Minimal pascal compiler to x86-64 assembly (AT&T syntax).

Supported features

1. Types
   1. integer, boolean, char, real, string, text, array (must be in format: array[start..end] of type)
   2. built-in type conversion: ORD(), CHR()
2. Logic blocks
   1. if, if-else, for, while, repeat-until, begin-end
3. Literals
   1. characters and strings both enclosed in ''
   2. minimal support for scientific notation (example: epsilon := 1E-6)
4. Constants
   1. CONST block as well as some pre-defined constants like maxint, true, and false
5. Variables
6. Math
   1. all common operators
   2. built-in functions: SQR(), SQRT()
7. Built-in procedures
   1. READ(), READLN(), WRITE(), WRITELN()

Design choices

1. Semicolons separate statements rather than end them
2. Does not automatically initialize variables

Running

Compile with:

cargo run -- program.pas program.s
gcc program.s -o program -lm

Known issues

1. String input limited to 255 bytes
2. Doesn't sanitize strings, currently throws them into printf (ignored since I don't want to keep libc dependency)
3. Blatant syntax error reporting seems pretty solid but need a nice looking warning/error reporting for other errors
4. Error reporting for unrecognized identifiers just crashes program
5. Calloc's every time a string is read in and free's none of it (after dropping libc dependency I'll store strings a different way entirely)
6. Support for special characters like ≥ is poor and they should be avoided for now

Next planned features

1. Expand scientific notation to allow for decimal before E
2. Add more common math functions (ln, exp)
3. Implement number formatting using colons in write calls
4. Add procedures
5. Add functions