void WhileStatement()
{
var surroundingLoopState = InnermostLoop;
InnermostLoop = LoopState.FromCurrentState(this);
Expression();
Consume(TokenType.Colon, "Expect ':' after condition");
var exitJump = EmitJump(OpCode.JumpIfFalse);
Emit(OpCode.Pop);
Statement();
EmitLoop(InnermostLoop.Start);
PatchJump(exitJump);
Emit(OpCode.Pop);
InnermostLoop.PatchUnresolvedBreaks(this);
InnermostLoop = surroundingLoopState;
}
void ForStatement()
{
BeginScope();
// Initializer
if (Match(TokenType.Var))
{
VarDeclaration();
}
else if (Match(TokenType.Semicolon))
{
// No initializer
}
else
{
ExpressionStatement();
}
var surroundingLoopState = InnermostLoop;
InnermostLoop = LoopState.FromCurrentState(this);
// Condition
var exitJump = -1;
if (!Match(TokenType.Semicolon))
{
Expression();
Consume(TokenType.Semicolon, "Expect ';' after loop condition");
// Jump out if condition is negative
exitJump = EmitJump(OpCode.JumpIfFalse);
Emit(OpCode.Pop); // Condition
}
// Increment
if (!Match(TokenType.Colon))
{
var bodyJump = EmitJump(OpCode.Jump);
var incrementStart = CurrentCodePosition();
Expression();
Emit(OpCode.Pop);
Consume(TokenType.Colon, "Expect ':' after for clauses");
EmitLoop(InnermostLoop.Start);
InnermostLoop.Start = incrementStart;
PatchJump(bodyJump);
}
Statement();
EmitLoop(InnermostLoop.Start);
if (exitJump != -1)
{
PatchJump(exitJump);
Emit(OpCode.Pop); // Condition, if Pop has been jumped over above
}
InnermostLoop.PatchUnresolvedBreaks(this);
InnermostLoop = surroundingLoopState;
EndScope();
}
