end result

>                                          tulip:navi go 🌱  master 🍂  9e7fbf5

main.go

package main

import (
	"fmt"
	"os"
	"os/exec"
	"strings"

	"github.com/michaelschade/gozsh/zshprompt"
)

func main() {
	pb := &zshprompt.PromptBuilder{}
	pb.PushColoredText(zshprompt.Magenta, "%m:")

	// make go codepaths special ^.^
	if strings.HasPrefix(os.Getenv("PWD"), os.Getenv("GOPATH")) {
		pb.PushColoredText(zshprompt.White, "%1d")
		pb.PushColoredText(zshprompt.Red, " go")
	} else {
		pb.PushColoredText(zshprompt.White, "%2d")
	}

	// git branch name
	status := exec.Command("git", "rev-parse", "--abbrev-ref", "HEAD")
	status.Dir = os.Getenv("PWD")
	if output, err := status.Output(); err == nil {
		branch := string(output[:len(output)-1])
		pb.PushColoredText(zshprompt.Red, " 🌱  "+branch)
	}

	// git commit hash
	commit := exec.Command("git", "rev-parse", "--short", "HEAD")
	commit.Dir = os.Getenv("PWD")
	if output, err := commit.Output(); err == nil {
		sha := string(output[:len(output)-1])
		pb.PushColoredText(zshprompt.Yellow, " 🍂  "+sha)
	}

	pb.PushColor(zshprompt.White)
	fmt.Print(pb.BuildPrompt())
}

prompt_builder.go

package zshprompt

import (
	"fmt"
	"strings"
)

type PromptBuilder struct {
	texts []string
}

const (
	Black = iota
	Red
	Green
	Yellow
	Blue
	Magenta
	Cyan
	White
)

// Adds colored text to the list of zsh prompt text. Text can include the
// standard zsh prompt expansions:
//
// 		http://zsh.sourceforge.net/Doc/Release/Prompt-Expansion.html
func (pb *PromptBuilder) PushColoredText(color int, text string) {
	pb.PushColor(color)
	pb.PushText(text)
}

// Queues up a color change on the list of zsh prompt text.
func (pb *PromptBuilder) PushColor(color int) {
	text := fmt.Sprintf("%%F{%d}", color)
	pb.PushText(text)
}

// Adds arbitrary text to the list of zsh prompt text. Text can include the
// standard zsh prompt expansions:
//
// 		http://zsh.sourceforge.net/Doc/Release/Prompt-Expansion.html

func (pb *PromptBuilder) PushText(text string) {
	pb.texts = append(pb.texts, text)
}

// Joins the list of prompt texts together into a string ready for use.
func (pb *PromptBuilder) BuildPrompt() string {
	return strings.Join(pb.texts, "")
}