Trying to make a programming font with Ligatures and not sure where I’m going wrong

A number of new programming fonts use ligatures in a unique way to make coding easier.

typing <- will turn into ←
typing =/= will turn into ≠
typing >= will turn into ⩾

But it doesn’t change the character typed (which is very important in programming) just the way the font displays the character. Some more:

Anyway, I was trying to edit Courier New (the font i use for programming) to add these programming ligatures, but I don’t know where I’m going wrong.

Here’s a quick video of what I did so maybe people can see what I’m doing incorrectly:

For this ligature, I’m trying to get <- to display as ←

I know the end is the problematic part, but I can’t find good instruction on what to put in my code

OpenType features never change the character stream. Only the glyphs that are displayed. That is the whole point of OT features.

You added a lookup (why?) but as far as I can see, you did not add the lookup to a feature, so it will never be triggered.

How about you call the ligature less_hyphen (yes, hyphen, because I don’t think you can type an actual minus on the Mac and PC keyboards), and let the features be autogenerated. Read more about generating ligatures in this tutorial:

Also, you are working on a reverse-engineered font. After checking the legalese, there are a few technical things to consider. Please read these if you have not already: