ympons / expreso

:coffee: A boolean expression parser and evaluator in Elixir.

Expreso

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}