All: add keywords.

Also, fix nth and count to match cloure.

13 files changed, 103 insertions, 77 deletions

diff --git a/go/src/core/core.go b/go/src/core/core.go
index 17e92f0..2acca69 100644
--- a/go/src/core/core.go
+++ b/go/src/core/core.go
@@ -140,7 +140,11 @@ func concat(a []MalType) (MalType, error) {
 func nth(a []MalType) (MalType, error) {
     slc, e := GetSlice(a[0]); if e != nil { return nil, e }
     idx := a[1].(int)
-    return slc[idx], nil
+    if idx < len(slc) {
+        return slc[idx], nil
+    } else {
+        return nil, errors.New("nth: index out of range")
+    }
 }
 
 func first(a []MalType) (MalType, error) {
@@ -294,8 +298,14 @@ var NS = map[string]MalType{
             return True_Q(a[0]), nil },
     "false?": func(a []MalType) (MalType, error) {
             return False_Q(a[0]), nil },
+    "symbol":  func(a []MalType) (MalType, error) {
+            return Symbol{a[0].(string)}, nil },
     "symbol?":  func(a []MalType) (MalType, error) {
             return Symbol_Q(a[0]), nil },
+    "keyword":  func(a []MalType) (MalType, error) {
+            return NewKeyword(a[0].(string)) },
+    "keyword?":  func(a []MalType) (MalType, error) {
+            return Keyword_Q(a[0]), nil },
 
     "pr-str": func(a []MalType) (MalType, error) { return pr_str(a) },
     "str": func(a []MalType) (MalType, error) { return str(a) },
diff --git a/go/src/env/env.go b/go/src/env/env.go
index 4d20857..584c9a7 100644
--- a/go/src/env/env.go
+++ b/go/src/env/env.go
@@ -35,8 +35,8 @@ func NewEnv(outer EnvType, binds_mt MalType, exprs_mt MalType) (EnvType, error)
     return env, nil
 }
 
-func (e Env) Find(key string) EnvType {
-    if _, ok := e.data[key]; ok {
+func (e Env) Find(key Symbol) EnvType {
+    if _, ok := e.data[key.Val]; ok {
         return e
     } else if (e.outer != nil) {
         return e.outer.Find(key)
@@ -45,15 +45,15 @@ func (e Env) Find(key string) EnvType {
     }
 }
 
-func (e Env) Set(key string, value MalType) MalType {
-    e.data[key] = value
+func (e Env) Set(key Symbol, value MalType) MalType {
+    e.data[key.Val] = value
     return value
 }
 
-func (e Env) Get(key string) (MalType, error) {
+func (e Env) Get(key Symbol) (MalType, error) {
     env := e.Find(key)
     if env == nil {
-        return nil, errors.New("'" + key + "' not found")
+        return nil, errors.New("'" + key.Val + "' not found")
     }
-    return env.(Env).data[key], nil
+    return env.(Env).data[key.Val], nil
 }
diff --git a/go/src/printer/printer.go b/go/src/printer/printer.go
index 428958e..1b8e9fe 100644
--- a/go/src/printer/printer.go
+++ b/go/src/printer/printer.go
@@ -32,7 +32,9 @@ func Pr_str(obj types.MalType, print_readably bool) string {
         }
         return "{" + strings.Join(str_list, " ") + "}"
     case string:
-        if print_readably {
+        if strings.HasPrefix(tobj, "\u029e") {
+            return ":" + tobj[2:len(tobj)]
+        } else if print_readably {
             return `"` + strings.Replace(
                            strings.Replace(
                              strings.Replace(tobj,`\`,`\\`, -1),
diff --git a/go/src/reader/reader.go b/go/src/reader/reader.go
index 6fbe311..9cacb8b 100644
--- a/go/src/reader/reader.go
+++ b/go/src/reader/reader.go
@@ -64,6 +64,8 @@ func read_atom(rdr Reader) (MalType, error) {
         return strings.Replace(
                  strings.Replace(str, `\"`, `"`, -1),
                  `\n`, "\n", -1), nil
+    } else if (*token)[0] == ':' {
+        return NewKeyword((*token)[1:len(*token)])
     } else if *token == "nil" {
         return nil, nil
     } else if *token == "true" {
diff --git a/go/src/step3_env/step3_env.go b/go/src/step3_env/step3_env.go
index 0d975ba..0c45bf2 100644
--- a/go/src/step3_env/step3_env.go
+++ b/go/src/step3_env/step3_env.go
@@ -23,7 +23,7 @@ func READ(str string) (MalType, error) {
 func eval_ast(ast MalType, env EnvType) (MalType, error) {
     //fmt.Printf("eval_ast: %#v\n", ast)
     if Symbol_Q(ast) {
-        return env.Get(ast.(Symbol).Val)
+        return env.Get(ast.(Symbol))
     } else if List_Q(ast) {
         lst := []MalType{}
         for _, a := range ast.(List).Val {
@@ -83,7 +83,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
     case "def!":
         res, e := EVAL(a2, env)
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, res), nil
+        return env.Set(a1.(Symbol), res), nil
     case "let*":
         let_env, e := NewEnv(env, nil, nil)
         if e != nil { return nil, e }
@@ -95,7 +95,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
             }
             exp, e := EVAL(arr1[i+1], let_env)
             if e != nil { return nil, e }
-            let_env.Set(arr1[i].(Symbol).Val, exp)
+            let_env.Set(arr1[i].(Symbol), exp)
         }
         return EVAL(a2, let_env)
     default:
@@ -127,13 +127,13 @@ func rep(str string) (MalType, error) {
 }
 
