Leda is a multiparadigm programming language. The idea of a multiparadigm language is to provide a framework in which programmers can work in a variety of styles, freely intermixing constructs from different paradigms. The techniques supported by Leda include imparative programming, the object-oriented approach, logic programming, and functional programming.
A complete description of Leda can be found in the book, Multiparadigm Programming in Leda, published by Addison-Wesley 1995. Unfortunately, the book is now out of print, however, sample chapters from this book are available on-line; these include an introduction to the Leda language and a formal description of the Leda grammar.
A Belorussian translation of this page can be found here.