// VisitExpression implements corresponding Visitor interface method
func (v *evalVisitor) VisitExpression(node *ast.Expression) interface{} {
v.at(node)
var result interface{}
done := false
v.pushExpr(node)
// helper call
if helperName := node.HelperName(); helperName != "" {
if helper := v.findHelper(helperName); helper != zero {
result = v.callHelper(helperName, helper, node)
done = true
}
}
if !done {
// literal
if literal, ok := node.LiteralStr(); ok {
if val := v.evalField(v.curCtx(), literal, true); val.IsValid() {
result = val.Interface()
done = true
}
}
}
if !done {
// field path
if path := node.FieldPath(); path != nil {
// @todo Find a cleaner way ! Don't break the pattern !
// this is an exception to visitor pattern, because we need to pass the info
// that this path is at root of current expression
if val := v.evalPathExpression(path, true); val != nil {
result = val
}
}
}
v.popExpr()
return result
}
// isHelperCall returns true if given expression is a helper call
func (v *evalVisitor) isHelperCall(node *ast.Expression) bool {
if helperName := node.HelperName(); helperName != "" {
return v.findHelper(helperName) != zero
}
return false
}