On 14 Aug 2005, at 21:43, Roberto Mandall wrote:
thx for the answer,but i still get errors, i guess i just do not
undertsnad bison well enough.
i have this now:
%nonassoc ELSE
%nonassoc THEN
open_if_statement : IF boolean_expression {} THEN statement {/}
|IF boolean_expression {} THEN closed_statement ELSE
open_statement{} ;
closed_if_statement : IF boolean_expression {} THEN
closed_statement ELSE closed_statement {};
i get this:
bison -d --debug -v parser.y
parser.y: conflicts: 1 reduce/reduce
parser out put says:
State 140 conflicts: 1 reduce/reduce
state 140 has got this:
state 140
38 statement: closed_statement .
54 open_if_statement: IF boolean_expression THEN
closed_statement . @13 ELSE open_statement
56 closed_if_statement: IF boolean_expression THEN
closed_statement . @14 ELSE closed_statement
ELSE reduce using rule 53 (@13)
ELSE [reduce using rule 55 (@14)]
$default reduce using rule 38 (statement)
@13 go to state 162
@14 go to state 163
can any1 plz tell me what am i doing wrong? i do really need those
semantic rules after the "THEN closed_statement"
You have put a series of mid-rule actions, which causes reduce/reduce
conflicts, as implemented as an empty rule. The token precedences
just looks at the tokens immediately before and after the ".", and
cannot resolve that. So you have to remove those mid-rule actions,
putting the actions in the rules of the grammar variables preceding
them.
Hans Aberg
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