Lambda the Ultimate

Realization of natural language interfaces using lazy functional programming, Richard Frost, ACM Computing Surveys, Volume 38, Issue 4 (2006).

The construction of natural language interfaces to computers continues to be a major challenge. The need for such interfaces is growing now that speech recognition technology is becoming more readily available, and people cannot speak those computer-oriented formal languages that are frequently used to interact with computer applications. Much of the research related to the design and implementation of natural language interfaces has involved the use of high-level declarative programming languages. This is to be expected as the task is extremely difficult, involving syntactic and semantic analysis of potentially ambiguous input. The use of LISP and Prolog in this area is well documented. However, research involving the relatively new lazy functional programming paradigm is less well known. This paper provides a comprehensive survey of that research.

Apache Camel is a powerful rule based routing and mediation engine which provides a POJO based implementation of the Enterprise Integration Patterns using an extremely powerful fluent API (or declarative Java Domain Specific Language) to configure routing and mediation rules.

The authors probably meant embedded DSL. The examples of its use feel remarkably similar to "criteria queries" DSLs, as popularized in Java by Hibernate (and yes, many others as well).

To start a discussion - where is the boundary between an API and an embedded DSL? Is it in the eye of beholder or are there some objective differences? Some APIs have a strong feel of a DSL - remarkably various parser libraries in Haskell. Is it the quality of the host language (Haskell) or the domain (parsers)?