Comment by ze7111 | Hacker News Reader

Comment by ze7111 | Hacker News Reader

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Hey, I'm one of the dev's; We thought about this ALOT like 4 hour long arguments, we asked a lot of our friends and its was really mixed, some people hated the python style ternary, others loved it, we weren't sure what to choose but the numbers were 38.5% for `<expr> if <cond> else <expr>, 27.25% for `<cond> ? <expr> : <expr>`, and 34.25% for `if <cond> { <expr> } else { <expr }` we did also look at a few other styles like: `if <cond>: <expr> else: <expr>`, but we decided that the python style is the best for a simple reason, its easier for new dev's who want to come into systems programing or writing low level code. If a lot of people do really hate it, we can swap it out before an alpha it would be a really simple AST node parser change...

I don't know if your language is expression based like Rust, but in Rust the nice thing is that it's just the regular if syntax being used as an expression and not some additional special case syntax, which is elegant.

I actually like the Haskell syntax more because it's looks nicer when formatted in multiple lines:

  -- Haskell:
  -- single line
  if ... then ... else ...

  -- multiline
  if ...
      then ...
      else ...

Where in Rust with normal formatting it because 5 whole lines:

  // Rust:
  let result = if ... {
      ...
  } else {
      ...
  };

  // or, 4 lines but less common:
  let result = match ... {
      true => ...,
      false => ...,
  };

I think the strongest argument for condition-first that's unrelated to "taste" is the fact it is consistent with the order of execution:

  # Python:
  # you have to read "from the middle out" to read with the order of execution
  x = a() if b() else c()

I also strongly suggest you look up why Python ended up with the syntax it did. The reasons were not really good and not really applicable to a new language. Maybe my memory is bad because I can't find the source, but I remember one of the justifications was simply that it turned out faster in cpython (the python interpreter) in the test implementation they did.

I might also consider asking Chris Lattner (Mojo language). They did use that syntax in Mojo, because it is made to be a superset of Python. But I remember hearing him say he really disliked it.

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