I am attempting to render text in Pashto in a Quarto pdf in r. Below my code:

---
title: "Pashto text"
format: 
  pdf:
    toc: true
    number-sections: false
    colorlinks: true
    pdf-engine: lualatex
include-in-header:
  text: |
    \usepackage{fontspec}
    \usepackage[bidi=basic]{babel}
    \babelprovide[import=ps,mapdigits]{pashto}
    \babelfont[pashto]{rm}[Renderer=HarfBuzz]{Amiri}
---

```{r setup, echo=FALSE, include=FALSE}
cat("\\selectlanguage{pashto} دا پښتو متن دی")
cat("\\n")
```

I get the following error:

installing hyphen-pashto (1 of 1)
ERROR: [non-error-thrown] tlmgr returned a non zero status code
tlmgr install: package hyphen-pashto not present in repository.
tlmgr: action install returned an error; continuing.
tlmgr: An error has occurred. See above messages. Exiting.

In my understanding, there is no hyphen-pashto package. Is there a workaround?

You can use fontspec and then create a new fontfamily pashtofont with Script=Arabic. Amiri seems to be not available, which is why I took Arial. The cat-output can be parsed as LaTeX if you put results = 'asis'. We then also have to use \\textdir TRT, otherwise cat will flip the arabic and this will change the meaning!

Option 1 (easy)

---
title: "Pashto text"
format: 
  pdf:
    toc: true
    number-sections: false
    colorlinks: true
    pdf-engine: lualatex
include-in-header:
  text: |
    \usepackage{fontspec}
    \newfontfamily\pashtofont[Script=Arabic]{Arial}
    
---
```{r test, echo=FALSE, include=TRUE, results='asis'}
cat("\\pashtofont \\textdir TRT دا پښتو متن دی")
```

giving

Option 2 with custom 'Amiri' font

You can download Amiri-Regular.ttf and put it in the same directory as your quarto file. Then use the following as outlined here

---
title: "Pashto text"
format: 
  pdf:
    toc: true
    number-sections: false
    colorlinks: true
    pdf-engine: lualatex
include-in-header:
  text: |
    \usepackage[bidi=default, nil]{babel}
    \usepackage{fontspec}
    \newfontfamily\psfnt[Renderer={Harfbuzz}]{Amiri-Regular.ttf}
    \DeclareTextFontCommand\pstxt{\psfnt}
    
---
```{r test, echo=FALSE, include=TRUE, results='asis'}
cat("\\textdir TRT \\pstxt{دا پښتو متن دی}")
```

Note:

• tinytex::install_tinytex() helps but will eventually still fail when used with babel and I tried lot's of things. This solution was given here and helped for the "tlmgr returned a non zero status code" error but not directly for this issue. How to reinstall tinytex. What you see here worked for me.