upvote

points

by Heliodex18 hours ago |
comments
upvoteby noelwelsh12 hours ago|
next
[-]
Exactly. I don't understand why people think the ternary operator is needed when you can just make `if` an expression instead of a statement. Then there is no new syntax to learn and `if` just becomes more useful.
reply
upvoteby aeonflux5 hours ago|
parent|
[-]
I don't really understand where is this need to compress the logic into where small chunks comes from. In result we get single line of code which has multiple statement conditions, different paths, and it's not possible to grasp in one go.

Other practical example why ternary is bad: Many code-coverage solutions break on ternary because they don't correctly see that one of the branches was missed in tests.

reply
upvoteby bruce3434343 hours ago|
parent|
[-]
Because you can deduplicate certain parts of the logic which make the whole thing less error prone, such as

    if c
      x=1
    else
      x=2
If I ever want to change x, or refactor this code some other way, its a more brittle process over x=c?1:2

The ternary expression also takes up much less space so there is less of an emphasis on it, this can be a stylistic tool in a programmer's toolbox

reply
upvoteby drunken_thor5 hours ago|
prev|
next
[-]
I think that allowing an if statement to return a value to deal with the ternary introduces a now concept to Lua and that is that the value on the final line of a block is a return value much like Ruby. This changes the logic of the entire language more than adding a ternary. I do prefer the if statement as it allows so much more emergent behaviour, but it does have more implications to consider.
reply
upvoteby Heliodex3 hours ago|
parent|
[-]
I suppose, though I feel what most people in this thread are thinking of is updating the existing if statement to also work as an expression, which does have plenty of implications (not that I think they would be bad, just more of a change to the language than the feature designers were going for) including final returns. The example I took from Luau still keeps the if statement and the if-then-else expression as separate constructs. One problem is that the statement and expression versions look very similar despite having different semantics (expression version must only contain expressions in its branches, must have an `else` case, does not have `end`).

Of course there are differences between LuaJIT and Luau that I think influence their decisions on possible ternary expression features:

- Luau users are disproportionately beginners to programming that I believe would find the if-then-else expression syntax easier to learn; LuaJIT developers have a larger user base of professional devs wanting to make their code faster, and they will probably be more familiar with the `x ? y : z` style since it's used in plenty of other languages.

- Luau is a lot faster moving in its development than LuaJIT in terms of language features, the Luau team just wanted to move people to ternaries from `x and y or z` because it's easier to optimise in a normal interpreter; LuaJIT, with their JIT, I assume would be able to more easily implement optimisations for constructs like `x and y or z` despite its slight semantic differences (my assumption on why the change is being considered now rather than earlier).

reply
upvoteby mjcohen18 hours ago|
prev|
[-]
The ternary operator is easy to nest if you put each clause on a separate line. Then it looks just like nested if-then-else.
reply
upvoteby edoceo17 hours ago|
parent|
next
[-]
I love the ternary operator as much as anyone. But dang if it doesn't get hard to read when there is are a few, nested even.

Does that operator compile to faster assembly that if I make the same logic with verbose `if` logic? Is that a language specific outcome?

reply
upvoteby gnubison17 hours ago|
parent|
[-]

    cond1 ? res1 :
    cond2 ? res2 :
    cond3 ? res3 :
    or_else_res
If they are truly nested, then that is confusing. But if you have an if-else chain, then it can be quite readable.
reply
upvoteby a-french-anon12 hours ago|
parent|
next
[-]
Or they could just ask granddaddy for advice:

  (cond (cond1 res1)
        (cond2 res2)
        (cond3 res3)
        (t     else_res))
=)
reply
upvoteby matheusmoreira1 hours ago|
parent|
[-]
An elegant weapon, for a more civilized age...
reply
upvoteby froh6 hours ago|
parent|
prev|
next
[-]
or

  if cond1 then res1
  else if cond2 then res2
  else if cond3 then res3
  else or_else_res
or

  if cond1 then res1
  elif cond2 then res2
  elif cond3 then res3
  else or_else_res
what is most lua-like?
reply
upvoteby shevy-java16 hours ago|
parent|
prev|
[-]
I find that so much harder to read compared to if/else or case/when in ruby.

The ? is basically an attempt to use fewer if/else, at the cost of condensed if-else like structure. I always need to look at both parts after the ? whereas in a single if or elsif I don't. case/when in ruby is even better here e. g. regex check:

   def foo(i)
     case i
     when /^cat/
       handle_cats
     when /^dog/
       handle_dogs
(I ommitted the "end"s here to just focus on the conditional logic.)
reply