computor

Turing complete calculator built in haskell using a small parser combinator library

Dependencies

• readline (readline-devel)

Usage

stack build
stack run help                          # help
stack run poly "3X + 2X^2 = 4"          # solve polynomial
stack run poly "X^2 + 2X + 2 = 0"
stack run repl help                     # help
stack run repl nopreset                 # skip loading preset function/var definitions
stack run repl example/example1.txt     # load specified file

REPL

Data types
Int	5 -20
Float	3.5
Complex	6.2i 1i -3i
Matrix	[[1, 2]; [3, 4]] [[1.3, 2i]; [3 + 2i, -4.3 - 2.2i]]

Commands/Operators
@help	help msg
@quit	quit
@dump	show all defined variables/functions
@reset	clear all definitions
@poly X^2 + 2X = 7	evaluate polynomial
1 ^ 2 3i ^ 2	exponent
[[1,2]] ** [[3];[4]]	matrix multiplication
9 * 4	multiplication
8 / 2.8	division
11 % 6	mod (integers only)
4.2i + 2	addition
5 - 2	subtraction
4 < 5	lt
5 > 4	gt
2 == 2	eq
1 <= 8	leq
8 >= 3	geq
0 || 1	or
1 && 1	and
a = 42	assignment
f(a) = a * 2 f(a,b,c) = a+b+c	function definition
{1==1} (1) (0) min(a,b) = {a < b} a b	conditional

Resources

• parsing tutorial - Quick tutorial for writing a Scheme parser using Parsec
• Parsing.hs - Linked in this helpful computerphile video about parsing in Haskell

Tools

• hlint - powerful linter hlint src/ app/
• brittany - code formatter
• stack - project manager