symbols in BEAKL mu are accessed via the index, middle and ring fingers of the thumb shift side hand. It is surprisingly effective but constrained by the range of keys comfortably reached by the hand in the thumb shift position. Larger hands can implement a larger shift layout but there is another more universal solution.
Enter the home row modifiers. These are key code modifiers, applied singly – except for the Shift key whose role is the responsibility of the thumb Shift, as implemented above – or as chords.
By assigning the home row Shift as a Symbol Layer key when held down singly (with no other modifiers), the opposite hand can now float over the Symbol Layer without any restriction. This is what the free hand toggled Regex Layer allowed..
home row symbols
Not every symbol character is mapped to these layers, as many are available from the base layer from which their usage in regular expressions and programming statements would be typed.
Rolls in expression construction and familiar keypad location for ease of memory are the design criteria – not necessarily key frequency, as rumination is more the order of the day when typing symbol expressions, than shear typing speed.
That said, I find this layout efficient for the kinds of expressions I type and, more importantly, easy to remember – the rationalization of its layout and organization can be deciphered.
freeing the hand from the thumb locked position to type symbols feels vastly superior but not without a restriction. Sloppy fingering while typing the home row shift characters, the A and T keys, can result in inadvertent symbol characters being typed – particularly for the TH bigram which finger memory develops very rapid fingering for.
So far, by paying attention to accurate touch typing, this problem can be avoided. But this problem may persist for fast typists. Adjusting QMK compilation timing parameters may be sufficient but assigning the symbol layer to a different modifier and, hence, home row character – dependent on one’s particular layout – may be the better solution.