You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: for.go
    path of file: ./repos/gomacro/classic
    
    the code of the file until where you have to start completion: /*
 * gomacro - A Go interpreter with Lisp-like macros
 *
 * Copyright (C) 2017-2019 Massimiliano Ghilardi
 *
 *     This Source Code Form is subject to the terms of the Mozilla Public
 *     License, v. 2.0. If a copy of the MPL was not distributed with this
 *     file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 *
 * for.go
 *
 *  Created on: Feb 15, 2017
 *      Au
    
func (env *Env) evalForRange(node *ast.RangeStmt) (r.Value, []r.Value) {
	// Debugf("evalForRange() init = %#v, cond = %#v, post = %#v, body = %#v", node.Init, node.Cond, node.Post, node.Body)

	container := env.evalExpr1(node.X)
	if container == NilR || container == NoneR {
		return env.Errorf("invalid for range: cannot iterate on nil: %v evaluated to %v", node.X, container)
	}

	switch container.Kind() {
	case r.Chan:
		return env.evalForRangeChannel(container, node)
	case r.Map:
		return env.evalForRangeMap(container, node)
	case r.Slice, r.Array:
		return env.evalForRangeSlice(container, node)
	case r.String:
		// Golang specs https://golang.org/ref/spec#RangeClause
		// "For a string value, the "range" clause iterates over the Unicode code points in the string"
		return env.evalForRangeString(container.String(), node)
	case r.Ptr:
		if container.Elem().Kind() == r.Array {
			return env.evalForRangeSlice(container.Elem(), node)
		}
	}
	return env.Errorf("invalid for range: expecting array, channel, map, slice, string, or pointer to array, found: %v <%v>",
		container, typeOf(container))
}