Visually, font ligatures do just that, and combine your !=, >=, etc. into single elements
It then becomes important to see the difference between ASCII approximations and real Unicode symbols, since this is relevant e.g. when searching for a symbol in your code base or to see at a glance whether usage of Unicode vs. ASCII etc. is consistent.
The only spot I still kinda use such a feature (prettify-symbols-mode specifically) is in LaTeX, where Unicode math is more rare and long equations become nearly unreadable without some kind of rendering in the source code.
So I understand how you could have confusion in your case if you have logical comparators for ≥ and also have strings with "≥" or even variable names, if your language is permissive enough to allow that. But if you search for "≥" it should not return the ">=" disguised as "≥", ...right?
That’s my issue :). Languages like Julia permit both “>=" and "≥" in the source code with the same meaning. But if you use say search-based navigation of your file, how do you know which one to type to get where you want?
Or in Python I’ve seen some people make “alpha” render as α, since it’s a common variable name in physics codes. But “α” itself is a valid Python variable name, and I personally use Greek letters in Python physics code and know others do as well. That can again be confusing, since in Python “alpha” and “α” are not the same variable, so it’s crucial to write it correctly.
For example,
<C-k> -> gives →
<C-k> => gives ⇒
<C-k> d* gives δ (greeks are generally all _letter_*)
<C-k> D* gives Δ
- Like the sibling mentioned, you can use a “compose key” (it’s built in on Linux and can be installed on other platforms). There are other OS-wide options like the TeX input method for Gnome, or TextExpander snippets on Mac.
- In Vim, Ctrl-K in insert mode lets you enter “digraphs”. For instance, Ctrl-K *s will insert a Greek letter “sigma”.
- In Emacs, C-\ will activate an “input method” such as the “TeX” input method that can insert any math or Greek Unicode symbol using LaTeX notation. (I personally like Emacs’ “transient” input method that is activated for one symbol at a time, since it interferes less with coding.)
- In Sublime Text and VSCode there are third-party plugins that insert Unicode symbols via e.g. TeX notation.
- Every Julia editor extension, as well as its REPL, lets you press tab to convert a set of LaTeX-like notations into Unicode symbols in a common way.
- Most editors have support for snippets of some kind, and many have available snippet packs for common math and Greek symbols.
You might also be able to set up your own compose codes in ~/.XCompose, but that didn't work for me. Could be another casualty of Wayland or just some quirk in my setup.