Undo functionalities

The following builtin functions provides a mechanism to implement the UNDO & REDO functionalities.

  $\blacktriangleright$ Undo:Save(AST,SAVESYMTAB,SAVEDECL)

 
This function saves a AST in the UNDO list

• AST (input AST) is the AST to saved. It must be in the current unit (i.e. see $cunit) and must contains the modified AST.
• SAVESYMTAB (input BOOLEAN) indicates that the symbol table must be save (not yet implemented)
• SAVEDECL (input BOOLEAN) indicates that the declaration AST must be saved (not yet implemented)

$\vartriangleright$ Example 59:Save the AST before a transformation

  SCRIPT transfWithUndo()
    stat:=$cstat 
    foo:=Undo:Save(stat.PARENT,TRUE,TRUE) 
    stat <- PARSESTAT("        print *,100") 
  ENDSCRIPT