Choice of processor

[Joseph Wright]

On 05/03/2025 12:42, Philip Taylor wrote:
>
> On 05/03/2025 12:30, Joseph Wright wrote:
>>
>> Yes - token.new() creates a character token with the given catcode -
>> compare with token.create() which will default to the current catcode
>> table. All covered (a bit) in the LuaTeX manual.
>
> Thank you Joseph.  I have read (and re-read) the LuaTeX manual, but I
> have not found it entirely satisfactory — for example, on page 235, near
> the bottom, there is an example line which reads :
>
> \immediate\useimageresource{foo.pdf}%
>
> yet when I paste that into an otherwise empty LuaTeX source file and
> attempt to compile it, I am told :
>
> This is LuaTeX, Version 1.18.0 (TeX Live 2024)
>   restricted system commands enabled.
> (./untitled-5.tex
> ! Missing number, treated as zero.
> <to be read again>
> {
> l.1 \immediate \useimageresource {
>                                  foo.pdf}
> ?

That's a typo: Hans has swapped over \saveimageresource and
\useimageresource - it happens.

> and indeed, there does not seem to be any formal definition of either
> \useimageresource or \loadimageresource — they are /discussed/, but
> never /defined/, as far as I can see (certainly not a formal syntax
> definition).
>

No, neither XeTeX nor LuaTeX have formal definitions in the same way TeX
does - the LuaTeX manual is more like most other programming references
I'm familiar with, it has some gaps.

Joseph