Links: Linking Theory to Practice for the Web

Links is a new programming language designed to make web programming easier.

Links eases building modern Ajax-style applications: those with significant client- and server-side components.

A typical, modern web program involves many "tiers": part of the program runs in the web browser, part runs on a web server, and part runs in back-end systems such as a relational database. To create such a program, the programmer must master a myriad of languages: the logic is written in a mixture of Java, Python, and Perl; the presentation in HTML; the GUI behavior in Javascript; and the queries are written in SQL or XQuery. There is no easy way to link these, for example, to be sure that an HTML form or an SQL query produces the type of data that the Java code expects. This problem is called the impedance mismatch problem.

Links eases the impedance mismatch problem by providing a single language for all three tiers. The system generates code for each tier; for instance, translating some code into Javascript for the browser, some into a bytecode for the server, and some into SQL for the database.

Links incorporates proven ideas from other programming languages: database-query support from Kleisli, web-interaction proposals from PLT Scheme, and distributed-computing support from Erlang. On top of this, it adds some new web-centric features of its own.


Demo Links programs.


Version 0.5 of Links must be compiled with OCaml version 3.10 as there is a regression in the camlp4 tool shipped with later versions of OCaml. The latest version of Links in the Subversion respository includes a workaround for the camlp4 regression. It compiles with OCaml version 3.12, but probably won't compile with earlier versions.


links-users mailing list



Group photo (Nov 2006).

Undergraduate projects

MSc projects




(accessible only from Edinburgh).

Philip Wadler,
Last modified: Thu Feb 9 17:20:57 GMT 2012