:address@hidden
Applications Standards Conformance Testing   http://www.knosof.co.uk