bug(mac): Hotkeys failed to switch before & after input modifier for IPA (SIL) keyboard

[Meng-Heng]

Describe the bug

Originated from https://community.software.sil.org/t/keyman-hotkey-ordering-after-install-on-mac/11221

Reproduce the bug

1. Launch TextEdit
2. Ensure IPA (SIL) keyboard is enabled
3. Type b=, resulted in β
4. Press RIGHT OPTION + - to switch to BEFORE option for input modifier
5. Type =b, resulted in =b

Expected behavior

The hotkeys should work to switch between BEFORE and AFTER as mentioned in the community site.

Related issues

#14675

Keyman apps

• Keyman for Android
• Keyman for iPhone and iPad
• Keyman for Linux
• Keyman for macOS
• Keyman for Windows
• Keyman Developer
• KeymanWeb
• Other - give details at bottom of form

Keyman version

19.0.198

Operating system

macOS Sequoia 15.7.4

Device

MacBook Pro

Target application

TextEdit

Browser

No response

Keyboard name

https://keyman.com/keyboards/sil_ipa

Keyboard version

2.0.2

Language name

Undetermined

Additional context

No response

[ermshiperete]

Also not working on Linux → #15693.

[mcdurdin]

This puzzled me.

Then I took at look at the sil_ipa source and I think the problem is actually because the rules depend on some functionality which is currently Windows-only -- virtual character keys:

$keymanonly: + [RALT "-"]	>	set(option_key='before') c 
c German keyboard has } on RALT+0 == RALT+= so use RALT SHIFT = instead for reset
$keymanonly: if(&baselayout = 'de-de') + [RALT SHIFT "="]	>	reset(option_key)  c 
$keymanonly: if(&baselayout != 'de-de') + [RALT "="]	>	reset(option_key)  c 

In the lines above, we use virtual character keys such as [RALT "-"] and not [RALT K_HYPHEN] which are related to mnemonic layouts. It seems that these do not currently work on mac or Linux -- though they should, as it should fall back to en-US.

Some other notes to help avoid confusion:

1. The &baselayout check will be relevant only on Windows at this time. The RALT+= test t will fallback to the rule with != 'de-de' because en-us is hardcoded on mac and Linux platforms.

2. The $keymanonly: compile target is okay, because that is a compile target so the .kmx will include these rules.

I have built a test version of sil_ipa which switched off mnemonic layouts and the option worked as expected on mac.

So that's the real bug: virtual character keys should work on mac and Linux, but don't appear to. The mnemonic layout recompiler will address this, so suggest we proceed down that path rather than attempting to mitigate in other ways in the Keyman source. We could build a positional sil_ipa keyboard for users in the meantime.