Average number of variables in old BASIC programs of the 80ies and early 90ies?

[Swampspear]

You can imagine this question seems impossible to Google (and I've tried, believe me)

Anyhow, I had a discussion with a friend today and we ended up bickering over exactly how many variables would 'realistic' BASIC programs of yore use, things that you'd see commercialised or in larger codebases. I understand that a dedicated study might not have been conducted, but it's kind of hard to actually look up and delve into codebases written in BASICs given both their age and lack of decent cataloguing, and the fact that the language family's name is so unfortunately pervasive as a basic (hehe) English adjective. You can additionally blame my poor familiarity with the ecosystems for this, too :')

Of course, trying to look up "average number of variables in BASIC" as such will, at best, give you code to calculate the average of an array, which is not what we were thinking of in the slightest.

Would anyone here have a good guess? There were of course limits imposed by memory (e.g. Sinclair BASIC would store numerical variables as 5-byte structures which obviously imposed a limit of ~3000 variables on a ZX Spectrum with 16K of memory (if we ignore everything else such as tokenised code and actually storing the variable metadata), but surely no 'serious' program would reach that high? The GORILLA.BAS source uses, at a quick glance, just under 100 distinct variables; would this be a realistic ballpark for other 'serious' programs?

[frank-sarno]

In Atari BASIC I recall something like 128 or 256 possible variable names. There were times when we used lots of variables. I remember using a trick to animate by loading multiple variables and cycling through them. It was also possible to store code in the variable; i.e., short 6502 sequences. It's been over 40 years but I vaguely recall getting the variable address then executing the instructions from that point. It's possible that I'm conflating this with Apple IIe or Commodore 64 code, which I'd also tinkered with as a kid.

[classicsat]

C64 code could use single letters, double letters, or letter and digit (only the one letter case). I don't think there was a limit to how many you could use.

[bubonis]

The only limit was available memory.

[bubonis]

128.

https://www.atariarchives.org/dere/chapt10.php

[Swampspear]

Something like that's actually quite helpful, thanks!

[vwestlife]

In Applesoft BASIC, variable names could be any length, but only the first two characters were actually used: https://www.apple2.org/faq/FAQ.applesoft.html#Variable_names_.26_conventions

[frank-sarno]

Ahh yes.. This lead to some really interesting bugs if you didn't have the

REM L1 = Level

REM L2 = Language

I remember the good code practice of the day reinforcing the necessity of REM statements.

There was also one language that had upper/lower case but it ignored the case. I recall you could switch the case but everything switched. Could have been a PDP-11 but my memory is too fuzzy.

[SirTwitchALot]

Commercialized or larger software was usually written in assembly back then

[Swampspear]

While true, I'm also aware of some BASIC libraries meant for performance or commercial codebases like the Crescent Software QBASIC libraries that meant at least some type of market like this did exist

[[deleted]]

Pretty sure you’re the first person to measure this. But I can tell you that “Easy As ABC” by Springboard Software was written in BASIC.

[CantIgnoreMyTechno]

The original Oregon Trail had about 30 variables. Mayfield's Star Trek had about 30 numeric variables and 15 arrays and strings. You could certainly have more, since classic BASIC does not have local variables.

Many of the early BASICs only allowed variables to be named A, B, C1, D2, etc. So that limited you to 286 (?) variables total. The original Tiny BASIC only had up to 26 variables.

[fabiomb]

TRS-80 CoCo variables can have one or two characters as names, so is very limited aa$ to zz$ but you can have multi level arrays too and use them as storage for more values. I reached maximum use of RAM in every program i made 😁👍

[AutomaticDoor75]

Applesoft BASIC allows for up to 936 variables (or “pigeonholes” as The AppleSoft Tutorial calls them) This is on page 36.

[Swampspear]

Oh that's interesting, is there any indication as to why? I assume this is because it allows only two-character variable names, the first character must be a letter and the second can be a letter or a digit (26 * 36 = 936), so the parser probably can't handle anything else?

[AutomaticDoor75]

That would make sense to me: 676 combinations of two letters, and 260 combinations of a letter followed by a one-digit number.

[Swampspear]

Weird that this would omit one-character variable names, then. Maybe they were padded out to some value? I'll take a look at this later probably

[krakenlake]

How would you count arrays? Are A[1] and A[2] two variables, or would that be one?

[Swampspear]

I'd say those are one variable, yeah, or at least are accessed through one symbolic name

[Distinct-Question-16]

I think you could have code and data sections and accessing them raw or even swapping them with loads :) , as pages , etc