Functions as arguments in xlisp

[Doug Nelson]

Can someone explain to me why the following does not work in xlisp 3.02?

> (defun dof (f a b) (f a b))
dof
> (dof #'+ 2 3)
error: unbound function - f
if continued: try evaluating symbol again
1>

In an older DOS version of xlisp, I get the expected answer:
> (defun dof (f a b) (f a b))
DOF
> (dof #'+ 2 3)
5
>

I'm stumped.
Doug

[David Betz]

It must have been a *very* old DOS version of xlisp. The problem is that
there is a different namespace for functions and variables. To call a
function passed in as an argument you need to use funcall:

(defun dof (f a b) (funcall f a b))

--
David Betz
db...@xlisper.mv.com

[Erik Naggum]

* Doug Nelson

| Can someone explain to me why the following does not work in xlisp 3.02?

I'll take a wild guess.

| > (defun dof (f a b) (f a b))
| dof
| > (dof #'+ 2 3)
| error: unbound function - f
| if continued: try evaluating symbol again
| 1>

(defun dof (f a b) (funcall f a b)) should work. I guess xlisp 3.02
adheres to the standard Lisp way of not evaluating the functional
position in a form.

| In an older DOS version of xlisp, I get the expected answer:

this is the standard Scheme way, and I think you could only expect that
answer if you were thinking in Scheme terms.

#:Erik
--
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