tree grammar Simplifier; options { tokenVocab=Poly; ASTLabelType=CommonTree; output=AST; backtrack=true; // rewrite=true; // works either in rewrite or normal mode } /** Match some common patterns that we can reduce via identity * definitions. Since this is only run once, it will not be * perfect. We'd need to run the tree into this until nothing * changed to make it correct. */ poly: ^('+' a=INT b=INT) -> INT[String.valueOf($a.int+$b.int)] | ^('+' ^('+' a=INT p=poly) b=INT) -> ^('+' $p INT[String.valueOf($a.int+$b.int)]) | ^('+' ^('+' p=poly a=INT) b=INT) -> ^('+' $p INT[String.valueOf($a.int+$b.int)]) | ^('+' p=poly q=poly)-> {$p.tree.toStringTree().equals("0")}? $q -> {$q.tree.toStringTree().equals("0")}? $p -> ^('+' $p $q) | ^(MULT INT poly) -> {$INT.int==1}? poly -> ^(MULT INT poly) | ^('^' ID e=INT) -> {$e.int==1}? ID -> {$e.int==0}? INT["1"] -> ^('^' ID INT) | INT | ID ;