How to config a simple Go project

Question

I'm trying to follow the Writing an intepreter in Go book, by Thorsten Ball, and in the first chapter he establish this simple scheme

file /Users/myuser/projects/monkey/token/token.go
file /Users/myuser/projects/monkey/lexer/lexer.go
file /Users/myuser/projects/monkey/lexer/lexer_test.go

In lexer/lexer.go and lexer/lexer_test.g the files start as

package lexer

And in lexer_test.go the imports are

import (
    "testing"
    "monkey/token"
)

Then he says that for running the test, I have to run (from /Users/myuser/projects/monkey directory):

go test lexer/lexer_test.go

But when I do this, I receive the error:

lexer/lexer_test.go:6:2: cannot find package "monkey/token" in any of:
    /usr/local/opt/go/libexec/src/monkey/token (from $GOROOT)
    /Users/myuser/golang/src/monkey/token (from $GOPATH)
FAIL    command-line-arguments [setup failed]
FAIL

I've been trying to understand how to configure the packages in go, but I found a lot of very complicated documentation about GOPATH, GOROOT and go.mod. I've been trying all this approach without get rid of the issue.

Can someone help me please? I'm sure is a simple fix but I cannot figure it out :(

Answer 1

As the error message says, the compiler couldn't find the package locally.

Are you sure you have installed the package?

You may need to do go get [packagename]

For e.g., go get golang.org/x/tools/cmd/goimports

Answer 2

For Golang, It will find package first from go root then go path then import from outside. So basically, you should have that package monkey/token in your go root or go path. I don't think it is about goimport because monkey/token didn't seem to be official lib that can be import. When I first try Golang I have the same problem. I solve by create that package in go path (your working dir) or create that package from your book.