Ah yes, the canonical problem when learning a new programming language. I have this:
$GOPATH/
src/
huru/
foo/
side.go
hello.go
in hello.go I have:
package main
import (
"encoding/json"
"log"
"net/http"
"github.com/gorilla/mux"
)
func main(){
Foo()
}
and in foo/side.go, I have:
package main
func Foo() {
}
I run:
go install huru
and I get:
# huru
src/huru/hello.go:22:2: undefined: Foo
the compiler doesn't like the Foo() call in hello.go, how do I import it properly? Should I be using package main for both files? Why wouldn't the package be called huru, I assume I should call the package huru..instead of main? idk.
You must not use main as the package name of huru/foo/side.go, because it's already used in the huru/hello.go where the path is different than where side.go located.
So change the package name on the huru/foo/side.go file. Better to use folder name as the package name.
package foo
func Foo() {
}
Then on the huru/hello.go, import the huru/foo package so you'll be able to consume the Foo() function that defined on the file inside.
package main
import (
"encoding/json"
"log"
"net/http"
"github.com/gorilla/mux"
"huru/foo" // <------ here
)
func main(){
foo.Foo()
}
As described in the Go Documentation, a program is defined by a single unimported main package. You can't have multiple main packages in a program, so if you want to make a library, e.g. your foo dir, you need to define a different package name.
Also included in the documentation is a description for how imports are handled. To be fair, it's a bit cryptic and they don't explicitly mention $GOPATH, but imports are taken relative to it. You can't import a package relative to a specific file, however.
Your code will compile fine if you do something like this:
hello.go:
package main
import . "huru/foo"
func main() {
Foo()
}
foo/side.go:
package foo
import "fmt"
func Foo() {
fmt.Println("Hello from side.go");
}