# Package org.apache.lucene.expressions.js

Javascript expressions.

See: Description

- Class Summary
  Class | Description
  --- | ---
  JavascriptCompiler | An expression compiler for javascript expressions.
  VariableContext | A helper to parse the context of a variable name, which is the base variable, followed by the sequence of array (integer or string indexed) and member accesses.

- Enum Summary
  Enum | Description
  --- | ---
  VariableContext.Type | Represents what a piece of a variable does.

## Package org.apache.lucene.expressions.js Description

Javascript expressions.

A Javascript expression is a numeric expression specified using an expression syntax that's based on JavaScript expressions. You can construct expressions using:

- Integer, floating point, hex and octal literals
- Arithmetic operators: `+ - * / %`
- Bitwise operators: `| & ^ ~ << >> >>>`
- Boolean operators (including the ternary operator): `&& || ! ?:`
- Comparison operators: `< <= == >= >`
- Common mathematic functions: `abs ceil exp floor ln log10 logn max min sqrt pow`
- Trigonometric library functions: `acosh acos asinh asin atanh atan atan2 cosh cos sinh sin tanh tan`
- Distance functions: `haversin`
- Miscellaneous functions: `min, max`
- Arbitrary external variables - see `Bindings`

JavaScript order of precedence rules apply for operators. Shortcut evaluation is used for logical operators—the second argument is only evaluated if the value of the expression cannot be determined after evaluating the first argument. For example, in the expression `a || b`, `b` is only evaluated if a is not true.

To compile an expression, use `JavascriptCompiler`.

Copyright © 2000-2019 Apache Software Foundation. All Rights Reserved.