nerdypepper / eva

a calculator REPL, similar to bc(1)

eva

simple calculator REPL, similar to bc(1), with syntax highlighting and persistent history

installation

• Homebrew

$ brew install eva

• crates.io

$ cargo install eva

• manual

$ git clone https://github.com/nerdypepper/eva
$ cd eva
$ cargo run

usage

eva 0.3.1
NerdyPepper <[e-mail]>
Calculator REPL similar to bc(1)

USAGE:
    eva [OPTIONS] [INPUT]

ARGS:
    <INPUT>    Optional expression string to run eva in command mode

OPTIONS:
    -b, --base <RADIX>    Radix of calculation output (1 - 36) [default: 10]
    -f, --fix <FIX>       Number of decimal places in output (1 - 64) [default: 10]
    -h, --help            Print help information
    -r, --radian          Use radian mode
    -V, --version         Print version information

type out an expression and hit enter, repeat.

> 1 + sin(30)
1.5
> floor(sqrt(3^2 + 5^2))
5
> 5sin(45) + cos(0)
4.53553

updating

• crates.io

$ cargo install eva --force

• manual

$ cargo install --force --path /path/to/eva

operators

• binary operators: + - * / ^ **
• unary operators: + -

constants

some constants available in rust standard library.

e      pi

examples:

pi * 5^2  # πr²

functions

all trigonometric functions expect input in degrees.

1 argument:
sin    cos     tan    csc    sec    cot    sinh   cosh   tanh
asin   acos    atan   acsc   asec   acot   ln     log2   log10
sqrt   ceil    floor  abs

2 arguments:
log    nroot

deg(x) - convert x to degrees
rad(x) - convert x to radians

examples:

sqrt(sin(30)) # parentheses are mandatory for functions

log10100      # no
log10(100)    # yes

log(1, 10)    # function with two arguments

quality of life features

• auto insertion of * operator

>12sin(45(2))             # 12 * sin(45 * (2))
12

• auto balancing of parentheses

>ceil(sqrt(3^2 + 5^2      # ceil(sqrt(3^2 + 5^2))
6

• use previous answer with _

> sin(pi)
0.0548036650
> _^2
0.0030034417
>

• super neat error handling

> 1 + ln(-1)
Domain Error: Out of bounds!

• syntax highlighting

todo

• add support for variables (pi, e, _ (previous answer))
• syntax highlighting
• multiple arg functions
• screenshots
• create logo
• unary operators (minus, plus)
• add detailed error handler
• add unit tests
• lineditor with syntax highlighting
• add more functions

contributors

the rust community has helped eva come a long way, but these devs deserve a special mention for their contributions:

Ivan Tham
Milan Marković
asapokl