Generic function for setting fields of different structures used as mapped values

php editor Strawberry will introduce to you a very practical general function, which can be used to set fields of different structures to mapped values. This function can help us be more flexible and convenient when processing data, and is no longer limited by the structure of the field. Whether it is an array, object or other data type, this function can be used to implement field mapping operations, improving our development efficiency and code maintainability. If you often need to process fields of different structures, you might as well try this general function, I believe it will bring you a lot of help!

Question content

Having a structure with common fields...

type definition struct {
        id string
        ...
}
type requirement struct {
        id string
        ...
}
type campaign struct {
        id string
        ...
}

...I have multiple functions like this:

func filldefinitionids(values *map[string]definition) {           
        for key, value:=range *values { // repeated code
                value.id=key            // repeated code
                (*values)[key]=value    // repeated code
        }                               // repeated code
}
func fillrequirementids(values *map[string]requirement) {           
        for key, value:=range *values { // repeated code
                value.id=key            // repeated code
                (*values)[key]=value    // repeated code
        }                               // repeated code
}
func fillcampaignids(values *map[string]campaign) {           
        for key, value:=range *values { // repeated code
                value.id=key            // repeated code
                (*values)[key]=value    // repeated code
        }                               // repeated code
}

I want a single function that generalizes access with generics (or interfaces, etc.), kind of...

func fillIds[T Definition|Requirement|Campaign](values *map[string]T) {           
        for key, value:=range *values {
                value.Id=key
                (*values)[key]=value
        }                                
}

Of course, this results in value.id being undefined (type t has no field or method id) . I've been able to overcome similar problems many times, but this time I can't find a solution.

How to abstract this set of functions into one function?

Solution

type definition struct {
    id string
}
type requirement struct {
    id string
}
type campaign struct {
    id string
}

func (v definition) withid(id string) definition   { v.id = id; return v }
func (v requirement) withid(id string) requirement { v.id = id; return v }
func (v campaign) withid(id string) campaign       { v.id = id; return v }

type withid[t any] interface {
    withid(id string) t
}

func fillids[t withid[t]](values map[string]t) {
    for key, value := range values {
        values[key] = value.withid(key)
    }
}

func main() {
    m1 := map[string]definition{"foo": {}, "bar": {}}
    fillids(m1)
    fmt.println(m1)

    m2 := map[string]campaign{"abc": {}, "def": {}}
    fillids(m2)
    fmt.println(m2)
}

https://www.php.cn/link/0db32de7aed05af092becfc3789e7700

An alternative to @blackgreen's answer if you need to use value mapping.

type common struct {
    id string
}

func (v *common) setid(id string) { v.id = id }

type definition struct {
    common
}
type requirement struct {
    common
}
type campaign struct {
    common
}

type idsetter[t any] interface {
    *t
    setid(id string)
}

func fillids[t any, u idsetter[t]](values map[string]t) {
    for key, value := range values {
        u(&value).setid(key)
        values[key] = value
    }
}

func main() {
    m1 := map[string]definition{"foo": {}, "bar": {}}
    fillids(m1)
    fmt.println(m1)

    m2 := map[string]campaign{"abc": {}, "def": {}}
    fillids(m2)
    fmt.println(m2)
}

https://www.php.cn/link/fec3392b0dc073244d38eba1feb8e6b7

The above is the detailed content of Generic function for setting fields of different structures used as mapped values. For more information, please follow other related articles on the PHP Chinese website!