Monospace font for non-ascii chars

Question

I have some code that uses non-ASCII unicode chars. Here's a simple example that happens to be JS but the problem exists more generally:

function replaceFractions(text) {
  // We're ignoring ⅙⅚⅑⅐⅑⅒
  return text
    .replace(/([0-9])½/g, '$1.5')
    .replace(/([0-9])⅓/g, '$1.333')
    .replace(/([0-9])⅔/g, '$1.666')
    .replace(/([0-9])¼/g, '$1.25')
    .replace(/([0-9])¾/g, '$1.75')
    .replace(/([0-9])⅕/g, '$1.2')
    .replace(/([0-9])⅖/g, '$1.4')
    .replace(/([0-9])⅗/g, '$1.6')
    .replace(/([0-9])⅘/g, '$1.8')
    .replace(/([0-9])⅛/g, '$1.125')
    .replace(/([0-9])⅜/g, '$1.375')
    .replace(/([0-9])⅝/g, '$1.625')
    .replace(/([0-9])⅞/g, '$1.875')
}

As I see this in Stackoverflow, it's perfectly aligned as I'd expect it to be.

I'm using Monospace-12 in emacs via the following in .emacs:

(set-frame-font "Monospace-12")

If I look at it I see this:

There's bigger gaps than there should be between the 3/4 and 1/5 lines, the 1/5, 2/5, 3/5 and 4/5 are all taking more horizontal space and it's basically ugly. I get similar issues with superscripts (e.g. ⁰¹²³⁴⁵⁶⁷⁸⁹⁽⁾⁻⁺⁼ⁿⁱ)

Is there any way to get this so it's equal width for all chars not just a subset? Ideally I'd like it for all unicode chars but I can live without the weirder ones, emojis and so forth. What I do want is subscripts, superscripts, fractions, currency symbols to all be consistently spaced.

Answer 1

Your font doesn't include those characters, so it's using some other fallback font, and the fallback font size doesn't match.

The complex solution will be to set up fallback fonts that do include those characters, and also match the width of your primary font. This will involve "fontsets" and set-fontset-font (see this question and related).

I've had trouble figuring out fontsets, so I've used a simpler solution: use a font that includes more characters. For example, here's Iosevka:

and here's Menlo: