pandoc-html-manpage-filter.js

//
// Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
// DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
//
// This code is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License version 2 only, as
// published by the Free Software Foundation.
//
// This code is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
// version 2 for more details (a copy is included in the LICENSE file that
// accompanied this code).
//
// You should have received a copy of the GNU General Public License version
// 2 along with this work; if not, write to the Free Software Foundation,
// Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
//
// Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
// or visit www.oracle.com if you need additional information or have any
// questions.
//

//
// Traverse a tree of pandoc format objects, calling callback on each
// element, and replacing it if callback returns a new object.
//
// Inspired by the walk method in
// https://github.com/jgm/pandocfilters/blob/master/pandocfilters.py
//
function traverse(obj, callback) {
    if (Array.isArray(obj)) {
        var processed_array = [];
        obj.forEach(function(elem) {
            if (elem === Object(elem) && elem.t) {
                var replacement = callback(elem.t, elem.c || []);
                if (!replacement) {
                    // no replacement object returned, use original
                    processed_array.push(traverse(elem, callback));
                } else if (Array.isArray(replacement)) {
                    // array of objects returned, splice all elements into array
                    replacement.forEach(function(repl_elem) {
                        processed_array.push(traverse(repl_elem, callback));
                    })
                } else {
                    // replacement object given, traverse it
                    processed_array.push(traverse(replacement, callback));
                }
            } else {
                processed_array.push(traverse(elem, callback));
            }
        })
        return processed_array;
    } else if (obj === Object(obj)) {
        if (obj.t) {
            var replacement = callback(obj.t, obj.c || []);
            if (replacement) {
                return replacement;
            }
        }
        var processed_obj = {};
        Object.keys(obj).forEach(function(key) {
            processed_obj[key] = traverse(obj[key], callback);
        })
        return processed_obj;
    } else {
        return obj;
    }
}

//
// Helper constructors to create pandoc format objects
//
function Space() {
    return { 't': 'Space' };
}

function Str(value) {
    return { 't': 'Str', 'c': value };
}

function MetaInlines(value) {
    return { 't': 'MetaInlines', 'c': value };
}

function change_title(type, value) {
    if (type === 'MetaInlines') {
        if (value[0].t === 'Str') {
            var match = value[0].c.match(/^([A-Z0-9]+)\([0-9]+\)$/);
            if (match) {
                return MetaInlines([
                        Str("The"), Space(),
			Str(match[1].toLowerCase()),
			Space(), Str("Command")
		    ]);
            }
        }
    }
}

//
// Main function
//
function main() {
    var input = "";
    while (line = readLine()) {
        input = input.concat(line);
    }

    var json = JSON.parse(input);

    var meta = json.meta;
    if (meta) {
        meta.date = undefined;
        var title = meta.title;
        if (meta.title) {
            meta.title = traverse(meta.title, change_title);
        }
    }

    print(JSON.stringify(json));
}

// ... and execute it
main();