florianschwendinger / pandocfilters Goto Github PK

The existing documentation led me to believe that filter code such as the following, adapted from one of the examples given, would work:

require("pandocfilters", quietly = TRUE, warn.conflicts = FALSE)
caps <- function(key, value, ...) {
    if (key == "Str") return( Str( tolower(value) ) )
    return(NULL)
}
filter(caps, input = stdin(), output = stdout())

Invoking this with pandoc -F filter.r input.md (with input.md containing just one line with a few capitalized words) however throws the following error:

Error in filter(caps, input = stdin(), output = stdout()) : 
  InputError: The JSON-formatted AST for read in is empty!
Execution halted
Error running filter filter.r:
Filter returned error status 1

FWIW, I’m using pandoc version 2.11.1, and from inside R, executing the example code from “2.2.1. Lower Case” works as expected.

Any advice?