TI83Sharp

TI-Basic interpreter, compatible with TI-83 and TI-83+.

I built this interpreter because I had some old TI-BASIC scripts sitting on my computer that I felt like running again but my TI-83+ is buried in a box somewhere. Figured it was a good excuse to learn a few new things.

Note

This interpreter does not replicate the original calculator's execution timing.

Usage

.\TI83Sharp.exe --scripttext ":5(2^4-6)/3"
.\TI83Sharp.exe --scriptfile "program.bas"

Functionalities

Variables

Numbers, strings, lists and matrices are supported and have all their native operations implemented.

Optimizations

I’ve tried to preserve the optimizations available on the original calculator:

• Closing quotes, brackets, or parentheses can be omitted when they appear at the end of a line or just before a store token
• DelVar commands can be used without separating them with a colon

Currently not supported:

• Possibility to omit the starting character of custom list names in certain scenarios

Tokens

Category	Token
Control Flow	If, Then, Else, For(, While, Repeat, End, Pause, Lbl, Goto, Menu, Return, Stop, DelVar, Ans
Test	=, ≠, ≥, <, ≤
Logic	and, or, xor, not(
I/O	Input, Disp, Output(, getKey, ClrHome, Menu, Pause
Matrices	dim(, Fill(, augment(, cumSum(
List	dim(, Fill(, augment(, cumSum(, ClrList, ClrAllLists, SortA(, SortD(, seq(, ΔList(, min(, max(, sum(
Number	abs(, round(, iPart(, fPart(, int(, min(, max(
String	sub(, inString(
Probability	rand, randInt(
Math	cos(, cos⁻¹(, cosh(, cosh⁻¹(, sin(, sinh(, sin⁻¹(, sinh⁻¹(, tan(, tan⁻¹(, tanh(, tanh⁻¹(, ln(, log(, √(, ³√(, ᴇ

Possible Improvements

• Eliminate the Scanner#NormalizeSource function, which currently exists to support the DelVar optimization and the optional colon at the beginning of new lines. This logic should be integrated directly into the Scanner and Parser rather than handled by a utility function.
• Numbers are currently converted into a custom struct named TiNumber, which leads to excessive allocations and garbage generation.

Resources

• Crafting Interpreters by @munificent
• Let's Build A Simple Interpreter by @rspivak
  • Used to learn to write an interpreter, very interesting stuff!
• TI-Basic Developer
  • Used to get hardware and software specs
• TI 84 Calculator Online
  • Used to compare my interpreter with a complete emulator
• Texas Instruments TI-83 Manual Book