In this chapter we describe some more practical aspects of using LAML. We also touch on the XML-in-LAML approach.

28.1.  LAML document processing
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As one of the underlying ideas of LAML, we organize the programmatic source of a web document as a Scheme program. When the Scheme program is executed, the underlying HTML files are generated.

It is of practical importance to make it easy and flexible to execute the Scheme program. Below we summarize the possibilities supported in the LAML system.

Let us be more concrete. Scheme source files with LAML documents are supposed to have the file extension 'laml'. We will assume that we have written source document in a file called 'd.laml'.

From a command prompt or a Unix shell, you can execute it and hereby generate the underlying HTML file by the command laml d.

From a Scheme interpreter (a Scheme prompt) in which the basic LAML software has been loaded, you can type (laml "d") followed by "enter". This is a call of the laml procedure on "d".

From within Emacs (in which the LAML mode has been loaded) you can process a the document directly, by issuing the command M-x laml-process-current-buffer. (It is assumed, however, that the buffer is associated with a file at some location in the file system). The emacs command laml-process-current-buffer is bound to some convenient shortcut, C-o, which makes it very easy to do the processing.

In Emacs, it is possible to start an interactive Scheme/LAML session. This is done with M-x run-laml-interactively. Using this possibility, the Scheme system is started, and selected LAML libraries are loaded. The Emacs Lisp variables interactive-laml-mirror-library and interactive-laml-load-convenience-library control which HTML mirror library and which additional support libraries to load in the interactive LAML session.

As a practical remark, we will strongly recommend that LAML is used via Emacs. Authors of LAML-based materials should make use the features of the Emacs laml mode. Similarly, users who interact with the Scheme system can make good use of the additional support in Emacs, such as the run-laml-interactively command mentioned above, and the variables that control the behavior of this command.

28.2.  LAML document styles and tools
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The purpose of this section is to give a short overview of some of the major document styles and tools in LAML. A document style is a LAML based language. All such new languages are derived from an XML document type definition.

The overview below is by no means comprehensive. You are referred to the LAML Software home page [normark02e] for details.

28.3.  LAML server-side programming - CGI
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LAML can be used for authoring of static web material using a Scheme mirror of an XML language. LAML has also been used for server side programming using the Common Gateway Interface - CGI.

In this material we will not cover CGI programming in Scheme, but we will refer to an elucidative tutorial on the topic.

An example of CGI Programming in Scheme with LAML

IDAFUS - Insitut for DAtalogis FjernUndervisnings System - is a major example of a LAML server application used for non-trivial purposes during a number of years in open university educations. The exercise manager is a minor system for synchronous management of exercise sessions. It requires user name and password to try out these systems.

The LAML calendar manager is widely used at Aalborg University for course and semester calendar management. The author's (simple) calendar can be accessed as an example [kn-calendar]. From a given calendar you can create your own, if you want.

28.4.  XML in LAML
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XML-in-LAML is the LAML framework for mirroring of XML languages in Scheme.

In LAML there is a DTD parser, which produces a Lisp representation of a DTD. Based on this representation it is possible to synthesize an exact Scheme mirror of the XML language. The properties of this mirror is described below.

Currently we convert several existing LAML document styles to the XML-in-LAML framework. As an important language for this material - LENO has already been transformed.

28.5.  More information
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The LAML home page [laml-home] contains all the papers that have been written above LAML and LENO.

The aim of the LAML tutorial [laml-tutorial] is to introduce various aspects of LAML in a gentle way.

The LAML software home page [laml-software] contains an overview of all the software, and it gives access to a download page where the latest distribution is made available as free software.

The exercise below is seen as a typical, practically oriented example where LAML can be used for management of everyday information.