[go-nuts] Compiler complains "undefined variable" when the variable is defined within a switch block

On Sunday, January 12, 2014 8:12:41 PM UTC+2, AKU wrote:

Hi

I have a Form struct which holds a map of FormFields and a method to add
FormField structs.

The method to add FormField looks as follows:
func (f *Form) addField(fieldtype,fieldname string) {
switch fieldtype {
case "text":
ff := new(FormField_text)
case "hidden":
ff := new(FormField_hidden)
}
ff.name = fieldname
// ... more fields to be filled and things to be done identical for all
ff's
f.fields[fieldname] = ff
}

Problem: The compiler says that "fieldname" can not be assigned because
"ff" is not defined.

I can of course define "ff" outside the switch block using an interface:
func (f *Form) addField(fieldtype,fieldname string) {
var ff FormFieldInterface
switch fieldtype {
case "text":
ff = new(FormField_text)
case "hidden":
ff = new(FormField_hidden)
}
ff.name = fieldname
// ... more fields to be filled and things to be done identical for all
ff's
f.fields[fieldname] = ff
}

Problem: Now the compiler complains that the interface FormFieldInterface
has no field "name". That's correct, of course because I can not define the
fields for the interface but only for the structs that implement that
interface.

Obviously I do not want to repeat assignements and actions for the ff's
inside each switch case. But right now this seems to be the only working
solution.
Can anybody help me what I could do instead?

I have been programmed PHP and Javascript so far. Therefore, I am sorry if
this is a beginners question. All hints are highly appreciated.

Adrian

On Jan 12, 2014 1:54 PM, "AKU" wrote:
You are right. In fact, the struct fields ARE different depending on the
FormField type.
I will try using an init() method which I can implement specifically for

On Sunday, January 12, 2014, AKU wrote:

Hi

I have a Form struct which holds a map of FormFields and a method to add
FormField structs.

The method to add FormField looks as follows:
func (f *Form) addField(fieldtype,fieldname string) {
switch fieldtype {
case "text":
ff := new(FormField_text)
case "hidden":
ff := new(FormField_hidden)
}
ff.name = fieldname
// ... more fields to be filled and things to be done identical for all
ff's
f.fields[fieldname] = ff
}

Problem: The compiler says that "fieldname" can not be assigned because
"ff" is not defined.

I can of course define "ff" outside the switch block using an interface:
func (f *Form) addField(fieldtype,fieldname string) {
var ff FormFieldInterface
switch fieldtype {
case "text":
ff = new(FormField_text)
case "hidden":
ff = new(FormField_hidden)
}
ff.name = fieldname
// ... more fields to be filled and things to be done identical for all
ff's
f.fields[fieldname] = ff
}

Problem: Now the compiler complains that the interface FormFieldInterface
has no field "name". That's correct, of course because I can not define the
fields for the interface but only for the structs that implement that
interface.

Obviously I do not want to repeat assignements and actions for the ff's
inside each switch case. But right now this seems to be the only working
solution.
Can anybody help me what I could do instead?

I have been programmed PHP and Javascript so far. Therefore, I am sorry if
this is a beginners question. All hints are highly appreciated.

Adrian

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