/// <summary>
/// Relation ::= Expression ("<" | ">" | "==" | "!=") Expression.
/// </summary>
/// <returns></returns>
private RELATION parseRelation()
{
RELATION result = new RELATION();
result.expression1 = parseExpression();
Token token = lexer.get();
switch ( token.code )
{
case TokenCode.LESS :
case TokenCode.GREATER :
case TokenCode.EQUAL :
case TokenCode.NOT_EQUAL :
result.op = token.code;
lexer.forget();
result.expression2 = parseExpression();
break;
default:
errors.issue(token,23);
lexer.skipUntil(TokenCode.SEMICOLON);
break;
}
return result;
}
private void generateRelation( ILGenerator il, RELATION relation, Label labelFalse )
{
generateExpression(il,relation.expression1);
generateExpression(il,relation.expression2);
switch ( relation.op )
{
case TokenCode.LESS: il.Emit(OpCodes.Bge, labelFalse); break;
case TokenCode.GREATER: il.Emit(OpCodes.Ble, labelFalse); break;
case TokenCode.EQUAL: il.Emit(OpCodes.Bne_Un,labelFalse); break;
case TokenCode.NOT_EQUAL: il.Emit(OpCodes.Beq, labelFalse); break;
}
}