using the C pre-processor with Go

gistfile1.txt

laptop:cppgo dgryski$ cat gen.go
package main

//go:generate cpp-7 -E -P foo.gopp foo.go
laptop:cppgo dgryski$ cat foo.gopp
package main

import "fmt"

#define STRINGIFY(x) #x
#define TOSTRING(x) STRINGIFY(x)
#define AT __FILE__+":"+TOSTRING(__LINE__)
#define OUT(...) fmt.Println(AT, __VA_ARGS__)
#define ERR(e) if e != nil { return e }

func greeting() (string, error) {
	return "hello", nil
}

func print() error {
	s, err := greeting()
	ERR(err)
	OUT(s)
	return nil
}

func main() {
	print()
}

laptop:cppgo dgryski$ go generate
laptop:cppgo dgryski$ cat foo.go
package main
import "fmt"
func greeting() (string, error) {
 return "hello", nil
}
func print() error {
 s, err := greeting()
 if err != nil { return err }
 fmt.Println("foo.gopp"+":"+"21", s)
 return nil
}
func main() {
 print()
}
laptop:cppgo dgryski$ go run foo.go
foo.gopp:21 hello

I had 5 mins of free time and I wanted to give it a try (with no Go experience whatsoever) so I made a small cast using asciinema 👍