 func main() {
-    repl_env.Set("+", func(a []MalType) (MalType, error) {
+    repl_env.Set(Symbol{"+"}, func(a []MalType) (MalType, error) {
         return a[0].(int) + a[1].(int), nil })
-    repl_env.Set("-", func(a []MalType) (MalType, error) {
+    repl_env.Set(Symbol{"-"}, func(a []MalType) (MalType, error) {
         return a[0].(int) - a[1].(int), nil })
-    repl_env.Set("*", func(a []MalType) (MalType, error) {
+    repl_env.Set(Symbol{"*"}, func(a []MalType) (MalType, error) {
         return a[0].(int) * a[1].(int), nil })
-    repl_env.Set("/", func(a []MalType) (MalType, error) {
+    repl_env.Set(Symbol{"/"}, func(a []MalType) (MalType, error) {
         return a[0].(int) / a[1].(int), nil })
 
     // repl loop
diff --git a/go/src/step4_if_fn_do/step4_if_fn_do.go b/go/src/step4_if_fn_do/step4_if_fn_do.go
index f63017b..d90a720 100644
--- a/go/src/step4_if_fn_do/step4_if_fn_do.go
+++ b/go/src/step4_if_fn_do/step4_if_fn_do.go
@@ -24,7 +24,7 @@ func READ(str string) (MalType, error) {
 func eval_ast(ast MalType, env EnvType) (MalType, error) {
     //fmt.Printf("eval_ast: %#v\n", ast)
     if Symbol_Q(ast) {
-        return env.Get(ast.(Symbol).Val)
+        return env.Get(ast.(Symbol))
     } else if List_Q(ast) {
         lst := []MalType{}
         for _, a := range ast.(List).Val {
@@ -84,7 +84,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
     case "def!":
         res, e := EVAL(a2, env)
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, res), nil
+        return env.Set(a1.(Symbol), res), nil
     case "let*":
         let_env, e := NewEnv(env, nil, nil)
         if e != nil { return nil, e }
@@ -96,7 +96,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
             }
             exp, e := EVAL(arr1[i+1], let_env)
             if e != nil { return nil, e }
-            let_env.Set(arr1[i].(Symbol).Val, exp)
+            let_env.Set(arr1[i].(Symbol), exp)
         }
         return EVAL(a2, let_env)
     case "do":
@@ -154,7 +154,7 @@ func rep(str string) (MalType, error) {
 func main() {
     // core.go: defined using go
     for k, v := range core.NS {
-        repl_env.Set(k, v)
+        repl_env.Set(Symbol{k}, v)
     }
 
