Ruby

Lua is a powerful, efficient, lightweight, embeddable scripting language. It supports procedural programming, object-oriented programming, functional programming, data-driven programming, and data description. Lua combines simple procedural syntax with powerful data description constructs based on associative arrays and extensible semantics. Lua is dynamically typed, runs by interpreting bytecode with a register-based virtual machine, and has automatic memory management with incremental garbage collection, making it ideal for configuration, scripting, and rapid prototyping. Lua has a deserved reputation for performance. To claim to be "as fast as Lua" is an aspiration of other scripting languages. Several benchmarks show Lua as the fastest language in the realm of interpreted scripting languages. Lua is fast not only in fine-tuned benchmark programs, but in real life too. Substantial fractions of large applications have been written in Lua.

Sinatra includes a number of built-in settings that control whether certain features are enabled. Settings are application-level variables that are modified using one of the set, enable, or disable methods and are available within the request context via the settings object. Applications are free to set custom settings as well as the default, built-in settings provided by the framework. In its simplest form, the set method takes a setting name and value and creates an attribute on the application. Extensions provide helper or class methods for Sinatra applications. These methods are customarily listed and described on extensions home pages. Using an extension is usually as simple as installing a gem or library and requiring a file.