redcalc

A CLI calculator REPL written in Red, utilising the parse dialect (DSL) for expression parsing.

It should work, but has not been extensively tested.

Usage

To run the script, run make, supplying the path to the red interpreter executable (get here), e.g.:

make RED=<path_to_red>

Alternatively you can just run:

<path_to_red> src/main.red

This will start the redcalc REPL. To quit the REPL, enter "q" or use Ctrl+D/Ctrl+C on compatible terminals.

Docs

Calculations are expressions that are formed of numbers, operators and functions. Syntax should be fairly intuitive.

Note that redcalc is not capable of displaying fine-grained syntax errors - Currently, it only knows there was a syntax error, not why or where it originated.

>>> 12*-(2/3)
= -8.0
>>> -sin(21e3)/2
= -0.49985711969854346
>>> 15 * 3! / (2 - 8)
= -15.0
>>> 2 ^ -8
= 0.00390625
>>> 8 % 3 + 1
= 3.0
>>> sin(cos(tan(0)))
= 0.8414709848078965

Numbers

Numbers are 64-bit floating point, and can be expressed in scientific notation.

>>> 2
= 2.0
>>> 7.0154e10
= 70154000000.0

Operators

Operators are either infix (x + y), postfix (x!) or prefix (-x).

Precedence follows usual rules - Postfix/prefix operators have the highest precedence, followed by the infix operators in order: ^, then */%, then +-. Brackets can override precedence, as well as grouping expressions.

Infix operators:

Operator	Description
`+`	Addition
`-`	Subtraction
`*`	Multiplication
`/`	Division
`^`	Exponentiation
`%`	Modulus

Postfix operators:

Operator	Description
`!`	Factorial

Prefix operators:

Operator	Description
`-`	Negation

Functions

Functions currently can only have 1 argument, that is enclosed in brackets, e.g. sin(0).

Trigonometric functions assume radians are used.

Supported functions:

Function	Description
`sin`	Sine
`cos`	Cosine
`tan`	Tangent
`abs`	Absolute value