     // core.mal: defined using the language itself
diff --git a/go/src/step5_tco/step5_tco.go b/go/src/step5_tco/step5_tco.go
index 9e176bb..8c6ff37 100644
--- a/go/src/step5_tco/step5_tco.go
+++ b/go/src/step5_tco/step5_tco.go
@@ -24,7 +24,7 @@ func READ(str string) (MalType, error) {
 func eval_ast(ast MalType, env EnvType) (MalType, error) {
     //fmt.Printf("eval_ast: %#v\n", ast)
     if Symbol_Q(ast) {
-        return env.Get(ast.(Symbol).Val)
+        return env.Get(ast.(Symbol))
     } else if List_Q(ast) {
         lst := []MalType{}
         for _, a := range ast.(List).Val {
@@ -86,7 +86,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
     case "def!":
         res, e := EVAL(a2, env)
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, res), nil
+        return env.Set(a1.(Symbol), res), nil
     case "let*":
         let_env, e := NewEnv(env, nil, nil)
         if e != nil { return nil, e }
@@ -98,7 +98,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
             }
             exp, e := EVAL(arr1[i+1], let_env)
             if e != nil { return nil, e }
-            let_env.Set(arr1[i].(Symbol).Val, exp)
+            let_env.Set(arr1[i].(Symbol), exp)
         }
         ast = a2
         env = let_env
@@ -164,7 +164,7 @@ func rep(str string) (MalType, error) {
 func main() {
     // core.go: defined using go
     for k, v := range core.NS {
-        repl_env.Set(k, Func{v.(func([]MalType)(MalType,error)),nil})
+        repl_env.Set(Symbol{k}, Func{v.(func([]MalType)(MalType,error)),nil})
     }
 
     // core.mal: defined using the language itself
diff --git a/go/src/step6_file/step6_file.go b/go/src/step6_file/step6_file.go
index 748d158..701ac47 100644
--- a/go/src/step6_file/step6_file.go
+++ b/go/src/step6_file/step6_file.go
@@ -25,7 +25,7 @@ func READ(str string) (MalType, error) {
 func eval_ast(ast MalType, env EnvType) (MalType, error) {
     //fmt.Printf("eval_ast: %#v\n", ast)
     if Symbol_Q(ast) {
-        return env.Get(ast.(Symbol).Val)
+        return env.Get(ast.(Symbol))
     } else if List_Q(ast) {
         lst := []MalType{}
         for _, a := range ast.(List).Val {
@@ -87,7 +87,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
     case "def!":
         res, e := EVAL(a2, env)
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, res), nil
+        return env.Set(a1.(Symbol), res), nil
     case "let*":
         let_env, e := NewEnv(env, nil, nil)
         if e != nil { return nil, e }
@@ -99,7 +99,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
             }
             exp, e := EVAL(arr1[i+1], let_env)
             if e != nil { return nil, e }
-            let_env.Set(arr1[i].(Symbol).Val, exp)
+            let_env.Set(arr1[i].(Symbol), exp)
         }
         ast = a2
         env = let_env
@@ -165,11 +165,11 @@ func rep(str string) (MalType, error) {
 func main() {
     // core.go: defined using go
     for k, v := range core.NS {
-        repl_env.Set(k, Func{v.(func([]MalType)(MalType,error)),nil})
+        repl_env.Set(Symbol{k}, Func{v.(func([]MalType)(MalType,error)),nil})
     }
-    repl_env.Set("eval", Func{func(a []MalType) (MalType, error) {
+    repl_env.Set(Symbol{"eval"}, Func{func(a []MalType) (MalType, error) {
         return EVAL(a[0], repl_env) },nil})
-    repl_env.Set("*ARGV*", List{})
+    repl_env.Set(Symbol{"*ARGV*"}, List{})
 
