cannot find Text.Pandoc.JSON (needed for compilation ghc --make stripmath.hs)

[ouboub]

Hi
I asked this question years ago (and used it in Ubuntu 16.04 and the corresponding pandoc version). I am now on Ubuntu 24.04
using pandoc 3.1.3. I want to strip a latex file: all equations should be replaced by the word formula.
so the following was proposed to me by the pandoc author

import Text.Pandoc.JSON
    
main = toJSONFilter stripmath
    where stripmath (Math _ _) = Str "FORMULA"
          stripmath x = x

or even

import Text.Pandoc.JSON
    
main = toJSONFilter stripmath
    where stripmath (Math _ _) = Str "FORMULA"
          stripmath x = x
go (Math _ _) = Str "FORMULA"
go (Span (_,_,[("label",_)]) _) = Str "LABEL"
go x = x

both hs files should be compiled with

ghc --make stripmath-ref.hs
ghc --make stripmath.hs

however in my case this returns

import Text.Pandoc.JSON
    
main = toJSONFilter stripmath
    where stripmath (Math _ _) = Str "FORMULA"
          stripmath x = x
go (Math _ _) = Str "FORMULA"
go (Span (_,_,[("label",_)]) _) = Str "LABEL"
go x = x

I cannot find file i my Ubuntu distribution. I also pulled the github repository and still cannot find this file
What do I miss

Uwe Brauer

[ouboub]

>> "UB" == Uwe Brauer ***@***.***> writes: Hi I asked this question years ago (and used it in Ubuntu 16.04 and the corresponding pandoc version). I am now on Ubuntu 24.04 using `pandoc 3.1.3`. I want to strip a latex file: all equations should be replaced by the word formula. so the following was proposed to me by the pandoc author ``` import Text.Pandoc.JSON main = toJSONFilter stripmath where stripmath (Math _ _) = Str "FORMULA" stripmath x = x ``` or even ``` import Text.Pandoc.JSON main = toJSONFilter stripmath where stripmath (Math _ _) = Str "FORMULA" stripmath x = x go (Math _ _) = Str "FORMULA" go (Span (_,_,[("label",_)]) _) = Str "LABEL" go x = x ``` both `hs` files should be compiled with ``` ghc --make stripmath-ref.hs ghc --make stripmath.hs ``` however in my case this returns ``` import Text.Pandoc.JSON main = toJSONFilter stripmath where stripmath (Math _ _) = Str "FORMULA" stripmath x = x go (Math _ _) = Str "FORMULA" go (Span (_,_,[("label",_)]) _) = Str "LABEL" go x = x ``` I cannot find file i my Ubuntu distribution. I also pulled the github repository and still cannot find this file What do I miss

I installed via sudo apt-get install libghc-pandoc-types-dev Which seemed to have helped. However then the compilation gave the following error ``` [1 of 2] Compiling Main ( stripmath.hs, stripmath.o ) stripmath.hs:4:38: error: • Couldn't match type ‘[Char]’ with ‘Data.Text.Internal.Text’ Expected: Data.Text.Internal.Text Actual: String • In the first argument of ‘Str’, namely ‘"FORMULA"’ In the expression: Str "FORMULA" In an equation for ‘stripmath’: stripmath (Math _ _) = Str "FORMULA" | 4 | where stripmath (Math _ _) = Str "FORMULA" | ^^^^^^^^^ ``` So I have still problems

[jgm]

Add this to the top of your filter:

{-# LANGUAGE OverloadedStrings #-}

[ouboub]

Thanks, now it compiles, however when I run

stripmath rev-4701272.tex rev.txt

the program just hangs without any result.

[jgm]

This is a filter; you use it by running pandoc and specify --filter stripmath

[ouboub]

Ah, of course sorry, and the most efficient way seems to do this

pandoc --filter /home/oub/scripts/stripmath-ref rev-4701272.tex | pandoc -t plain -o new.txt

BTW all the stack/haskell/cabal installation seem not necessary?!

[jgm]

You don't need to precompile the filter, but you do need pandoc-types to be installed.

By the way you can simplify, you don't need a pipe:

pandoc --filter YOURFILTER INPUT.tex -t plain -o OUTPUT.txt

[ouboub]

I tried to install pandoc-types via cabal (and stack).
So first followed the instructions ghcup
which installed stack and cabal
but

cabal install --lib pandoc-types

leads to

cabal install --lib pandoc-types
Error: cabal: Packages requested to install already exist in the environment file
at /home/oub/.ghc/x86_64-linux-9.4.7/environments/default. Overwriting them
may break other packages. Use --force-reinstalls to proceed anyway. Packages:
pandoc-types

the force option does not do anything, so I am puzzled

[jgm]

PS. It's now much more convenient to use a Lua filter for this. See the documentation on the pandoc website under "Lua filters." Writing a Lua filter to reproduce what you're doing above should be a fairly simple task.