Coding Style – Why Are ‘If Elif Else’ Statements Virtually Never in Table Format?

coding-style

if   i>0 : return sqrt(i)  
elif i==0: return 0  
else     : return 1j * sqrt(-i)

VS

if i>0:  
   return sqrt(i)  
elif i==0:  
   return 0  
else:  
   return 1j * sqrt(-i)

Given the above examples, I don't understand why I virtually never see the first style in code bases. To me, you turn the code into a tabular format that shows clearly what you want. First column can virtually be ignored. Second column identifies the condition and the third column gives you the output you want. It seems, at least to me, straight-forward and easy to read. Yet I always see this simple kind of case/switch situation come out in the extended, tab indented format. Why is that? Do people find the second format more readable?

The only case where this could be problematic is if the code changes and gets longer. In that case, I think it's perfectly reasonable to refactor the code into the long, indented format. Does everyone do it the second way simply because it's the way it always was done? Being a devil's advocate, I guess another reason might be because people find two different formats depending upon complexity of the if/else statements to be confusing? Any insight would be appreciated.

Best Answer

One reason may be that you're not using languages where it's popular.

A few counter-examples:

Haskell with guards and with patterns:

sign x |  x >  0        =   1
       |  x == 0        =   0
       |  x <  0        =  -1

take  0     _           =  []
take  _     []          =  []
take  n     (x:xs)      =  x : take (n-1) xs

Erlang with patterns:

insert(X,Set) ->
    case lists:member(X,Set) of
        true  -> Set;
        false -> [X|Set]
    end.

Emacs lisp:

(pcase (get-return-code x)
  (`success       (message "Done!"))
  (`would-block   (message "Sorry, can't do it now"))
  (`read-only     (message "The shmliblick is read-only"))
  (`access-denied (message "You do not have the needed rights"))
  (code           (message "Unknown return code %S" code)))

Generally I see the table format is pretty popular with functional languages (and in general expression based ones), while breaking the lines is most popular in others (mostly statement based).

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