IT討論區(214) - 做中資慘過做奴隸……

我認知中呢種optimization都唔識做既一定唔係合格商業compiler
C++又好Java又好, 最後既machine code / byte code一定係一樣

Premature optimization is the root of all evil
opt code length, opt performance, opt algo都係
compiler同language咁多年嚟加咗咁多opt野就係為咗減輕dev負擔，你又走番去同佢搶飯食
大多數code根本唔需要opt呢個level，諗下點樣寫clean code同快手搞掂個project先啦
code夠clean compiler 就多數識做野

短!=clean，為咗短而塞一堆花臣自己都睇得辛苦，compiler同其他人點幫你
諗下自己段code有冇哂時間做多餘野，畀啲空間自己寫開啲

真係要opt先唔同講法，十行clean code變幾百行code很正常

尤其Java之類既high level lang, 你hint compiler應該反而係為左叫compiler唔好opt某D野 rather than 幫佢opt.
我意思係prefix定postfix係個人/team prefer而唔係compiler concern

readability>>>>>optimization
如果寫啲code係重視performance到要forgo readability嘅話
寫嗰個應該已經有足夠經驗唔會鑽呢種牛角尖

tail recursion係language feature，by design善用佢唔影響readability，甚至唔識嘅人根本唔會意識到有opt，呢種opt當本能算啦

更正: In c++, tail recursion係非正式language feature, 只係主流compiler都support

用完obscure opt，冇隊友睇得明驚一改就炒，咁你就多一條洗唔走嘅debt，走咗都有人煩

問水幾時食川菜

快

bugbug食辣成癮

原來同tail recur同期學嘅copy elision, rvo都唔係正式lang feature，只係standard allow... 定位好ambiguous

一半半, 某D optimization你未必sure compiler會一定會幫你做, 但同時有D optimization唔做根本就唔算一個正經compiler.
例如你有個function有行int secondsPerDay = 24 * 60 * 60;, 正常你唔會擔心每次call個function都會重新計一次secondsPerDay.
就算tail recursion, 如果一隻FP lang compiler唔識做, 佢根本就唔係合格既compiler.