{{language |site=http://fexl.com}} [http://fexl.com Fexl] is a [[functional programming]] language designed to be compact, efficient, and customizable in embedded environments. Its implementation aims to be the thinnest possible functional programming layer built on top of [[C]].

Fexl has no keywords, so whenever you see a symbol in a Fexl program, that symbol always refers to a function.

A symbol may be defined within a Fexl program, or its definition may be left entirely open. The definitions of all open symbols are supplied by a ''context''. A context is a function which supplies definitions for symbols. A context function is itself written in Fexl.

A Fexl program may therefore be resolved inside an arbitrary context, giving whatever meanings you like to all its open symbols. This makes it easy to wrap a Fexl program in an enhanced or restricted context. For example, in a web context you probably don't want "delete_file" to be defined at all, at least not in its normal sense. So you would resolve the program in a highly restricted context which only provides a handful of safe functions, omitting all the dangerous ones.