WWWeasel is written in WINTERP, the OSF/Motif Widget INTERPreter. WINTERP provides a high-level, portable, object-oriented rapid prototyping environment that significantly simplifies the creation of GUI-based applications. WINTERP also provides a basis for allowing end-user or system-integrator extensions to WWWeasel. WINTERP is written in XLISP-PLUS, an object-oriented mini-lisp interpreter with significant high-level GUI application functionality implemented directly in C for efficiency and for relatively small runtime size. Similarly architected mini-lisp-extensible applications include SoftQuad's SGML editor programming interface, GNU Emacs Lisp, and the AutoLisp extension language for AutoCAD.
Extensibility enables the creation of project-specific document templates, and HTML fill-in ``macros,'' which are useful for creating task-specific Internet publishing styles. The set of markup objects may be extended with ``active markup objects'' which may access other programs (e.g. databases, spreadsheets, etc.) to dynamically compute and format data for inclusion in an HTML document at the time the document is published.
The authoring environment's extensibility simplifies the integration of new task- or manufacturer- specific media types, media converters, and document format converters into a delivered system. WINTERP provides an asynchronous subprocess facility which is used to perform media capture and conversion as a background process. By using system-supplied or 3rd-party media capture/conversion programs, portability across different platforms is facilitated, and media extensions are easier to develop.