Allow YAML header to specify a different documentclass

[jgrigera]

With this simple patch users can specify documentclass in the header and use alternative versions of the letter class, such as scrltr or others.

[aaronwolen]

Thank you @jgrigera!

[lamyergeier]

@jgrigera @aaronwolen

• With the above change I get a new error:

! Undefined control sequence.
l.64 \signature

Without this change I don't get this error!

[jgrigera]

Which documentclass are you using? Check your markdown- using this option you should choose letter compatible classes

…

On Wed, 9 Aug 2023, 02:26 Lamyergeier, ***@***.***> wrote: @jgrigera <https://github.com/jgrigera> @aaronwolen <https://github.com/aaronwolen> - With the above change I get a new error: ! Undefined control sequence. l.64 \signature Without this change I don't get this error! — Reply to this email directly, view it on GitHub <#36 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABYRCTYDVN2GK3ZZT7WS63XULRMJANCNFSM6AAAAAATIVVQDE> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[lamyergeier]

@jgrigera I didn't specify any document class:

$ \cat Sample.markdown 
---
author: Aaron
opening: To whom it may concern,
closing: Sincerely,
address:
- 123 Street Rd
- Chicago, IL
return-address:
- My Home
- 456 Road St.
- New York, NY
links-as-notes: true
---

Paragraph 1

> Paragraph 2

Paragraph 3

$ Template="${HOME}/Documents/Git/Linux/AmazingNotes/AmazingNotesSrc/MdRenderSpecial/Resource/PandocLetter/Resource/pandoc-letter/template-letter.tex"
$ Filename=Sample
$ dOutputP=Output
$ mkdir --parents "${dOutputP}"
$ pandoc --template="${Template}" ${Filename}.markdown -o "${dOutputP}/${Filename}.pdf"
Error producing PDF.
! Undefined control sequence.
l.57 \signature

[jgrigera]

Just checked and you are right! Apologies for this wrong commit @lamyergeier and @aaronwolen

I provided the patch without noticing that pandoc sets the documentclass to article by default and thus broke this template.
See:
[https://github.com/jgm/pandoc/blob/cc371a9485241db3e0101180432e2122d023a9bd/src/Text/Pandoc/Writers/LaTeX.hs#L109]

There is already a fix in the PRs, see #37. @aaronwolen can you accept the PR?

Apologies!
Juan