There has been discussion of this here:

https://forum.colemak.com/viewtopic.php?id=524

I'm not a programmer, but having the most commonly used punctuation symbols nearer to the home row is very easy by remapping the /? key to AltGr, as discussed in the above link. As Tomlu has pointed out in that thread, finding a low same finger, minimal row/hand jumping layout is not easy. Mainly due to the requirements of different programming languages. I have the left side of the 'board set up like this:

! ? + = *  < Q W F P G
- _ ( ) @   < A R S T D
| \ / & %  < Z X C V B

I'm still undecided on the right side of 'board. This works very well for me as a non-programmer (I attempt to learn then quickly throw in the towel).

The word is that Shai would not want to include this as a part of Colemak, which I understand. Too much memory burden for the new user plus it would be very hard to have a standard Alt. layout that would appeal to all programmers.

Why do you say that? Using Qwerty (or standard Colemak), programmers have all brackets same hand...

Plus, using Python which often has (), it makes for a nice inward roll.

Unless you have dedicated non-modified keys for your brackets, or you access them with a foot pedal, you will find that putting them on opposite hands is painful. Either you chord correctly and have to switch modifier hand every other keystroke, or you do not chord correctly - along with its concomitant disadvantages.

The space bar was attempted for the mirrored "half"-colemak as you'll recall. I think it's a horrible idea since it's the most used of all keys and therefore mixups will be that much more common. I never tried it a lot, but enough to get this impression at least.

Its' beauty lies in the symmetry: For the mirrored Colemak for instance, you could type right-handed or left-handed without remapping more than one modifier. Too bad it's too problematic. What I've found to work though, is the old B key when you move the ZXCVB one step to the left. In the "comfort Colemak" layout in PKL that key becomes an Enter key which is a decent enough idea, but it could just as well become a new modifier. Symmetric, hardly used beforehand and all in all a good choice I think.

Not sure what you're saying here; that a semicolon is invariably followed by whitespace? This certainly isn't the case for me. I'm prone to writing semicolon-delimited lists for instance. If you just release the semicolon character with space, will it be too annoying to have to type the other space directly afterwards?

The other way of implementing this is the combined-hotkey way with AutoHotKey. Releasing the semicolon alone would then produce the semicolon, but if you depressed something else first you'd get the corresponding symbol. You could use the PKL program if you want to, redefining the 'extend key' to semicolon and the 'extend' mappings to yours.

Your brackets could have been a bit more aligned, maybe? I think that for instance Tomlu's layout is easier on the eye. Try to imagine that someone else sees your layout for the first time and hasn't got a lot of time and energy to learn everything; how will you make it easier for them both to learn and later to use?

My five cents' worth:

If you design the layout carefully, you don't need any of ==, <=, >=, !=, +=, -=

Instead, separately place all of =, >, <, !, +, - such that they roll nicely. You'll save space.