概要
Proc/lambdaとcallとcase
詳細
Proc/lambdaは通常呼び出し方には様々な形式があります。
self[*arg] -> ()[permalink][rdoc] call(*arg) -> () self === *arg -> () yield(*arg) -> ()
「===」はcase whenを利用する際を想定して用意されています。
Proc/lambdaの様々な呼び出し方
サンプルコード
require 'tbpgr_utils' increment1 = lambda{|a|a + 1} increment2 = -> (a) {a + 1} [*1..3].each do |v| bulk_puts_eval binding, <<-EOS v increment1.call v increment2.call v increment1 === v increment2 === v increment1.(v) increment1.(v) increment2.(v) increment1[v] increment2[v] increment1.yield v increment2.yield v EOS end __END__ 下記はTbpgrUtils gemの機能 bulk_puts_eval https://rubygems.org/gems/tbpgr_utils https://github.com/tbpgr/tbpgr_utils
出力
v # => 1 increment1.call v # => 2 increment2.call v # => 2 increment1 === v # => 2 increment2 === v # => 2 increment1.(v) # => 2 increment2.(v) # => 2 increment1[v] # => 2 increment2[v] # => 2 increment1.yield v # => 2 increment2.yield v # => 2 v # => 2 increment1.call v # => 3 increment2.call v # => 3 increment1 === v # => 3 increment2 === v # => 3 increment1.(v) # => 3 increment2.(v) # => 3 increment1[v] # => 3 increment2[v] # => 3 increment1.yield v # => 3 increment2.yield v # => 3 v # => 3 increment1.call v # => 4 increment2.call v # => 4 increment1 === v # => 4 increment2 === v # => 4 increment1.(v) # => 4 increment2.(v) # => 4 increment1[v] # => 4 increment2[v] # => 4 increment1.yield v # => 4 increment2.yield v # => 4
case when と lambda
サンプルコード
require 'tbpgr_utils' ret = [*1..30].reduce([]) do |r, v| case v when -> (x) {x % 15 == 0} r << "fizzbuzz" when -> (x) {x % 3 == 0} r << "fizz" when -> (x) {x % 3 == 0} r << "fizz" else r << v end r end.join(",") print ret __END__ 下記はTbpgrUtils gemの機能 bulk_puts_eval https://rubygems.org/gems/tbpgr_utils https://github.com/tbpgr/tbpgr_utils
出力
1,2,fizz,4,5,fizz,7,8,fizz,10,11,fizz,13,14,fizzbuzz,16,17,fizz,19,20,fizz,22,23,fizz,25,26,fizz,28,29,fizzbuzz
