func (this *JSConverter) Visit(expr expression.Expression) string {
var buf bytes.Buffer
s, err := expr.Accept(this)
if err != nil {
panic(fmt.Sprintf("Unexpected error in JSConverter: %v", err))
}
switch s := s.(type) {
case []byte:
buf.WriteString(string(s))
for this.stack.Size() != 0 {
funcExpr := this.stack.Pop().(*funcExpr)
buf.WriteString(funcExpr.name)
if funcExpr.operands.Front() != nil {
buf.WriteString(writeOperands(funcExpr.operands))
}
}
default:
buf.WriteString(s.(string))
}
// if the stack is not empty, pop the function
/*
for this.stack.Size() != 0 {
funcExpr := this.stack.Pop().(*funcExpr)
buf.WriteString(funcExpr.name)
if funcExpr.operands.Front() != nil {
buf.WriteString(writeOperands(funcExpr.operands))
}
}
*/
return buf.String()
}
func SargableFor(expr1, expr2 expression.Expression) bool {
if expr2.Value() != nil {
return false
}
s := newSargable(expr1)
result, _ := expr2.Accept(s)
return result.(bool)
}
func SubsetOf(expr1, expr2 expression.Expression) bool {
v2 := expr2.Value()
if v2 != nil {
return v2.Truth()
}
s := newSubset(expr1)
result, _ := expr2.Accept(s)
return result.(bool)
}
func SargFor(expr1, expr2 expression.Expression) Spans {
if expr2.Value() != nil {
return nil
}
s := newSarg(expr1)
result, _ := expr2.Accept(s)
if result != nil {
return result.(Spans)
}
return nil
}
func newSarg(expr expression.Expression) expression.Visitor {
s, _ := expr.Accept(_SARG_FACTORY)
return s.(expression.Visitor)
}
func newSubset(expr expression.Expression) expression.Visitor {
s, _ := expr.Accept(_SUBSET_FACTORY)
return s.(expression.Visitor)
}