TI-BASIC

An interpreter for a simplified version of the TI-BASIC language found on TI-83/84 graphing calculators. Some operators are modified so that they may be more easily written with ASCII characters.

How to Build

$ make

This will create the interpreter tibasic in the project root directory, and all the object files will be in the build directory. To clean up, just run make clean.

How to Install

$ sudo ./install.sh

This will run make then move the compiled binary to /usr/local/bin, and finally call make clean. If there is a compilation error, nothing should be copied to that directory.

How to Run

With the interpreter:

$ tibasic source_file

• source_file: Source file name

Without the interpreter: Include the shebang in the source_file.

Implementation

The language currently only supports a limited subset of the original TI-BASIC language. This includes the following list of commands, the following list of operators, A-Z and Ans real variables, not function, and real numbers.

Features

This implementation supports single line comments that begin with a #. Note that the line delimiter ':' will not end the comment, only a newline character '\n' will. A consequence of this is that shebangs can be supported. The following is an example of a comment.

#This is a comment

Shebangs

A shebang is a special comment on the first line of a program that tells the shell what interpreter to use to run the program. It looks like the following:

#!/usr/bin/env tibasic

The first part # denotes a comment, but paired with a ! denotes a shebang. The following is a full path to the interpreter with optional arguments to be supplied. What this is really doing is calling /usr/bin/env with tibasic as an argument. That in turn looks for tibasic in the $PATH and runs that.

The benefit of the shebang is that it lets you execute the program without you needing to specify the interpreter. You can simply execute the file like so:

$ ./source_file

Note however that you must first have the execution permission for the file set. You can do that like so:

$ chmod +x source_file

However this method of execution only works if you use the shebang, and the tibasic interpreter can be found on the $PATH.

Supported Commands

• If
• Then
• Else
• For
• While
• Repeat
• End
• Prompt
• Disp
• ClrHome

Supported Operators

• : : Line delimiter
• -> : Assignment
• () : Parentheses
• and: And
• or : Or
• xor: Xor
• = : Equal
• != : Not equal
• > : Greater than
• >= : Greater than or equal
• < : Less than
• <= : Less than or equal
• + : Addition
• - : Subtraction
• * : Multiplication
• / : Division
• ~ : Negation
• ^ : Exponentiation