Go: add missing env.go

1 files changed, 59 insertions, 0 deletions

diff --git a/go/src/env/env.go b/go/src/env/env.go
new file mode 100644
index 0000000..4d20857
--- /dev/null
+++ b/go/src/env/env.go
@@ -0,0 +1,59 @@
+package env
+
+import (
+    "errors"
+    //"fmt"
+)
+
+import (
+    . "types"
+)
+
+type Env struct {
+    data map[string]MalType
+    outer EnvType
+}
+
+func NewEnv(outer EnvType, binds_mt MalType, exprs_mt MalType) (EnvType, error) {
+    env := Env{map[string]MalType{}, outer}
+
+    if binds_mt != nil && exprs_mt != nil {
+        binds, e := GetSlice(binds_mt); if e != nil { return nil, e }
+        exprs, e := GetSlice(exprs_mt); if e != nil { return nil, e }
+        // Return a new Env with symbols in binds boudn to
+        // corresponding values in exprs
+        for i := 0; i < len(binds); i+=1 {
+            if (Symbol_Q(binds[i]) && binds[i].(Symbol).Val == "&") {
+                env.data[binds[i+1].(Symbol).Val] = List{exprs[i:],nil}
+                break
+            } else {
+                env.data[binds[i].(Symbol).Val] = exprs[i]
+            }
+        }
+    }
+    //return &et, nil
+    return env, nil
+}
+
+func (e Env) Find(key string) EnvType {
+    if _, ok := e.data[key]; ok {
+        return e
+    } else if (e.outer != nil) {
+        return e.outer.Find(key)
+    } else {
+        return nil
+    }
+}
+
+func (e Env) Set(key string, value MalType) MalType {
+    e.data[key] = value
+    return value
+}
+
+func (e Env) Get(key string) (MalType, error) {
+    env := e.Find(key)
+    if env == nil {
+        return nil, errors.New("'" + key + "' not found")
+    }
+    return env.(Env).data[key], nil
+}