Free42 with big stack, test version

[Thomas Okken]

After giving this some more thought, I think there are two major use cases here: one the one hand, people who are perfectly happy with the four-level stack and have no interest in the big stack feature, and on the other hand, people who like the big stack feature and could imagine using it occasionally.

The former would be best served by the big stack feature not existing at all. If it's not there, there's no chance of accidentally activating it and having programs fail etc.

The latter should understand how the differences between four-level and big stack mode affect programs, and thus understand the importance of making sure the appropriate mode is used for any given task.

I don't think there is much value in safety features, like LBL automatically forcing four-level mode. Big stack users won't really need them, they can figure out where to insert 4STK or L4STK into legacy programs as needed. And for people who prefer to use the four-level stack exclusively, such safety features probably won't go far enough.

So here's another proposal: I leave the big stack functionality exactly like it is now, with no changes to the semantics of FUNC, 4STK, NSTK, L4STK, or LNSTK... and I add a setting to the Preferences to completely disable the big stack. Completely disable, as in: removing the STK section under CATALOG, removing 4STK and NSTK from MODES, turning off big stack mode if it happened to be active, and making all big-stack-related functions raise a Big Stack Disabled error when they are executed in a program. This master setting will be set to "big stack disabled" by default.

(And this whole story will apply to the basic Free42 as well as Free42+.)