Resolve bash/shell variables. Format variables as in bash\shell

README.md

https://play.golang.org/p/xJN8MHWIHwI

Resolve bash/shell variables. Format variables as in bash\shell

TODO:

• default value ${A:-default value}

main.go

package main

import (
  "bytes"
  "fmt"
)

func main() {
  params := map[string]string{
    "a": "1",
    "b": "2",
  }
  
  fmt.Println(Format("a=${a} b=${b} c=${c} d=${d}", params))
}

func Format(format string, params map[string]string) string {
	if params == nil {
		params = map[string]string{}
	}

	buf := new(bytes.Buffer)
	entered := false
	start := 0
	for pos, char := range format {
		switch char {
		case '$':
			if format[pos+1] == '{' {
				entered = true
				start = pos + 2
			}
		case '}':
			if entered {
				paramName := format[start:pos]
				entered = false
				buf.WriteString(params[paramName])
			}
		default:
			if !entered {
				buf.WriteRune(char)
			}
		}
	}

	return buf.String()
}