     // core.mal: defined using the language itself
     rep("(def! not (fn* (a) (if a false true)))")
@@ -181,7 +181,7 @@ func main() {
         for _,a := range os.Args[2:] {
             args = append(args, a)
         }
-        repl_env.Set("*ARGV*", List{args,nil})
+        repl_env.Set(Symbol{"*ARGV*"}, List{args,nil})
         if _,e := rep("(load-file \"" + os.Args[1] + "\")"); e != nil {
             fmt.Printf("Error: %v\n", e)
             os.Exit(1)
diff --git a/go/src/step7_quote/step7_quote.go b/go/src/step7_quote/step7_quote.go
index 999129e..d93f620 100644
--- a/go/src/step7_quote/step7_quote.go
+++ b/go/src/step7_quote/step7_quote.go
@@ -54,7 +54,7 @@ func quasiquote(ast MalType) MalType {
 func eval_ast(ast MalType, env EnvType) (MalType, error) {
     //fmt.Printf("eval_ast: %#v\n", ast)
     if Symbol_Q(ast) {
-        return env.Get(ast.(Symbol).Val)
+        return env.Get(ast.(Symbol))
     } else if List_Q(ast) {
         lst := []MalType{}
         for _, a := range ast.(List).Val {
@@ -116,7 +116,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
     case "def!":
         res, e := EVAL(a2, env)
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, res), nil
+        return env.Set(a1.(Symbol), res), nil
     case "let*":
         let_env, e := NewEnv(env, nil, nil)
         if e != nil { return nil, e }
@@ -128,7 +128,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
             }
             exp, e := EVAL(arr1[i+1], let_env)
             if e != nil { return nil, e }
-            let_env.Set(arr1[i].(Symbol).Val, exp)
+            let_env.Set(arr1[i].(Symbol), exp)
         }
         ast = a2
         env = let_env
@@ -198,11 +198,11 @@ func rep(str string) (MalType, error) {
 func main() {
     // core.go: defined using go
     for k, v := range core.NS {
-        repl_env.Set(k, Func{v.(func([]MalType)(MalType,error)),nil})
+        repl_env.Set(Symbol{k}, Func{v.(func([]MalType)(MalType,error)),nil})
     }
-    repl_env.Set("eval", Func{func(a []MalType) (MalType, error) {
+    repl_env.Set(Symbol{"eval"}, Func{func(a []MalType) (MalType, error) {
         return EVAL(a[0], repl_env) },nil})
-    repl_env.Set("*ARGV*", List{})
+    repl_env.Set(Symbol{"*ARGV*"}, List{})
 
     // core.mal: defined using the language itself
     rep("(def! not (fn* (a) (if a false true)))")
@@ -214,7 +214,7 @@ func main() {
         for _,a := range os.Args[2:] {
             args = append(args, a)
         }
-        repl_env.Set("*ARGV*", List{args,nil})
+        repl_env.Set(Symbol{"*ARGV*"}, List{args,nil})
         if _,e := rep("(load-file \"" + os.Args[1] + "\")"); e != nil {
             fmt.Printf("Error: %v\n", e)
             os.Exit(1)
diff --git a/go/src/step8_macros/step8_macros.go b/go/src/step8_macros/step8_macros.go
index 3264159..86db33b 100644
--- a/go/src/step8_macros/step8_macros.go
