Changeset 207 for branches/interpreter2/UParser.pas

Timestamp:

Apr 20, 2020, 11:31:59 PM (5 years ago)

Author:

chronos

Message:

• Added: Optimizer class for implementation of various optimizations on AST.
• Added: Transformation of repeat-until loop to while-do loop.

File:

• branches/interpreter2/UParser.pas (modified) (4 diffs)

branches/interpreter2/UParser.pas

@@ -34 +34 @@
     function ParseRepeatUntil(Block: TBlock; out RepeatUntil: TRepeatUntil): Boolean;
     function ParseForToDo(Block: TBlock; out ForToDo: TForToDo): Boolean;
+    function ParseBreak(Block: TBlock; out BreakCmd: TBreak): Boolean;
+    function ParseContinue(Block: TBlock; out ContinueCmd: TContinue): Boolean;
     procedure TokenizerError(Pos: TPoint; Text: string);
     procedure InitSystemBlock(Block: TBlock);
@@ -121 +123 @@
   ForToDo: TForToDo;
   RepeatUntil: TRepeatUntil;
+  BreakCmd: TBreak;
+  ContinueCmd: TContinue;
 begin
   if ParseIfThenElse(Block, IfThenElse) then begin
@@ -149 +153 @@
     Result := True;
     Command := Assignment;
-  end else Result := False;
+  end else
+  if ParseBreak(Block, BreakCmd) then begin
+    Result := True;
+    Command := BreakCmd;
+  end else
+  if ParseContinue(Block, ContinueCmd) then begin
+    Result := True;
+    Command := ContinueCmd;
+  end else
+    Result := False;
 end;
 
@@ -563 +576 @@
 end;
 
+function TParser.ParseBreak(Block: TBlock; out BreakCmd: TBreak): Boolean;
+begin
+  Result := False;
+  if Tokenizer.CheckNext('break', tkKeyword) then begin
+    Tokenizer.Expect('break', tkKeyword);
+    Result := True;
+    BreakCmd := TBreak.Create;
+  end;
+end;
+
+function TParser.ParseContinue(Block: TBlock; out ContinueCmd: TContinue
+  ): Boolean;
+begin
+  Result := False;
+  if Tokenizer.CheckNext('continue', tkKeyword) then begin
+    Tokenizer.Expect('continue', tkKeyword);
+    Result := True;
+    ContinueCmd := TContinue.Create;
+  end;
+end;
+
 procedure TParser.TokenizerError(Pos: TPoint; Text: string);
 begin