Plus42

PRTRACE fixes and improvements.

Implemented try/catch style error handling: TRY, TRYX, CATCH?, PRTRACE. See the Free42 web site for details. RTNERR and RAISE support five additional error numbers; see the Free42 web site for details. Keyboard mapping now uses a platform-independent syntax. The existing keymap.txt is renamed to keymap.old, and a new keymap.txt is created, using the new syntax. All the skins in the Plus42 skins collection that contain keyboard mappings have been updated to take advantage of the new syntax, but the old syntax is also still supported, but only in skins, not in keymap.txt. Direct XEQ mapping: Skins can now define macros that perform an XEQ that works regardless of which menu is active, using the syntax `FOO` to perform XEQ "FOO". Implemented MENU1: This works just like MENU, i.e. it opens the Programmable Menu, except MENU1 opens the menu as an application menu, rather than as a regular menu. This means that MENU1 allows users to interact with command menus without losing their place in the programmable menu. Flag 33 is now automatically cleared whenever a non-programmable-menu key is pressed. This can be used to implement VARMENU-like behavior using the programmable menu. Implemented IP→S, a function that converts the integer part of a number to a string, like AIP, except the string is placed in the X register, not ALPHA. Fixed NORM/TRACE output for programmable menu. Added keyboard shortcut for Show Print-Out. Windows and MacOS versions: When a skin is selected that is too large to fit on the screen, it is now automatically scaled down to fit, while preserving its aspect ratio.

Fixed RLN and RRN for negative numbers in BSIGNED mode.