+++ b/go/src/step8_macros/step8_macros.go
@@ -55,8 +55,8 @@ func is_macro_call(ast MalType, env EnvType) bool {
     if List_Q(ast) {
         slc, _ := GetSlice(ast)
         a0 := slc[0]
-        if Symbol_Q(a0) && env.Find(a0.(Symbol).Val) != nil {
-            mac, e := env.Get(a0.(Symbol).Val)
+        if Symbol_Q(a0) && env.Find(a0.(Symbol)) != nil {
+            mac, e := env.Get(a0.(Symbol))
             if e != nil { return false }
             if MalFunc_Q(mac) {
                 return mac.(MalFunc).GetMacro()
@@ -72,7 +72,7 @@ func macroexpand(ast MalType, env EnvType)  (MalType, error) {
     for ; is_macro_call(ast, env) ; {
         slc, _ := GetSlice(ast)
         a0 := slc[0]
-        mac, e = env.Get(a0.(Symbol).Val); if e != nil { return nil, e }
+        mac, e = env.Get(a0.(Symbol)); if e != nil { return nil, e }
         fn := mac.(MalFunc)
         ast, e = Apply(fn, slc[1:]); if e != nil { return nil, e }
     }
@@ -82,7 +82,7 @@ func macroexpand(ast MalType, env EnvType)  (MalType, error) {
 func eval_ast(ast MalType, env EnvType) (MalType, error) {
     //fmt.Printf("eval_ast: %#v\n", ast)
     if Symbol_Q(ast) {
-        return env.Get(ast.(Symbol).Val)
+        return env.Get(ast.(Symbol))
     } else if List_Q(ast) {
         lst := []MalType{}
         for _, a := range ast.(List).Val {
@@ -148,7 +148,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
     case "def!":
         res, e := EVAL(a2, env)
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, res), nil
+        return env.Set(a1.(Symbol), res), nil
     case "let*":
         let_env, e := NewEnv(env, nil, nil)
         if e != nil { return nil, e }
@@ -160,7 +160,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
             }
             exp, e := EVAL(arr1[i+1], let_env)
             if e != nil { return nil, e }
-            let_env.Set(arr1[i].(Symbol).Val, exp)
+            let_env.Set(arr1[i].(Symbol), exp)
         }
         ast = a2
         env = let_env
@@ -172,7 +172,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
         fn, e := EVAL(a2, env)
         fn = fn.(MalFunc).SetMacro()
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, fn), nil
+        return env.Set(a1.(Symbol), fn), nil
     case "macroexpand":
         return macroexpand(a1, env)
     case "do":
@@ -237,11 +237,11 @@ func rep(str string) (MalType, error) {
 func main() {
     // core.go: defined using go
     for k, v := range core.NS {
-        repl_env.Set(k, Func{v.(func([]MalType)(MalType,error)),nil})
+        repl_env.Set(Symbol{k}, Func{v.(func([]MalType)(MalType,error)),nil})
     }
-    repl_env.Set("eval", Func{func(a []MalType) (MalType, error) {
+    repl_env.Set(Symbol{"eval"}, Func{func(a []MalType) (MalType, error) {
         return EVAL(a[0], repl_env) },nil})
-    repl_env.Set("*ARGV*", List{})
+    repl_env.Set(Symbol{"*ARGV*"}, List{})
 
