Plus42 Equations, Preview Release

[Thomas Okken]

New update:

1. Basic unit support in equations. The syntax is slightly different from units in normal RUN and PRGM modes, in that the units must be enclosed in double quotes. So, instead of 16_oz, you write 16_"oz". What's going on here is that the units are actually string literals, and _ is a multiplicative operator that creates a unit object from a number on its left and a string on its right. (In compatibility mode, _ is an identifier character, so it's not available to use as an operator; in this case, the syntax UNIT(16:"oz") can be used instead.
2. Made number pasting a bit pickier, so it doesn't try to treat strings that start with E (like EXPM1(1)!) as numbers.
3. Can now create unit program lines with X2LINE.
4. Added UNIT? function.
5. Unit normalization: now replacing × ÷ ↑ with * / ^ in unit strings.