Re^2: Left-associative binary operators in Parse::RecDescent

in reply to Re: Left-associative binary operators in Parse::RecDescent
in thread Left-associative binary operators in Parse::RecDescent

The good news: I applied your technique and it seems to work! The new grammar will parse everything the old one did and the new syntax too.

The bad news: it's incredibly slow! The test suite which used to run in a few seconds now takes so long that I have to kill it on the complex grammar test.

Here's the grammar I'm using now:

expression    : logical_expr /^\$/  { \$return = \$item[1]; } 

logical_expr : comparison_expr logical_op logical_expr 
               { [ \$item[2][0], \$item[2][1], \$item[1], \$item[3] ] 
+}
             | comparison_expr
               { \$item[1] }

comparison_expr : math_expr comparison_op comparison_expr 
                  { [ \$item[2][0], \$item[2][1], \$item[1], \$item[3]
+ ] }
                | math_expr
                  { \$item[1] }

math_expr       : paren_expr math_op math_expr 
                  { [ \$item[2][0], \$item[2][1], \$item[1], \$item[3]
+ ] }
                | paren_expr
                  { \$item[1] }

paren_expr : '(' logical_expr ')' { \$item[2] }
           | atom

logical_op    : /\\|\\||or|&&|and/   { [ ${\BIN_OP},  \$item[1] ] }

comparison_op : /le|ge|eq|ne|lt|gt/  { [ ${\BIN_OP},  \$item[1] ] }
              | />=?|<=?|!=|==/      { [ ${\BIN_OP},  \$item[1] ] }

math_op       : /[-+*\\/\%]/         { [ ${\BIN_OP},  \$item[1] ] }

atom          : function_call | var | literal

function_call : function_name '(' args ')'  
                { [ ${\FUNCTION_CALL}, \$item[1], \$item[3] ] }
              | function_name ...'(' logical_expr
                { [ ${\FUNCTION_CALL}, \$item[1], [ \$item[3] ] ] }
              | function_name '(' ')'
                { [ ${\FUNCTION_CALL}, \$item[1] ] }

function_name : /[A-Za-z_][A-Za-z0-9_]*/
                { \$item[1] }

args          : <leftop: logical_expr ',' logical_expr>

var           : /[A-Za-z_][A-Za-z0-9_]*/  { \\\$item[1] }

literal       : /-?\\d*\\.\\d+/           { \$item[1] }
              | /-?\\d+/                  { \$item[1] }
              | <perl_quotelike>          { \$item[1][2] }
[download]

Any ideas what might be going wrong?

-sam

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