Changeset 201 for branches/interpreter2/UParser.pas

Timestamp:

Apr 16, 2020, 7:40:38 PM (5 years ago)

Author:

chronos

Message:

• Fixed: Memory leaks.

Location:

branches/interpreter2

Files:

• . (modified) (1 prop)
• UParser.pas (modified) (17 diffs)

branches/interpreter2/UParser.pas

@@ -16 +16 @@
     FOnError: TErrorEvent;
     Tokenizer: TTokenizer;
-    function ParseBeginEnd(Block: TBlock; var BeginEnd: TBeginEnd): Boolean;
-    function ParseFunctionCall(Block: TBlock; var FunctionCall: TFunctionCall): Boolean;
-    function ParseCommand(Block: TBlock; var Command: TCommand): Boolean;
-    function ParseProgram(SystemBlock: TBlock; var Prog: TProgram): Boolean;
-    function ParseBlock(ParentBlock: TBlock; var Block: TBlock): Boolean;
-    function ParseAssignment(Block: TBlock; var Assignment: TAssignment): Boolean;
-    function ParseExpression(Block: TBlock; var Expression: TExpression): Boolean;
-    function ParseIfThenElse(Block: TBlock; var IfThenElse: TIfThenElse): Boolean;
-    function ParseWhileDo(Block: TBlock; var WhileDo: TWhileDo): Boolean;
+    function ParseBeginEnd(Block: TBlock; out BeginEnd: TBeginEnd): Boolean;
+    function ParseFunctionCall(Block: TBlock; out FunctionCall: TFunctionCall): Boolean;
+    function ParseCommand(Block: TBlock; out Command: TCommand): Boolean;
+    function ParseProgram(SystemBlock: TBlock; out Prog: TProgram): Boolean;
+    function ParseBlock(ParentBlock: TBlock; out Block: TBlock): Boolean;
+    function ParseVarBlock(Block: TBlock): Boolean;
+    function ParseConstBlock(Block: TBlock): Boolean;
+    function ParseAssignment(Block: TBlock; out Assignment: TAssignment): Boolean;
+    function ParseExpression(Block: TBlock; out Expression: TExpression): Boolean;
+    function ParseIfThenElse(Block: TBlock; out IfThenElse: TIfThenElse): Boolean;
+    function ParseWhileDo(Block: TBlock; out WhileDo: TWhileDo): Boolean;
     procedure TokenizerError(Pos: TPoint; Text: string);
     procedure InitSystemBlock(Block: TBlock);
@@ -42 +44 @@
 { TParser }
 
-function TParser.ParseBeginEnd(Block: TBlock; var BeginEnd: TBeginEnd): Boolean;
+function TParser.ParseBeginEnd(Block: TBlock; out BeginEnd: TBeginEnd): Boolean;
 var
   Command: TCommand;
@@ -64 +66 @@
 end;
 
-function TParser.ParseFunctionCall(Block: TBlock; var FunctionCall: TFunctionCall
+function TParser.ParseFunctionCall(Block: TBlock; out FunctionCall: TFunctionCall
   ): Boolean;
 var
@@ -97 +99 @@
 end;
 
-function TParser.ParseCommand(Block: TBlock; var Command: TCommand): Boolean;
+function TParser.ParseCommand(Block: TBlock; out Command: TCommand): Boolean;
 var
   BeginEnd: TBeginEnd;
@@ -127 +129 @@
 end;
 
-function TParser.ParseProgram(SystemBlock: TBlock; var Prog: TProgram): Boolean;
+function TParser.ParseProgram(SystemBlock: TBlock; out Prog: TProgram): Boolean;
 var
   Block: TBlock;
@@ -134 +136 @@
   Result := False;
   Prog := TProgram.Create;
+  Prog.SystemBlock.Free;
   Prog.SystemBlock := SystemBlock;
   if Tokenizer.CheckNext('program', tkKeyword) then begin
@@ -144 +147 @@
   if ParseBlock(SystemBlock, Block) then begin
     Result := True;
+    Prog.Block.Free;
     Prog.Block := Block;
     Tokenizer.Expect('.', tkSpecialSymbol);
@@ -152 +156 @@
 end;
 
