2 files changed, 49 insertions, 13 deletions

diff --git a/pkg/server/env.go b/pkg/server/env.go
index 7fc338d..2f6937e 100644
--- a/pkg/server/env.go
+++ b/pkg/server/env.go
@@ -10,6 +10,7 @@ func init() {
 	newCmd(envSet,  "env", "set")
 	newCmd(envDel,  "env", "del")
 	newCmd(envShow, "env", "show")
+	newCmd(envClear, "env", "clear")
 }
 
 type env struct {
@@ -17,7 +18,11 @@ type env struct {
 	sync.Mutex
 }
 
-var isValidVarName = regexp.MustCompile("^[a-zA-Z][a-zA-Z0-9]*$").MatchString
+const varNamePattern = "[a-zA-Z][a-zA-Z0-9]*"
+
+var isValidVarName = regexp.MustCompile("^" + varNamePattern + "$").MatchString
+
+var varTokenRe = regexp.MustCompile("%" + varNamePattern)
 
 func (e *env) get(key string) (string, bool) {
 	e.Lock()
@@ -67,6 +72,13 @@ func (e *env) each(f func (string, string) bool) {
 	}
 }
 
+func (e *env) clear() {
+	e.Lock()
+	defer e.Unlock()
+
+	e.m = nil
+}
+
 func envGet(r *request) {
 	r.expect(1)
 
@@ -96,10 +108,12 @@ func envDel(r *request) {
 }
 
 func envShow(r *request) {
-	r.expect(0)
-
 	r.c.s.env.each(func (k string, v string) bool {
 		r.Println(k, v)
 		return true
 	})
 }
+
+func envClear(r *request) {
+	r.c.s.env.clear()
+}
diff --git a/pkg/server/server.go b/pkg/server/server.go
index e2515cb..0524216 100644
--- a/pkg/server/server.go
+++ b/pkg/server/server.go
@@ -245,22 +245,44 @@ func (r *request) decode(query string) []string {
 	return t
 }
 
-func (r *request) parse(query string) {
-	c, args := getCmd(r.decode(query))
-	if c == nil {
-		r.Fatal("command not found")
+func (r *request) eval(args []string) []string {
+	repl := func (v string) string {
+		if v, ok := r.c.s.env.get(v[1:]); ok {
+			return v
+		}
+
+		r.Fatal("unbound variable ", v)
+
+		return v
 	}
 
-	for n, s := range args {
-		if strings.HasPrefix(s, "%") {
-			if v, ok := r.c.s.env.get(s[1:]); ok {
-				args[n] = v
-			} else {
-				r.Fatal("unbound variable ", s)
+	eval := func (s string) string {
+		var t string
+
+		for ;; s = t {
+			t = varTokenRe.ReplaceAllStringFunc(s, repl)
+
+			if s == t {
+				return s
 			}
 		}
 	}
 
+	for n, s := range args {
+		args[n] = eval(s)
+	}
+
+	return args
+}
+
+func (r *request) parse(query string) {
+	args := r.eval(r.decode(query))
+
+	c, args := getCmd(args)
+	if c == nil {
+		r.Fatal("command not found")
+	}
+
 	r.args = args
 	r.argc = len(args)
 	r.cmd = c