41: What's the significance of the alpha mark (ᵀ) prefix on catalog 2 entries?

[hth]

(01-23-2020 10:10 PM)Dave Britten Wrote:  

(01-23-2020 10:01 PM)rprosperi Wrote:  Thanks for the correction! I never noticed that Functions taking arguments from existing Alpha register all came in or after the XFM, and that all mainframe functions did this the 'old' way. Like many such behavioral things, it makes sense, once you see the pattern.

I wonder why the switch. It's not like a function couldn't take an indirect argument the way XEQ IND does if you needed a non-hard-coded argument. Was it to get around the 6-character register limit maybe? But for that matter, I wonder why the 41 doesn't support IND A.

The original ROMs had severely underdeveloped programmable alpha functionality. This was rectified with the Extended Functions module.

The switch from prompting for the alpha name to using the alpha register was most likely caused by the file systems. Early on there were the card reader and the Wand, both which relied on physical media that the user picked manually. With the Extended functions and the HP-IL mass storage, there was multiple files and they were selected by name. In order to do this it was natural to use the alpha register. It also allowed for specifying a program by name and save it under a different name.