//
// ifStatement: 'if' '(' expression ')' '{' statements '}' ('else' '{' statements '}' )?
public void CompileIfStatement(int depth)
{
string startLabel = "LIF_" + IfLabelCounter;
string endLabel = "LIF_" + IfLabelCounter;
// compile: 'if'
var ifToken = Eat("if");
// compile: '('
var leftParenToken = Eat("(");
// compile: expression
CompileExpression(depth + 1, AssignmentType.NONE);
// write: not , if-goto startLabel
_vmWriter.WriteUnaryOp(new Token {
Value = "~"
});
_vmWriter.WriteIfGoto(startLabel);
// compile: ')'
var rightParenToken = Eat(")");
// compile: '{'
var leftBraceToken = Eat("{");
// compile: statements
CompileStatements(depth + 1);
// write: goto endLabel
_vmWriter.WriteGoto(endLabel);
// write: label startLabel
_vmWriter.WriteLabel(startLabel);
// compile: '}'
var rightBraceToken = Eat("}");
// compile: ('else' '{' statements '}' )?
if (_tokenizer.CurrentToken.Value == "else")
{
// compile: 'else'
var elseToken = Eat("else");
// compile: '{'
leftBraceToken = Eat("{");
// compile: statements
CompileStatements(depth + 1);
// compile: '}'
rightBraceToken = Eat("}");
}
// write: endLabel
_vmWriter.WriteLabel(endLabel);
}