Skip to content
☕️ A boolean expression parser and evaluator in Elixir.
Elixir Erlang
Branch: master
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Type Name Latest commit message Commit time
Failed to load latest commit information.
config
lib handle invalid expressions Nov 21, 2018
src update grammar to support eq comparison on boolean types Feb 2, 2018
test
.gitignore
.travis.yml
LICENSE
README.md
mix.exs
mix.lock

README.md

Expreso Build Status Hex Version

An Elixir library for parsing and evaluating boolean expressions

Installation

From Hex, the package can be installed by adding it to your list of dependencies in mix.exs:

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}
You can’t perform that action at this time.