Missing dependencies for package `forest`, `environ`

[Maximilian Nöthe]

Hi,

I tried this already at some point, and was bitten by exactly this.

Some packages use `usepackage`, some `RequirePackage`, I even saw some,
which created there own macro, internally doing something like 
`\RequirePackage{#1}`,
which made this such a hard problem it was virtually impossible.

I found some missing requirements, but many false positives or optional 
dependencies or
not found dependencies, that it wasn't really worth it.

Without a proper mechanic to declare dependencies that also supports 
optional dependencies,
this is an unsolvable problem and the only thing that will be able to 
solve this in part is to download
a known file if it is not found in the system.

This however will still create problems as there is no way to specify 
versions, so the download might
fetch a newer, incompatible version.

Regards
Max

On 11.01.21 10:10, Zdenek Wagner wrote:
> po 11. 1. 2021 v 0:38 odesílatel G. Cassian Alexandru
> <g.cassian.alexandru at posteo.eu> napsal:
>> Missed one, `tikz` (so pgf).
>>
>> And `environ`, one of its dependencies, has an undeclared dependency on
>> `trimspaces`.
>>
>> Maybe it would be an idea to go through the ctan database some time and
>> just find all uses of `RequirePackage` to semi-automatically improve
>> this situation?
>>
> This would not be so difficult, I always install scheme-full hence
> making such a script is a matter of minutes. However, it would create
> too many dependencies. For instance, my zwpagelayout needs color only
> conditionally. If you do not prepare crop marks in color, the package
> is not loaded. A few packages are loaded only if they are already
> installed and zwpagelayout then offers additional functionality, if
> they are not found, some functionality is disabled. It also matters
> whether the package is used with xelatex, pdflatex, or latex with
> dvips. It makes no sense to require pdflatex-support packages if a
> user wants xelatex only. There may be more such packages.
>
> This leads me to a question. There are hard dependencies (needed
> always) and soft dependencies (needed if a special functionality is
> requested). Is there a conditional dependency? For instance, hard
> dependency for use in xelatex but not needed at all with other
> engines.
>
> Zdeněk Wagner
> http://ttsm.icpf.cas.cz/team/wagner.shtml
> http://icebearsoft.euweb.cz
>