layout: post title: 文摘 - Rob Pike的五條程式設計規則 categories: [dev, digest]
From: https://users.ece.utexas.edu/~adnan/pike.html
Rob Pike's 5 Rules of Programming
Rule 1. You can't tell where a program is going to spend its time. Bottlenecks occur in surprising places, so don't try to second guess and put in a speed hack until you've proven that's where the bottleneck is.
不要嘗試猜測效能瓶頸，過早進行效能最佳化，因為他們經常出現在意想不到的地方。
Rule 2. Measure. Don't tune for speed until you've measured, and even then don't unless one part of the code overwhelms the rest.
先測量速度。再開始最佳化。
Rule 3. Fancy algorithms are slow when n is small, and n is usually small. Fancy algorithms have big constants. Until you know that n is frequently going to be big, don't get fancy. (Even if n does get big, use Rule 2 first.)
當發現n足夠大，才改用更精巧的演算法。
Rule 4. Fancy algorithms are buggier than simple ones, and they're much harder to implement. Use simple algorithms as well as simple data structures.
盡可能地使用簡單的演算法和資料結構。
Rule 5. Data dominates. If you've chosen the right data structures and organized things well, the algorithms will almost always be self-evident. Data structures, not algorithms, are central to programming.
選擇正確的資料結構才是重點。
我認為這邊的精神其實是「盡量推遲無法逆轉的決策」。進行效能最佳化以後會增加程式碼閱讀理解的難度，後面要再修改也就更加困難。使用更精巧的演算法也是相同的道理。因此在開發時盡量的保持簡單易懂是很重要的。
這也很好的體現在Go語言上。首先它內建的資料結構只有array (slice)和map (hash table)。然而這兩種資料結構就可以實作絕大部分的程式。只有非常少的部分需要引入如stack、heap、queue...等等。而且使用這些資料結構也僅是加快速度，在程式的正確性上是沒有差別的。另外也可以從Go語言的語法簡潔性看出，整體的設計哲學就是希望他保持簡單。