Target code lines

If a target predicate consists of one line of C, there is a special syntactic alternative for it. Target code lines consist of arbitrary C text, terminated by a newline character. If necessary, the newline also simulates a ','-token to the parser, so no intermediate commas are necessary with target code lines.

Target predicates may be used for test and set of node attributes or debugging generated code. E.g. the following rule tests whether a node is marked as deleted and removes it from some graphs:

  
GRS DeleteFromStatementLists(Proc:ProcGlobal)
{
   RULES
      Body(Proc,PBody),
      {* /* This target code is printed after the code for  */
         /* the preceeding predicate Body                   */ *},
      LinearBlocks(PBody,Block),
      * /* and this here is a single line of target code */
      Stmts(Block,Ass),
      Ass ~ Assign,
      {* /* target predicate to test, whether a node was really deleted */
         /* is copied to the rule test after the pattern match on Assign */
         if (!SimpleSTMT_Assign_get_deleted(Ass))
            continue;
      *}
   ==>
      DELETE Ass FREE;,       // really deallocate Ass
      * printf("deleting copy statement %s",STMT_provide_label(Ass)); 
      NOT Stmts(Block,Ass), 
      NOT list_of_definitions(Proc,Ass)
      * /* This here is really the end of the rule */
   ;
}