Python入門
関数内関数（関数のネスト）とスコープ

def 外側の関数():
    def 内側の関数():
        内側の関数の処理
    ・・・
    内側の関数の呼び出し
    外側の関数の処理

def fn():
    return "Python def"
print(fn())

def fn_outer():
    def fn_inner():
        return "Python def"
    print(fn_inner())
fn_outer()

def fn():
    def fn_inner():
        print(s)
    s = "Enclosing scope"
    fn_inner()
fn()

def fn():
    def fn_inner():
        s = "write Enclosing"
        print(s)
    s = "Enclosing scope"
    fn_inner()
    print(s)
fn()

def fn():
    def fn_inner():
        print(s) #エンクロージング変数を参照
        s = "write Enclosing" #これはエラー
        print(s)
    s = "Enclosing scope"
    fn_inner()
    print(s)
fn()

def fn():
    def fn_inner():
        nonlocal s #ローカル変数ではない
        s = "write Enclosing"
        print(s)
    s = "Enclosing scope"
    fn_inner()
    print(s)
fn()

def fn():
    def fn_inner():
        print(s)
    fn_inner()
    print(s)
s = "Global scope"
fn()

def fn():
    s = "write Global"
    print(s)
s = "Global scope"
fn()
print(s)

def fn():
    print(s)
    s = "write Global"
    print(s)
s = "Global scope"
fn()
print(s)

def fn():
    global s #グローバル変数であると宣言
    s = "write Global"
    print(s)
s = "Global scope"
fn()
print(s)