     // core.mal: defined using the language itself
     rep("(def! not (fn* (a) (if a false true)))")
@@ -255,7 +255,7 @@ func main() {
         for _,a := range os.Args[2:] {
             args = append(args, a)
         }
-        repl_env.Set("*ARGV*", List{args,nil})
+        repl_env.Set(Symbol{"*ARGV*"}, List{args,nil})
         if _,e := rep("(load-file \"" + os.Args[1] + "\")"); e != nil {
             fmt.Printf("Error: %v\n", e)
             os.Exit(1)
diff --git a/go/src/step9_try/step9_try.go b/go/src/step9_try/step9_try.go
index 322ee36..18f3c9c 100644
--- a/go/src/step9_try/step9_try.go
+++ b/go/src/step9_try/step9_try.go
@@ -55,8 +55,8 @@ func is_macro_call(ast MalType, env EnvType) bool {
     if List_Q(ast) {
         slc, _ := GetSlice(ast)
         a0 := slc[0]
-        if Symbol_Q(a0) && env.Find(a0.(Symbol).Val) != nil {
-            mac, e := env.Get(a0.(Symbol).Val)
+        if Symbol_Q(a0) && env.Find(a0.(Symbol)) != nil {
+            mac, e := env.Get(a0.(Symbol))
             if e != nil { return false }
             if MalFunc_Q(mac) {
                 return mac.(MalFunc).GetMacro()
@@ -72,7 +72,7 @@ func macroexpand(ast MalType, env EnvType)  (MalType, error) {
     for ; is_macro_call(ast, env) ; {
         slc, _ := GetSlice(ast)
         a0 := slc[0]
-        mac, e = env.Get(a0.(Symbol).Val); if e != nil { return nil, e }
+        mac, e = env.Get(a0.(Symbol)); if e != nil { return nil, e }
         fn := mac.(MalFunc)
         ast, e = Apply(fn, slc[1:]); if e != nil { return nil, e }
     }
@@ -82,7 +82,7 @@ func macroexpand(ast MalType, env EnvType)  (MalType, error) {
 func eval_ast(ast MalType, env EnvType) (MalType, error) {
     //fmt.Printf("eval_ast: %#v\n", ast)
     if Symbol_Q(ast) {
-        return env.Get(ast.(Symbol).Val)
+        return env.Get(ast.(Symbol))
     } else if List_Q(ast) {
         lst := []MalType{}
         for _, a := range ast.(List).Val {
@@ -148,7 +148,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
     case "def!":
         res, e := EVAL(a2, env)
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, res), nil
+        return env.Set(a1.(Symbol), res), nil
     case "let*":
         let_env, e := NewEnv(env, nil, nil)
         if e != nil { return nil, e }
@@ -160,7 +160,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
             }
             exp, e := EVAL(arr1[i+1], let_env)
             if e != nil { return nil, e }
-            let_env.Set(arr1[i].(Symbol).Val, exp)
+            let_env.Set(arr1[i].(Symbol), exp)
         }
         ast = a2
         env = let_env
@@ -172,7 +172,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
         fn, e := EVAL(a2, env)
         fn = fn.(MalFunc).SetMacro()
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, fn), nil
+        return env.Set(a1.(Symbol), fn), nil
     case "macroexpand":
         return macroexpand(a1, env)
     case "try*":        
@@ -259,14 +259,13 @@ func rep(str string) (MalType, error) {
 func main() {
     // core.go: defined using go
     for k, v := range core.NS {
-        repl_env.Set(k, Func{v.(func([]MalType)(MalType,error)),nil})
+        repl_env.Set(Symbol{k}, Func{v.(func([]MalType)(MalType,error)),nil})
     }
-    repl_env.Set("eval", Func{func(a []MalType) (MalType, error) {
+    repl_env.Set(Symbol{"eval"}, Func{func(a []MalType) (MalType, error) {
         return EVAL(a[0], repl_env) },nil})
-    repl_env.Set("*ARGV*", List{})
+    repl_env.Set(Symbol{"*ARGV*"}, List{})
 
