website/lib/Pandoc.rakumod

49 lines
1.5 KiB
Raku

#| Interaction with pandoc
unit module Pandoc;
use JSON::Fast;
sub markdown-title(IO::Path:D $file --> Str:D) is export {
# Call into pandoc
my $pandoc = run 'pandoc', '-t', 'JSON', $file, :out, :err;
my $output = $pandoc.out.slurp: :close;
my $stderr = $pandoc.err.slurp: :close;
# Throw an error if pandoc failed
if !$pandoc {
die "Pandoc exited with {$pandoc.exitcode}\nout: $output\nerr: $stderr";
}
# Parse out output from pandoc, we are making an executive decision to trust
# pandoc here, so we won't do any error handling for pandoc's output
my $parsed = from-json $output;
# Extract a list of top level headers from the pandoc output, this should
# only have one element in it, but as this is user input, its untrusted and
# we need to do some error handling
my @headers = $parsed.blocks.grep(*.t == "Header").grep(*.c[0] == 1);
if @headers.elems > 1 {
die "More than one top level header in $file";
};
if @headers.elems == 0 {
die "No top level hearders in $file";
};
# Extract the header and process it into a string
my @header = @headers[0].c[2];
my $title = "";
for @header -> $component {
given $component.t {
when "Str" {
$title = $title ~ $component.c;
}
when "Space" {
$title = $title ~ " ";
}
default {
die "Invalid component type: $_";
}
}
}
return $title;
}