[E-Lang] the return of `return'

[zooko@zooko.com]

Thanks, Darius, for this informative article!

My responses below are all questions and assertions about factual matters, not
about values.


 Darius Bacon <darius@accesscom.com> wrote:
>
> so the `return' doesn't return from the function a beginner would
> expect.  This could be fixed by giving `for' an uglier expansion.  Or,
> we could change the definition syntax to explicitly name the return
> escaper, like
> 
>    def foo(collection) return { 
>        for key => value in collection { ... return(x) ... }
>    }
...
> This preserves the security properties of Zooko's idea, at the cost of
> an unfamiliar definition syntax.  But familiarity was our main goal.


Couldn't it just be the innermost function that was declared with `def'?


> Third, if `return' is required then common E patterns are just too
> painful:
> 
>    def fooMaker(x) {
>        return(def foo {
>            to blat() { ... }
>        })
>    }
> 
> Some ideas on this one: 
> 
> 1. Make `return' optional.  Then the :retAny guard would be no help.


One of the reasons that I like the `:ret' guards is that they are optional.
The example you give above could just be:

   def fooMaker(x) :expAny {
   ...

or better yet:

   def fooMaker(x) :expSomeUsefulGuardHere {
   ...


> With all these unappealing alternatives, I have to wonder how shocking
> E's expression style really is for our users.  There are at least two
> popular expression-style languages: Perl and the sh family.


... and both have an optional `return' keyword which immediately exits from the
lexically innermost function with the optionally non-parenthesized accompanying
expression as the return value.


Regards,

Zooko