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65 points surprisetalk | 1 comments | 27 Aug 25 13:51 UTC | HN request time: 0.203s | source

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layer8 ◴[30 Aug 25 19:59 UTC] No.45077545[source]▶

> Note the difference between "where" and "such that". "Where" is used when the preceding notation is being defined; "such that" is used when it is already defined and its value is being restricted.

I found this interesting. SQL and Swift use “where” for restrictions. Any other examples in programming languages?

If a programming language wanted to use a keyword for restrictions that isn’t “where” (and still is a single word, hence “such that” doesn’t qualify), what word would be suitable instead? “With”? “Having”?

replies(3): >>45077717 #>>45078657 #>>45089150 #

1. gizmo686 ◴[01 Sep 25 03:20 UTC] No.45089150[source]▶

>>45077545 #

Haskell uses where in the sense the article describes.

E.g

   f x = y + 1
     where y = 2 * x

Haskell also has a "let" notation

    f x = let y = 2 * x
      in y + 1

> If a programming language wanted to use a keyword for restrictions that isn’t “where” (and still is a single word, hence “such that” doesn’t qualify), what word would be suitable instead? “With”? “Having”?

If? Python does so with it's list comprehensions:

  [ x for x in range(100) if x % 2 == 0 ]

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