Hi Tomas,
> I am inclined to think that fexprs are not a good thing, because like
> first class continuations, they break compose-ability (or whatever is
> the english word for that).
FEXPRs a not so very important. They just allow you to avoid having to
quote everything.
I don't understand all the fuss that is made about them. It is perhaps
because they are more powerful than the holy macros.
> That brings the question of how much of PicoLisp really needs fexprs? I
> think I could implement most of PicoLisp in Common Lisp rather easily
> using functions and macros without the need for fexprs at all. Even in
> case of PicoLisp, most of the things are actually not fexprs. It's just
> that everything is implemented using FEXPRs under the hood in PicoLisp.
Right. As I said above, they are mainly a cosmetic issue. But you have
to keep in mind that in typical PicoLisp code, almost *everything* runs
in a FEXPR. Take a simple HTML form like
(action
(html 0 "Form" "@lib.css" NIL
(<h2> NIL "Title")
(<div> 'cls
(form NIL
(gui '(+TextField) 10 "Text")
(gui '(+NumField) 10 "Number")
(gui '(+Button) "Action"
'(doSomething) ) ) ) ) )
All functions execpt 'gui' and 'doSomething' are FEXPRs here.
Without FEXPRS, this example would look like
(action
'(html 0 "Form" "@lib.css" NIL
'(<h2> NIL "Title")
'(<div> 'cls
'(form NIL
'(gui '(+TextField) 10 "Text")
'(gui '(+NumField) 10 "Number")
'(gui '(+Button) "Action"
''(doSomething) ) ) ) ) )
Not so much difference, but tedious and error-prone.
Macros make only sense if you compile the code, and the execute it many
times. This discourages such single-pass code like in the example above.
Cheers,
- Alex
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