-function TParser.ParseBlock(ParentBlock: TBlock; var Block: TBlock): Boolean;
-var
-  Token: TToken;
-  Variable: TVariable;
-  Constant: TConstant;
-begin
+function TParser.ParseBlock(ParentBlock: TBlock; out Block: TBlock): Boolean;
+var
+  BeginEnd: TBeginEnd;
+begin
+  Result := False;
   Block := TBlock.Create;
   Block.Parent := ParentBlock;
+  ParseVarBlock(Block);
+  ParseConstBlock(Block);
+  if ParseBeginEnd(Block, BeginEnd) then begin
+    Result := True;
+    Block.BeginEnd.Free;
+    Block.BeginEnd := BeginEnd;
+  end else Block.Free;
+end;
+
+function TParser.ParseVarBlock(Block: TBlock): Boolean;
+var
+  Token: TToken;
+  Variable: TVariable;
+begin
   if Tokenizer.CheckNext('var', tkKeyword) then begin
+    Result := True;
     Tokenizer.Expect('var', tkKeyword);
     while Tokenizer.CheckNextKind(tkIdentifier) do begin
@@ -177 +195 @@
       end;
     end;
-  end;
+  end else Result := False;
+end;
+
+function TParser.ParseConstBlock(Block: TBlock): Boolean;
+var
+  Token: TToken;
+  Constant: TConstant;
+begin
   if Tokenizer.CheckNext('const', tkKeyword) then begin
+    Result := True;
     Tokenizer.Expect('const', tkKeyword);
     while Tokenizer.CheckNextKind(tkIdentifier) do begin
@@ -200 +226 @@
       end;
     end;
-  end;
-  Result := ParseBeginEnd(Block, Block.BeginEnd);
-  //if not Result then Block.Free;
-end;
-
-function TParser.ParseAssignment(Block: TBlock; var Assignment: TAssignment): Boolean;
+  end else Result := False;
+end;
+
+function TParser.ParseAssignment(Block: TBlock; out Assignment: TAssignment): Boolean;
 var
   Token: TToken;
   Variable: TVariable;
+  Expression: TExpression;
 begin
   Result := False;
@@ -220 +245 @@
       Assignment.Variable := Variable;
       Tokenizer.Expect(':=', tkSpecialSymbol);
-      ParseExpression(Block, Assignment.Expression);
+      if ParseExpression(Block, Expression) then begin
+        Assignment.Expression.Free;
+        Assignment.Expression := Expression;
+      end;
     end else Error('Variable ' + Token.Text + ' not defined.');
   end;
 end;
 
-function TParser.ParseExpression(Block: TBlock; var Expression: TExpression
+function TParser.ParseExpression(Block: TBlock; out Expression: TExpression
   ): Boolean;
 var
@@ -239 +267 @@
       Result := True;
       Expression := TExpression.Create;
-      Expression.Variable := Variable;
+      Expression.VariableRef := Variable;
     end else begin
       Constant := Block.Constants.SearchByName(Token.Text);
@@ -245 +273 @@
         Result := True;
         Expression := TExpression.Create;
-        Expression.Constant := Constant;
+        Expression.ConstantRef := Constant;
       end;
     end;
@@ -251 +279 @@
   if Token.Kind = tkNumber then begin
     Result := True;
+    Constant := Block.Constants.AddNew('_C' + IntToStr(Block.Constants.Count));
+    Constant.Value := Token.Text;
     Expression := TExpression.Create;
-    Expression.Constant := TConstant.Create;
-    Expression.Constant.Value := Token.Text;
+    Expression.ConstantRef := Constant;
   end else
   if Token.Kind = tkString then begin
     Result := True;
+    Constant := Block.Constants.AddNew('_C' + IntToStr(Block.Constants.Count));
+    Constant.Value := Token.Text;
     Expression := TExpression.Create;
-    Expression.Constant := TConstant.Create;
-    Expression.Constant.Value := Token.Text;
-  end;
-end;
-
-function TParser.ParseIfThenElse(Block: TBlock; var IfThenElse: TIfThenElse
+    Expression.ConstantRef := Constant;
+  end;
+end;
+
+function TParser.ParseIfThenElse(Block: TBlock; out IfThenElse: TIfThenElse
   ): Boolean;
 var
@@ -275 +305 @@
     IfThenElse := TIfThenElse.Create;
     if ParseExpression(Block, Expression) then begin
+      IfThenElse.Expression.Free;
       IfThenElse.Expression := Expression;
       Tokenizer.Expect('then', tkKeyword);
       if ParseCommand(Block, Command) then begin
+        IfThenElse.CommandThen.Free;
         IfThenElse.CommandThen := Command;
         if Tokenizer.CheckNext('else', tkKeyword) then begin
           Tokenizer.Expect('else', tkKeyword);
           if ParseCommand(Block, Command) then begin
+            IfThenElse.CommandElse.Free;
             IfThenElse.CommandElse := Command;
           end else Error('Expected command');
@@ -290 +323 @@
 end;
 
-function TParser.ParseWhileDo(Block: TBlock; var WhileDo: TWhileDo): Boolean;
+function TParser.ParseWhileDo(Block: TBlock; out WhileDo: TWhileDo): Boolean;
 var
   Expression: TExpression;
@@ -301 +334 @@
     WhileDo := TWhileDo.Create;
     if ParseExpression(Block, Expression) then begin
+      WhileDo.Expression.Free;
       WhileDo.Expression := Expression;
       Tokenizer.Expect('do', tkKeyword);
       if ParseCommand(Block, Command) then begin
+        WhileDo.Command.Free;
         WhileDo.Command := Command;
       end else Error('Expected command');