Overview of features
    Operators: +, -, *, /, !, %
    Groups: (), ⌈⌉, ⌋⌊
    Pre-defined functions and constants
    User-defined functions and variables
    User-defined units (experimental)
    Understands fairly ambiguous syntax. Eg. 2sin50 + 2xy
    Syntax highlighting
    Completion for special symbols on tab
    Sum functions

Operators
    +, -, *, /
    ! Factorial, eg. 5! gives 120
    % Percent, eg. 5% gives 0.05, 10 + 50% gives 15
    % Modulus (remainder), eg. 23 % 3 gives 2

Completion for special symbols
    You can type special symbols (such as √) by typing the normal function or constant name and pressing tab.

    sqrt becomes √
    deg becomes °
    pi becomes π
    sum becomes Σ()
    tau becomes τ
    phi becomes ϕ
    floor becomes ⌊⌋
    ceil becomes ⌈⌉
    gamma becomes Γ
    ( becomes ()

Variables
Variables are defined with the following syntax: name = value
Example: x = 3/4

Functions
Functions are defined with the following syntax: name(param1, param2, etc.) = value
Examples: f(x) = 2x+3; A(x, y) = (xy)/2
They are used like this: name(arg1, arg2, etc.)
Example: f(3) + 3 A(2, 3) 

Predefined functions
    sin, cos, tan, cot, csc, sec
    sinh, cosh, tanh, coth, csch, sech
    asin, acos, atan, acot, acsc, asec
    asinh, acosh, atanh, acoth, acsch, asech
    abs, ceil or ⌈⌉, floor or ⌊⌋, frac, round, trunc
    sqrt or √, cbrt, exp, log, ln
    gamma or Γ
    asinh, acosh, atanh, acoth, acsch, asech
    min, max, hyp
    log Eg. log(1000, 10) is the same as log10(1000)
    root Eg. root(16, 3) is the same as 3√16
    sum Eg. sum(1, 4, 2n), example below

Sum function
    The sum function lets you sum an expression with an incrementing variable.
    It takes three arguments: start value, end value, and expression.
    If you press tab after typing out "sum", it will be replaced with a sigma symbol.
    The expression is what will be summed, and will be able to use the "n" variable,
    which represents the current value between the start value and the end value.
    The value of "n" increments.
    Example: sum(1, 4, 2n) will be the same as 2*1 + 2*2 + 2*3 + 2*4 = 20
    This can for example be used to calculate e: Σ(0, 10000, 1/n!) = 2.7182818284590455
    More precision can be gotten by changing the "--precision" flag. Run `kalk --help` for more info.

Constants
    pi or π = 3.14159265
    e = 2.71828182
    tau or τ = 6.2831853
    phi or ϕ = 1.61803398