restructure project

internal/object/environment.go

@@ -0,0 +1,47 @@
+package object
+
+import "unicode"
+
+func NewEnclosedEnvironment(outer *Environment) *Environment {
+	env := NewEnvironment()
+	env.outer = outer
+	return env
+}
+
+func NewEnvironment() *Environment {
+	s := make(map[string]Object)
+	return &Environment{store: s, outer: nil}
+}
+
+type Environment struct {
+	store map[string]Object
+	outer *Environment
+}
+
+func (e *Environment) Get(name string) (Object, bool) {
+	obj, ok := e.store[name]
+	if !ok && e.outer != nil {
+		obj, ok = e.outer.Get(name)
+	}
+	return obj, ok
+}
+
+func (e *Environment) Set(name string, val Object) Object {
+	e.store[name] = val
+	return val
+}
+
+// ExportedHash returns a new Hash with the names and values of every publicly
+// exported binding in the environment. That is every binding that starts with a
+// capital letter. This is used by the module import system to wrap up the
+// evaluated module into an object.
+func (e *Environment) ExportedHash() *Hash {
+	pairs := make(map[HashKey]HashPair)
+	for k, v := range e.store {
+		if unicode.IsUpper(rune(k[0])) {
+			s := &String{Value: k}
+			pairs[s.HashKey()] = HashPair{Key: s, Value: v}
+		}
+	}
+	return &Hash{Pairs: pairs}
+}