Hi List,
from Emacs Lisp I know some special constructs for differenciating
between types of function arguments, e.g.:
,------------------------------------------
| (defun foo (x y &optional z &rest r) ...)
`------------------------------------------
When looking at the signature of e.g. the vi function in lib/debug.l:
,--------------------
| (de vi ("X" C) ...)
`--------------------
and then in the doc:
,------------------------------------------------------------------------------
| (vi 'sym) -> sym
| (vi 'sym 'cls) -> sym
| (vi '(sym . cls)) -> sym
| (vi) -> NIL
| Opens the "vi" editor on the function or method definition of sym. A call
| to ld thereafter will load the modified file. See also doc, edit, *Dbg,
| debug and pp.
|
| : (vi 'url> '+CuSu) # Edit the method's source code, then exit from 'vi'
| -> T
`------------------------------------------------------------------------------
its a bit hard to relate the signature to the documentation.
The chapter "Defining functions" in the PicoLisp tutorial
(http://software-lab.de/doc/tut.html#fun) explains many ways (and
tricks) how to define function args, but '(de vi ("X" C) ...)' looks to
me like a list of two parameters - why can it be called with 0 to 2
parameters (apparently)?
--
cheers,
Thorsten
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