Typing ALGOL code correctly – how to?

Question

This is retrocomputing. We sometimes need to type code in old languages.

In particular, if I am to be able to write Algol in the publication language, I need a bold font. But I also need my text to be laid out as typed - line breaks and indentation included.

It seems that code-style and bold do not go together.

    **comment** this makes me sad;

I discovered I can get line-breaks to remain outside of a code block by having a couple of spaces before the end of line, but I have not yet found a way to keep indentation.

Is there some way to type Algol correctly? (Without resorting to stropping conventions)

For what it's worth, I don't need a monospaced typeface. That wasn't a necessary thing in Algol publications.

Answer 1

Type HTML directly.

<pre><code>    <b>comment</b> this makes me sad;
second line
    with <i>indentation</i> too!
</code></pre>

produces:

    comment this makes me sad;
second line
    with indentation too!

This isn't a good solution, but it works. The limitations of the medium, and all that.

Answer 2

As an alternative to formatting keywords with raw HTML, you could use Unicode “mathematical bold” characters.

    𝐜𝐨𝐦𝐦𝐞𝐧𝐭 this makes me sad;

𝐢𝐧𝐭𝐞𝐠𝐞𝐫 𝐩𝐫𝐨𝐜𝐞𝐝𝐮𝐫𝐞 square(n);
    𝐯𝐚𝐥𝐮𝐞 n; 𝐢𝐧𝐭𝐞𝐠𝐞𝐫 n;
    square := n × n;

𝐩𝐫𝐨𝐜 square = (𝐢𝐧𝐭 n) 𝐢𝐧𝐭 :
    (n × n);

Unlike some other uses of Unicode mathematical bold (bypassing the lack of availability of formatting markup, especially when shitposting), this is arguably a correct use of those characters: they were meant to be used when writing mathematical notation, where what would otherwise be purely stylistic formatting may carry semantic meaning. To the extent you can consider computer code a form of mathematical notation (which, I think, is not that much of a stretch), this is pretty much exactly what happens here.

Advantages of this approach: the bolding is preserved even when you copy the code as plaintext (unlike HTML formatting), and it may be easily converted to stropped form via little more than search-and-replace. Disadvantages: some systems may lack the necessary font support to display the characters, and even on those that do support them, the characters may render as proportionally-spaced, even if the ambient font is fixed-width, which means column-aligned spacing is going to be spoiled. Also, some poorly-written screen readers will not be able to read it.

Since inputting those characters can be a hassle, here’s a short, hastily-written user script to make that easier (known to work on Firefox 91 ESR with Greasemonkey):

// ==UserScript==
// @name     𝐀𝐥𝐠𝐨𝐥𝐢𝐳𝐞𝐫.
// @grant    none
// @match    https://retrocomputing.stackexchange.com/*
// @match    https://retrocomputing.meta.stackexchange.com/*
// ==/UserScript==

const embolden = text => {
  text = text.replace(/[A-Z]/g, c =>
    String.fromCodePoint(c.charCodeAt(0) - 0x41 + 0x1d400));
  text = text.replace(/[a-z]/g, c =>
    String.fromCodePoint(c.charCodeAt(0) - 0x61 + 0x1d41a));
  text = text.replace(/[0-9]/g, c =>
    String.fromCodePoint(c.charCodeAt(0) - 0x30 + 0x1d7ce));
  return text;
};

const link = document.createElement('a');
link.accessKey = ';';
link.addEventListener('click', ev => {
  const textarea = document.querySelector('input:focus, textarea:focus');
  if (!textarea || textarea.value == null)
    return;
  let text0 = textarea.value.substring(
    textarea.selectionStart, textarea.selectionEnd);
  if (!text0)
    text0 = prompt('Enter text');
  const text1 = embolden(text0);
  const cur = textarea.selectionStart;
  textarea.focus();
  document.execCommand('insertText', false, text1);
  textarea.selectionStart = cur + (text0 ? 0 : text1.length);
  textarea.selectionEnd = cur + text1.length;
});
document.body.appendChild(link);

After installing the script with your favourite method of instaling user scripts, press Alt+; or Alt+Shift+; (this may vary depending on your browser) to activate and enter the ALGOL keyword in ASCII characters. The script should replace ASCII letters and numbers within the selected text with their mathematical bold counterparts. With an empty selection, it will prompt you for the word to insert.