PythonやRubyだとあんな感じで書くけど、CoffeeScriptだとどうかなーというのを思い浮かぶがままに書き下していく。
- JavaScriptも追加
コメント
# comment
# comment
// comment
# comment
複数行にまたがるコメント
Pythonには複数行コメントがないので文字列で代用する
'''
comment
'''
"""
comment
"""
=begin
comment
=end
/*
comment
*/
###
comment
###
文字の埋め込み
>>> width = 100
>>> "{0}px".format(width)
"100px"
>>> "%dpx" % width
"100px"
width = 100
p "#{width}px"
# => 100px
width = 100;
console.log("" + width + "px");
Rubyに似てる
width = 100
console.log "#{width}px"
# 100px
複数行にまたがる文字列
>>> a = '''a
... b'''
"a\nb"
a = 'a
b'
# => "a\nb"
a = 'a\
b';
// "a\n b"
a = 'a
b'
# "ab"
連想配列
d = {'a': 0, 'b': 2}
d = {:a => 0, :b => 2}
d = {a: 0, b: 2}
d = a: 0, b: 2
d = {a: 0, b: 2} # もOK
# 複数行にまたがる場合は`,`を省略可
d =
a: 0 # 途中にコメントも入れられる
b: 2
d = {
a: 0
b: 2
}
配列
l = [1, 3, 5]
l = [1, 3, 5]
l = [1, 3, 5]
l = [1, 3, 5]
#複数行にまたがる場合は`,`が省略可
l = [
1
3
5
]
連続した配列
>>> range(5)
[0, 1, 2, 3, 4]
>>> range(5, 0, -1)
[5, 4, 3, 2, 1]
>>> range(2, 5)
[2, 3, 4]
[0...5]
# [0, 1, 2, 3, 4]
[0..4]
# [0, 1, 2, 3, 4]
[4...-1]
# [4, 3, 2, 1, 0]
[4..0]
# [4, 3, 2, 1, 0]
[2...5]
# [2, 3, 4]
[2..4]
# [2, 3, 4]
配列へのアクセス
>>> l = range(10)
>>> l[1]
1
>>> l[2:4]
[2, 3]
>>> l[2:]
[2, 3, 4, 5, 6, 7, 8, 9]
>>> l[:4]
[0, 1, 2, 3]
>>> l[::3]
[0, 3, 6, 9]
>>> l[-1]
9
>>> l[3:6] = [6, 8, 9]
>>> l
[0, 1, 2, 6, 8, 9, 6, 7, 8, 9]
l = [0...10]
l[1]
# 1
l[2...4]
# [2, 3]
l[2...]
# [2, 3, 4, 5, 6, 7, 8, 9]
l[...4]
# [0, 1, 2, 3]
i for i in l by 3
# [0, 3, 6, 9]
l[l.length-1]]
# 9
l[3...6] = [6, 8, 9]
# [0, 1, 2, 6, 8, 9, 6, 7, 8, 9]
リスト内包表記
単純な場合
>>> l = ['a', 'b', 'c']
>>> [v for v in l]
['a', 'b', 'c']
>>> [(i, v) for i, v in enumerate(l)]
[(0, 'a'), (1, 'b'), (2, 'c')]
>>> d = {'a': 0, 'b': 1, 'c': 2}
>>> [k for k in d]
['a', 'b', 'c']
>>> [(k, v) for k, v in d.items()]
[('a', 0), ('b', 1), ('c', 2)]
l = ['a', 'b', 'c']
v for v in l
# ['a', 'b', 'c']
[v for v in l]
# [ ['a', 'b', 'c'] ]
[i, v] for i, v in l
# [[0, 'a'], [1, 'b'], [2, 'c']]
d = a: 0, b: 1, c: 2
k for k of d
# ['a', 'b', 'c']
[k, v] for k, v of d
# [['a', 0], ['b', 1], ['c', 2]]
リスト内包表記を使ったフィルタリング
>>> [i for i in range(10) if i % 3 == 0]
[0, 3, 6, 9]
i for i in [0...10] when i % 3 is 0
# [0, 3, 6, 9]
CoffeeScriptのリスト内包表記はもっといろいろできる
>>> for i in range(5)
... print i
0
1
2
3
4
console.log i for i in [0...5]
# 0
# 1
# 2
# 3
# 4
関数
def func(arg, *args):
pass
def func(arg, *args)
end
var func = function(arg) {
var args = 2 <= arguments.length ? Array.prototype.slice.call(arguments, 1) : []
}
func = (arg, args...) ->
関数呼び出し
Pythonは関数呼び出しに()が必須
>>> def foo(): return 'foo'
>>> foo
<function __main.foo>
>>> foo()
'foo'
Rubyは不要
def foo
'foo'
end
p foo
# => foo
def bar(x)
x
end
p bar 'bar'
# => bar
JavaScriptはインスタンス生成時は不要。普通の呼び出し時は必須
var foo = function() {return 'foo'};
console.log(typeof foo);
// 'function'
console.log(foo());
// 'foo'
f = new foo;
console.log(f.construoctor === foo);
// true
CoffeeScriptは引数が渡されない場合は()が必要、引数ありの場合は不要
foo = -> 'foo'
console.log typeof foo
# 'function'
console.log foo()
# foo
bar = (x) -> x
console.log foo 'bar'
# bar
関数の戻り値
PythonとJavaScriptはreturn必須。無ければPythonならNoneが、JavaScriptならundefinedが返る。
>>> def bar(): 'bar'
>>> bar() is None
True
var bar = function() { 'bar' };
console.log(bar === undefined);
// true
RubyとCoffeeScriptは最後の文がreturnされる。
def bar
'bar'
end
bar
# => 'bar'
bar = -> 'bar'
bar()
# 'bar'
クラス
>>> class Klass(object):
... def __init__(self, name):
... self.name = name
>>> k = Klass('hoge')
>>> k.name
"hoge"
class Klass
attr "name"
def initialize(name)
@name = name
end
end
k = Klass.new 'hoge'
p k.name
# => hoge
function Klass(name) {
this.name = name;
}
var k = new Klass('hoge');
console.log(k.name);
// hoge
class Klass
constructor: (name) ->
@name = name
k = new Klass 'hoge'
console.log k.name
# hoge
継承
>>> class Parent(object):
... def foo(self):
... print 'parent'
>>> class Child(Parent):
... def foo(self):
... super(Child, self).foo()
... print 'child'
>>> c = Child()
>>> c.foo()
parent
child
class Parent
def foo
p 'parent'
end
end
class Child < Parent
def foo
super
p 'child'
end
end
c = Child.new
c.foo
# => parent
# => child
function Parent() {}
Parent.prototype.foo = function () { console.log('parent'); };
function Child() {}
Child.prototype = new Parent;
Child.prototype.foo = function () {
Parent.prototype.foo.call(this);
console.log('child');
}
var c = new Child;
c.foo();
// parent
// child
class Parent
foo: ->
console.log 'parent'
class Child extend
foo: ->
super
console.log 'child'
c = new Child
c.foo()
# parent
# child
Mixin
module Fooable
def foo
p 'foo'
end
end
class Klass
include Fooable
end
k = Klass.new
k.foo
# => 'foo
# https://gist.github.com/993415
class Mixin
augment: (t) ->
(t[n] = m unless n == 'augment' or !this[n].prototype?) for n, m of this
class Fooable extends Mixin
foo: ->
console.log 'foo'
class Klass
constructor: ->
Fooable::augment @
k = new Klass
k.foo()
# foo