How Can I Effectively Print Go Structs Containing Fields with String() Methods?

How to Print Structs with Field String() Methods

fmt.Println() prints native representations of structs because they do not implement the String() interface by default. Implementing String() for every struct can be tedious and requires updates when fields are added or removed.

Helper Function for Custom Printing

To address this limitation, you can utilize a helper function that leverages reflection (reflect package):

func PrintStruct(s interface{}, names bool) string {
    // ... // (function body as provided in the answer)
}

This function iterates over struct fields and retrieves String() values if applicable:

fmt.Println(PrintStruct(a, true))

Struct-Specific String() Method

Alternatively, you can define a String() method for your struct that calls the PrintStruct() function:

func (a A) String() string {
    return PrintStruct(a, true)
}

This method handles dynamic changes in struct fields without modifications to the String() method.

Usage

With the helper function or struct-specific String() method, you can conveniently print structs with their field String() values:

// using the PrintStruct() function
fmt.Println(PrintStruct(a, true))

// using the custom String() method (if defined)
fmt.Println(a)

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