Constant struct in Go

Go

Go Problem Overview

Why can't I create constant struct?

const FEED_TO_INSERT = quzx.RssFeed{ 0,
				    "",
				    "desc",
	                "www.some-site.com",
				    "upd_url",
				    "img_title",
				    "img_url",
				    0,
				    0,
				    0,
				    0,
				    0,
				    100,
				    "alt_name",
				    1,
				    1,
				    1,
				    "test",
				    100,
				    100,
				    0 }

> .\rss_test.go:32: const initializer quzx.RssFeed literal is not a constant

Go Solutions

Solution 1 - Go

Because Go does not support struct constants (emphasis mine)

> There are boolean constants, rune constants, integer constants, > floating-point constants, complex constants, and string constants. > Rune, integer, floating-point, and complex constants are collectively > called numeric constants.

Read more here: https://golang.org/ref/spec#Constants

Solution 2 - Go

A good workaround is to wrap it in a function.

func FEED_TO_INSERT() quzx.RssFeed {
    return quzx.RssFeed{ 0,
                    "",
                    "desc",
                    "www.some-site.com",
                    "upd_url",
                    "img_title",
                    "img_url",
                    0,
                    0,
                    0,
                    0,
                    0,
                    100,
                    "alt_name",
                    1,
                    1,
                    1,
                    "test",
                    100,
                    100,
                    0 }
}

Note: Make sure that the function is always returning a new object(or copy).

Solution 3 - Go

You should declare it as a var.

Go allows you to declare and initialize global variables at module scope.

Go does not have any concept of immutability. 'const' is not meant as a way to prevent variables from mutating or anything like that.

Categories
Recommended Go Solutions

Previous Solution:

How can I see Dockerfile for each docker image?

DockerDockerfile

Next Solution:

Which shell I am using in mac

BashMacosShellUnixZsh

Attributions

All content for this solution is sourced from the original question on Stackoverflow.

The content on this page is licensed under the Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license.

Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestioncethView Question on Stackoverflow
Solution 1 - GomkoprivaView Answer on Stackoverflow
Solution 2 - GoIhorView Answer on Stackoverflow
Solution 3 - Gouser10753492View Answer on Stackoverflow