Plus42 Equations, Preview Release

[Thomas Okken]

It sounds like I should change #T() and FLOW() to work with 0-based indices, and have them simply add 1 to those indices before passing them to GETITEM. Although that wouldn't agree with the behavior of ITEM(). Yuck. It's a bit messy since on the 17B, Σ lists are addressed using SIZES() and ITEM(), while CFLO lists are addressed using SIZEC(), FLOW(), and #T(), so it's OK for them to have slightly different semantics. But in Plus42, it's all general-purpose matrices and lists under the hood.

The goal here is just to have the equation language be as compatible as possible with the original. The fact that there is a bit of ugliness with 0- vs. 1-based indices under the hood is inevitable at this point. HP started it, just consider what happens with PRV "REGS" on the HP-42S.

Regarding Σ lists, that's how you enter data points for statistical calculations on the 17B and its ilk. I haven't used them myself, all I know from reading the 17B manual is that they use 1-based indices, while CFLO lists use 0-based indices.