Arc Forumnew | comments | leaders | submitlogin
2 points by eds 6122 days ago | link | parent

Yeah, I don't know what to do about that one. I've been thinking about it for a while, I just didn't know that was what you were asking.

I can't see any way to make indentation show you need just a symbol and not a function call with no arguments. You could add symbols, but that works against the removal of the parentheses in the first place.

Its a bit of a hack but if you had a simple read macro for an identity function you could do it. (Quote doesn't quite work because it prevents evaluation.) But say you had a function identity like such:

  (def identity (x) x)
And you defined a CL style read macro (e.g. $) to expand to (identity x). Then in my current function, because the read macro would expand before checking the subexpression to see if it was a list or not, you could do the following:

  if
    $test
      exp
        exp2
          very-long-exp3 5 6 7 8
        some-random-exp4
    $test2
      exp5
        exp6
          exp7
Which basically exchanges all the parentheses in the traditional version for a identity macro. Of course, it isn't exactly the same because you are adding extra meaning (the call to identity) to the expression. But maybe you could make it a macro instead of a function, and do the expansion at compile time (although this is dangerous because if you expanded the macro too soon you would defeat the purpose of using it in the first place...):

  (mac identity (x) x)
On the other hand you could alway just use traditional s-expressions in the middle of significant-indent code. The goal is to make parentheses optional, not to remove them entirely. Sometimes it may just be more convenient to leave them in than take them out.