Checking if a function is built-in

Checking if a function is built-in

[Nordlöw]

Is there a predicate that can check if a function is built-in?

Thanks,
Nordlöw

Re: Checking if a function is built-in

[Marc Tfardy]

Nordlöw schrieb:
> Is there a predicate that can check if a function is built-in?

,----[ C-h f fboundp RET ]
| fboundp is a built-in function in `C source code'.
| (fboundp symbol)
|
| Return t if symbol's function definition is not void.
|
| [back]
`----

regards
marc

Re: Checking if a function is built-in

[Lennart Borgman (gmail)]

Marc Tfardy wrote:
> Nordlöw schrieb:
>> Is there a predicate that can check if a function is built-in?
> 
> ,----[ C-h f fboundp RET ]
> | fboundp is a built-in function in `C source code'.
> | (fboundp symbol)
> |
> | Return t if symbol's function definition is not void.
> |
> | [back]
> `----


This does not check if a function is built-in, but it gives a hint actually.

Look at the code for `describe-function'. Somewhere it writes "built-in".

RE: Checking if a function is built-in

[Drew Adams]

> Is there a predicate that can check if a function is built-in?

subrp 

RE: Checking if a function is built-in

[Drew Adams]

> > Is there a predicate that can check if a function is built-in?
> 
> subrp 

I should have added that `i' in the Elisp manual, then typing `built-in TAB'
gets you to node `What Is a Function', which describes `subrp'.

`i' is your friend in Info. The indexes have improved a good deal in recent
releases, thanks in particular to Eli's efforts.

If you find something that you think should be indexed but is not, please point
it out here or via `M-x report-emacs-bug'. 

Re: Checking if a function is built-in

[Nordlöw]

On 10 Juni, 23:50, "Drew Adams" <drew.ad...@oracle.com> wrote:
> > Is there a predicate that can check if a function is built-in?
>
> subrp

Thanks again, Drew!

I wonder why there isn't an alias builtinp() for this? I will create
one ;)

Thanks,
Nordlöw

Re: Checking if a function is built-in

[Nordlöw]

On 10 Juni, 23:50, "Drew Adams" <drew.ad...@oracle.com> wrote:
> > Is there a predicate that can check if a function is built-in?
>
> subrp

I thought this was the way to use it
  (subrp 'cons)
but it returns nil even though cons is a built-in function.

Have I missed something?

Thanks,
Nordlöw

RE: Checking if a function is built-in

[Drew Adams]

> > > Is there a predicate that can check if a function is built-in?
> >
> > subrp
> 
> I thought this was the way to use it (subrp 'cons)
> but it returns nil even though cons is a built-in function.
> Have I missed something?

(subrp (symbol-function 'cons))

`cons' is just a symbol. What you want to test is the function that the symbol
refers to. 

This is not the value of the symbol but the value of its function cell, which is
a function (a subr, in this case).

Re: Checking if a function is built-in

[Nordlöw]

On 11 Juni, 00:51, "Drew Adams" <drew.ad...@oracle.com> wrote:
> > > > Is there a predicate that can check if a function is built-in?
>
> > > subrp
>
> > I thought this was the way to use it (subrp 'cons)
> > but it returns nil even though cons is a built-in function.
> > Have I missed something?
>
> (subrp (symbol-function 'cons))
>
> `cons' is just a symbol. What you want to test is the function that the symbol
> refers to.
>
> This is not the value of the symbol but the value of its function cell, which is
> a function (a subr, in this case).

Great!

Now I got it!

Many Thanks,
Nordlöw