     // core.mal: defined using the language itself
-    rep("(def! *host-language* \"go\")")
     rep("(def! not (fn* (a) (if a false true)))")
     rep("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))")
     rep("(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw \"odd number of forms to cond\")) (cons 'cond (rest (rest xs)))))))")
@@ -278,7 +277,7 @@ func main() {
         for _,a := range os.Args[2:] {
             args = append(args, a)
         }
-        repl_env.Set("*ARGV*", List{args,nil})
+        repl_env.Set(Symbol{"*ARGV*"}, List{args,nil})
         if _,e := rep("(load-file \"" + os.Args[1] + "\")"); e != nil {
             fmt.Printf("Error: %v\n", e)
             os.Exit(1)
@@ -287,7 +286,6 @@ func main() {
     }
 
     // repl loop
-    rep("(println (str \"Mal [\" *host-language* \"]\"))")
     for {
         text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
diff --git a/go/src/stepA_interop/stepA_interop.go b/go/src/stepA_interop/stepA_interop.go
index 322ee36..808022a 100644
--- a/go/src/stepA_interop/stepA_interop.go
+++ b/go/src/stepA_interop/stepA_interop.go
@@ -55,8 +55,8 @@ func is_macro_call(ast MalType, env EnvType) bool {
     if List_Q(ast) {
         slc, _ := GetSlice(ast)
         a0 := slc[0]
-        if Symbol_Q(a0) && env.Find(a0.(Symbol).Val) != nil {
-            mac, e := env.Get(a0.(Symbol).Val)
+        if Symbol_Q(a0) && env.Find(a0.(Symbol)) != nil {
+            mac, e := env.Get(a0.(Symbol))
             if e != nil { return false }
             if MalFunc_Q(mac) {
                 return mac.(MalFunc).GetMacro()
@@ -72,7 +72,7 @@ func macroexpand(ast MalType, env EnvType)  (MalType, error) {
     for ; is_macro_call(ast, env) ; {
         slc, _ := GetSlice(ast)
         a0 := slc[0]
-        mac, e = env.Get(a0.(Symbol).Val); if e != nil { return nil, e }
+        mac, e = env.Get(a0.(Symbol)); if e != nil { return nil, e }
         fn := mac.(MalFunc)
         ast, e = Apply(fn, slc[1:]); if e != nil { return nil, e }
     }
@@ -82,7 +82,7 @@ func macroexpand(ast MalType, env EnvType)  (MalType, error) {
 func eval_ast(ast MalType, env EnvType) (MalType, error) {
     //fmt.Printf("eval_ast: %#v\n", ast)
     if Symbol_Q(ast) {
-        return env.Get(ast.(Symbol).Val)
+        return env.Get(ast.(Symbol))
     } else if List_Q(ast) {
         lst := []MalType{}
         for _, a := range ast.(List).Val {
@@ -148,7 +148,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
     case "def!":
         res, e := EVAL(a2, env)
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, res), nil
+        return env.Set(a1.(Symbol), res), nil
     case "let*":
         let_env, e := NewEnv(env, nil, nil)
         if e != nil { return nil, e }
@@ -160,7 +160,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
             }
             exp, e := EVAL(arr1[i+1], let_env)
             if e != nil { return nil, e }
-            let_env.Set(arr1[i].(Symbol).Val, exp)
+            let_env.Set(arr1[i].(Symbol), exp)
         }
         ast = a2
         env = let_env
@@ -172,7 +172,7 @@ func EVAL(ast MalType, env EnvType) (MalType, error) {
         fn, e := EVAL(a2, env)
         fn = fn.(MalFunc).SetMacro()
         if e != nil { return nil, e }
-        return env.Set(a1.(Symbol).Val, fn), nil
+        return env.Set(a1.(Symbol), fn), nil
     case "macroexpand":
         return macroexpand(a1, env)
     case "try*":        
@@ -259,11 +259,11 @@ func rep(str string) (MalType, error) {
 func main() {
     // core.go: defined using go
     for k, v := range core.NS {
-        repl_env.Set(k, Func{v.(func([]MalType)(MalType,error)),nil})
+        repl_env.Set(Symbol{k}, Func{v.(func([]MalType)(MalType,error)),nil})
     }
-    repl_env.Set("eval", Func{func(a []MalType) (MalType, error) {
+    repl_env.Set(Symbol{"eval"}, Func{func(a []MalType) (MalType, error) {
         return EVAL(a[0], repl_env) },nil})
-    repl_env.Set("*ARGV*", List{})
+    repl_env.Set(Symbol{"*ARGV*"}, List{})
 
     // core.mal: defined using the language itself
     rep("(def! *host-language* \"go\")")
@@ -278,7 +278,7 @@ func main() {
         for _,a := range os.Args[2:] {
             args = append(args, a)
         }
-        repl_env.Set("*ARGV*", List{args,nil})
+        repl_env.Set(Symbol{"*ARGV*"}, List{args,nil})
         if _,e := rep("(load-file \"" + os.Args[1] + "\")"); e != nil {
             fmt.Printf("Error: %v\n", e)
             os.Exit(1)
diff --git a/go/src/types/types.go b/go/src/types/types.go
index 613bfb5..54e4176 100644
--- a/go/src/types/types.go
+++ b/go/src/types/types.go
@@ -4,6 +4,7 @@ import (
     "reflect"
     "errors"
     "fmt"
+    "strings"
 )
 
 // Errors/Exceptions
@@ -21,10 +22,9 @@ type MalType interface {
 }
 
 type EnvType interface {
-    //Find(key string) *EnvType
-    Find(key string) EnvType
-    Set(key string, value MalType) MalType
-    Get(key string) (MalType, error)
+    Find(key Symbol) EnvType
+    Set(key Symbol, value MalType) MalType
+    Get(key Symbol) (MalType, error)
 }
 
 // Scalars
@@ -57,6 +57,20 @@ func Symbol_Q(obj MalType) bool {
 }
 
 
+// Keywords
+func NewKeyword(s string) (MalType, error) {
+    return "\u029e" + s, nil;
+}
+
+func Keyword_Q(obj MalType) bool {
+    if obj == nil { return false }
+    switch s := obj.(type) {
+    case string: return strings.HasPrefix(s, "\u029e")
+    default: return false
+    }
+}
+
+
 // Strings
 func String_Q(obj MalType) bool {
     if obj == nil { return false }