Creating args from list

[chrisf]

I'm trying to work out a way of providing mutliple arguments to a function, where the arguments are held in a variable as a list. I've got a stripped down example of what I'm trying to do:

Code: Select all

(defun print-record (format-str &rest args)
  (format t format-str args))

(print-record "~A ~A~%" 'first-arg 'second-arg)

The format string doesn't expect a list for its arguments, so this fails. I was hoping that 'multiple-value-call' might work, but it keeps list arguments as lists too e.g.:

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   (multiple-value-call #'format (values t format-str args))

(yes, I know that 'format' can iterate over a list to print multiple records, but that isn't what I want here).

Is there any way to do this with CL ?

Cheers,
Chris

[Geoff Wozniak]

You want to use apply.

Code: Select all

(apply #'format t format-str args)

See if that does what you want.

[chrisf]

Thanks - that worked a treat

You can probably tell I'm new to CL.

Cheers,
Chris

[Geoff Wozniak]

Hey, that's what we're here for.

If you have questions about what #'format really means, feel free to ask.

[gutzofter]

That is exactly what I was looking for. I'm use to doing funcall. Woohoo this should work!

Thanks a bunch!

[Harleqin]

This is interesting. Read up on a spreadable argument list designator.

[findinglisp]

This is interesting. Read up on a spreadable argument list designator.

I learn so much just from reading the CLHS glossary. It's amazing all the little tidbits lurking in there.