in reply to Re: Where does $4 come from here?
in thread Where does $4 come from here?

My understanding is that:

$1 $2 $3 supposed to refer to the 3 elements on the right of the production.

While $$ refer to the LHS of the production. But in this production, there're only 3 elements on the right hand side, and I don't see what $4 refers to...

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Re^3: Where does $4 come from here?
by Anonymous Monk on Jul 27, 2011 at 08:11 UTC

    But in this production, there're only 3 elements on the right hand side, and I don't see what $4 refers to...

    Ok, here is more guessing, if we're talking about GRAMPROG  remember stmtseq and 

    
remember: /* NULL */ /* start a full lexical scope */
{ $$ = block_start(TRUE); }
;

stmtseq : /* NULL */
{ $$ = (OP*)NULL; }
| stmtseq fullstmt
{ $$ = op_append_list(OP_LINESEQ, $1, $2);
PL_pad_reset_pending = TRUE;
if ($1 && $2)
PL_hints |= HINT_BLOCK_SCOPE;
}
;

    [download]
    then surely $$ = op_append_list(OP_LINESEQ, $1, $2); becomes $2, $3, $4, right?

    :)

[reply]
[d/l]
[select]

      No, that's not how yacc works AFAIK...

[reply]

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