https://github.com/ympons/expreso

:coffee: A boolean expression parser and evaluator in Elixir.
https://github.com/ympons/expreso

boolean-expression elixir eval expreso lexer parser

Last synced: 3 months ago
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:coffee: A boolean expression parser and evaluator in Elixir.

• Host: GitHub
• URL: https://github.com/ympons/expreso
• Owner: ympons
• License: mit
• Created: 2017-02-02T08:09:19.000Z (about 8 years ago)
• Default Branch: master
• Last Pushed: 2020-01-22T04:48:16.000Z (about 5 years ago)
• Last Synced: 2024-10-31T18:26:59.037Z (3 months ago)
• Topics: boolean-expression, elixir, eval, expreso, lexer, parser
• Language: Elixir
• Homepage:
• Size: 22.5 KB
• Stars: 66
• Watchers: 8
• Forks: 4
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Expreso [![Build Status](https://travis-ci.org/ympons/expreso.svg?branch=master)](https://travis-ci.org/ympons/expreso) [![Hex Version](https://img.shields.io/hexpm/v/expreso.svg)](https://hex.pm/packages/expreso)

An Elixir library for parsing and evaluating boolean expressions

## Installation

From [Hex](https://hex.pm/packages/expreso), the package can be installed by adding it to your list of dependencies in `mix.exs`: 

```elixir

def deps do

  [{:expreso, "~> 0.1.1"}]

end

```

## Usage

```

Expreso.eval(expression, variables)

```

Parses and evaluates the provided expression. The variables can be supplied as a map in the `variables` parameter.

eg.

```

# Evaluate if a + 2 is between 3 and 1

iex> Expreso.eval("a + 2 in (3, 1)", %{"a" => 1})

iex> {:ok, true}

# Check if the key "test" is "works"

iex> Expreso.eval("test = 'works'", %{"test" => "works"})

iex> {:ok, true}

# Check if the key "test" is "works" or "great"

iex> Expreso.eval("test = 'works' or test = 'great'", %{"test" => "great"})

iex> {:ok, true}

# Evaluate an expression with not_in_op and sum

iex> Expreso.eval("10 + 2 not in (3, 1)")

iex> {:ok, true}

# Evaluate an expression with and_logic

iex> Expreso.eval("a + 2 in (2, 3) and 1 + 1 >= 2", %{"a" => 1})

iex> {:ok, true}

# Evaluate an expression with string

iex> Expreso.eval("a = 'Hello' and b != 'World' and 1 + 1 = 2", %{"a" => "Hello", "b" => ""})

iex> {:ok, true}

# Evaluate an expression with an array variable

iex> Expreso.eval("a in b", %{"a" => 1, "b" => [2, 1]})

iex> {:ok, true}

# Evaluate another expression with an array variable

iex> Expreso.eval("a not in b", %{"a" => 1, "b" => [2, 1]})

iex> {:ok, false}

# Evaluate an expression using not operator

iex> Expreso.eval("not 1 > 1 + a", %{"a" => 2})

iex> {:ok, true}

```