CiExpr ParseRelExpr()
{
CiExpr left = ParseShiftExpr();
while (See(CiToken.Less) || See(CiToken.LessOrEqual) || See(CiToken.Greater) || See(CiToken.GreaterOrEqual)) {
CiToken op = this.CurrentToken;
NextToken();
left = new CiBoolBinaryExpr { Left = left, Op = op, Right = ParseShiftExpr() };
}
return left;
}
CiExpr ParseCondOrExpr()
{
CiExpr left = ParseCondAndExpr();
while (Eat(CiToken.CondOr))
left = new CiBoolBinaryExpr { Left = left, Op = CiToken.CondOr, Right = ParseCondAndExpr() };
return left;
}
CiExpr ParseEqualityExpr()
{
CiExpr left = ParseRelExpr();
while (See(CiToken.Equal) || See(CiToken.NotEqual)) {
CiToken op = this.CurrentToken;
NextToken();
left = new CiBoolBinaryExpr { Left = left, Op = op, Right = ParseRelExpr() };
}
return left;
}
CiExpr ICiExprVisitor.Visit(CiBoolBinaryExpr expr)
{
CiExpr left = Resolve(expr.Left);
CiExpr right = Resolve(expr.Right);
CiType type;
switch (expr.Op) {
case CiToken.CondAnd:
case CiToken.CondOr:
type = CiBoolType.Value;
break;
case CiToken.Equal:
case CiToken.NotEqual:
type = FindCommonType(left, right);
break;
default:
type = CiIntType.Value;
break;
}
expr.Left = Coerce(left, type);
expr.Right = Coerce(right, type);
CiConstExpr cleft = expr.Left as CiConstExpr;
if (cleft != null) {
switch (expr.Op) {
case CiToken.CondAnd:
return (bool) cleft.Value ? expr.Right : new CiConstExpr(false);
case CiToken.CondOr:
return (bool) cleft.Value ? new CiConstExpr(true) : expr.Right;
case CiToken.Equal:
case CiToken.NotEqual:
CiConstExpr cright = expr.Right as CiConstExpr;
if (cright != null) {
bool eq = object.Equals(cleft.Value, cright.Value);
return new CiConstExpr(expr.Op == CiToken.Equal ? eq : !eq);
}
break;
default:
if (expr.Right is CiConstExpr) {
int a = GetConstInt(cleft);
int b = GetConstInt(expr.Right);
bool result;
switch (expr.Op) {
case CiToken.Less: result = a < b; break;
case CiToken.LessOrEqual: result = a <= b; break;
case CiToken.Greater: result = a > b; break;
case CiToken.GreaterOrEqual: result = a >= b; break;
default: return expr;
}
return new CiConstExpr(result);
}
break;
}
}
return expr;
}
