jsNGParser

This module contains tools for handling the formatting of the content of Norton Guide files. It exports the following:

Line.Parser( params )

This is a function that lets you turn Norton Guide formatted text into something useful for your application. It is done by passing an object that contains functions that will react to specific formatting events. Those events are:

text

Called any time processed text should be added to your output.

colour( attr )

Called any time a colour should be set. attr is the colour value that should be set. Please consult any old DOS programmer’s manual for the colour values this represents.

normal

Called any time the text attributes should be set back to normal. A call to set to normal generally means that all other active attributes should be disabled.

bold

Called any time the following text should be bold. Bold should be stopped if unbold or normal are called.

unbold

Called if bold should be stopped. Defaults to calling normal if not provided.

reverse

Called any time the following text should be set to reverse. Reverse should be stopped if unreverse or normal are called.

unreverse

Called if reverse should be stopped. Defaults to calling normal if not provided.

underline

Called any time the following text should be set to underline. Underline should be stopped if ununderline or normal are called.

ununderline

Called if underline should be stopped. Defaults to calling normal if not provided.

charval( char )

Called when a specific character should be added to the output. The value given will generally be one that represents a character in code page 447.

Using the above, it should be possible to create any form of output based on the text in a guide entry. Here’s an example where Line.Parser is used to strip all markup from the text:

const NGParser = require( "jsNGParser" );
let   s        = "";

// Assume line has come from a guide.

( new NGParser.Line.Parser( {
  text:    t => s += t,
  charVal: c => s += String.fromCharCode( c )
} ) ).parse( line );

console.log( s );
}

As a slightly more involved example, here’s the code of toTerminalText:

// Parse a NG line into text that's terminal-friendly.
function NGLine2TerminalText( line ) {
    "use strict";

    const FG_MAP = [
        "0;30", "0;34", "0;32", "0;36", "0;31", "0;35", "0;33", "0;37",
        "1;30", "1;34", "1;32", "1;36", "1;31", "1;35", "1;33", "1;37"
    ];
    const BG_MAP = [
        "40", "44", "42", "46", "41", "45", "43", "47",
        "40", "44", "42", "46", "41", "45", "43", "47"
    ];

    const esc = ( s ) => "\u001b[" + s;
    let   s   = "";

    ( new NGLineParser( {
        text:      t  => s += MakeDOSish( t ),
        colour:    c  => s += esc( FG_MAP[ c & 0xF ] + ";" + BG_MAP[ c >> 4 ] + "m" ),
        normal:    () => s += esc( "0m" ),
        bold:      () => s += esc( "1m" ),
        reverse:   () => s += esc( "7m" ),
        underline: () => s += esc( "4m" ),
        charVal:   c  => s += MakeDOSish( String.fromCharCode( c ) )
    } ) ).parse( line );

    return s + esc( "0m" );
}

Line.toPlainText( line )

Utility function that takes a line of NG marked-up text and converts it to plain text. All attributes are dropped and all text is, where possible, turned into “pure ASCII” text. This can be handy if you want to quickly generate some text from the guide.

For example:

const NG       = require( "jsNG" );
const NGParser = require( "jsNGParser" );
const entry    = ( new NG.Guide( "test.ng" ).open().goFirst().loadEntry();

entry.lines().forEach( ( line ) => console.log( NGParser.Line.toPlainText( line ) ) );

Line.toTerminalText( line ))

Utility function that takes a long of NG marked-up text and converts it to coloured text, complete with CP437 to utf-8 character conversions, such that it should be suitable for display in an ANSI terminal. This can be handy if you quickly want to render an entry in a terminal display.

For example:

const NG       = require( "jsNG" );
const NGParser = require( "jsNGParser" );
const entry    = ( new NG.Guide( "test.ng" ).open().goFirst().loadEntry();

entry.lines().forEach( ( line ) => console.log( NGParser.Line.toTerminalText( line ) ) );

The jsNGParser module also exports a couple of handy utility functions that should help with converting from CP437 text to something more useful:

Tool.makePlain( s )

Utility function that takes a body CP437 text and turns it into “plain” text. All lower and most upper characters are turned into a “.” and most box-drawing characters are turned into ASCII-friendly characters that come close to making sense (things like “|”, “-“ and “+”).

Tool.makeDOSish( s )

Utility function that takes a body of CP437 text and turns it into utf8 text that should look more or less the same. Handy if you want to try and make the output of a guide look similar to how it would have in the original Norton Guide reader on a DOS machine.