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|
package env
import (
"errors"
"regexp"
"sync"
)
type env struct {
m map[string]string
sync.Mutex
}
type Env struct {
*env
}
const namePattern = "[a-zA-Z][a-zA-Z0-9]*"
var isNamePattern = regexp.MustCompile("^" + namePattern + "$").MatchString
var namePatternRe = regexp.MustCompile("@" + namePattern)
var errBadVariable = errors.New("bad variable name")
func New() Env {
return Env{new(env)}
}
func (e *env) Find(key string) (string, bool) {
e.Lock()
defer e.Unlock()
v, ok := e.m[key]
return v, ok
}
func (e *env) Get(key string) string {
v, _ := e.Find(key)
return v
}
func (e *env) Set(key string, value string) error {
if !isNamePattern(key) {
return errBadVariable
}
e.Lock()
defer e.Unlock()
if e.m == nil {
e.m = make(map[string]string)
}
e.m[key] = value
return nil
}
func (e *env) Del(key string) bool {
e.Lock()
defer e.Unlock()
if e.m == nil {
return false
}
if _, ok := e.m[key]; !ok {
return false
}
delete(e.m, key)
return true
}
func (e *env) Each(f func (string, string) bool) {
e.Lock()
defer e.Unlock()
for k, v := range e.m {
if !f(k, v) {
break
}
}
}
func (e *env) Clear() {
e.Lock()
defer e.Unlock()
e.m = nil
}
func (e *env) Eval(s string) string {
e.Lock()
defer e.Unlock()
repl := func (v string) string {
if v, ok := e.m[v[1:]]; ok {
return v
}
return ""
}
for {
if t := namePatternRe.ReplaceAllStringFunc(s, repl); t == s {
break
} else {
s = t
}
}
return s
}
|
