© Jørgen Steensgaard-Madsen, Copenhagen, 2006
FigUp: generating Fig-files for Xfig                                                  

Xfig is a program that depends on a text representation of drawings. Humans are expected to create drawings using a graphical interface, not the text representation, known as Fig-files. Xfig is thus similar to WYSIWYG editors, and sometimes this is not appropriate: it will not be attractive to generate a blueprint for semi-logarithmic graph paper.
FigUp can be conceived as an extension to a programming language for generating Fig-files, presumably based on computations. Such extensions depend on a key feature of a family of languages called Howard languages. Each family member is a programming language characterised by its extensions to a core language with so few features that it hardly can be called a programming language. But the core implements the means that allows language extensions.
FigUp is used here as a vehicle to introduce extension mechanisms. Somebody once rebutted a presentation of these as being merely rules for calling subroutines in a special way. This is fully justified, but it applies to all programming languages in the sense that the syntax serves to express combination of semantic routines. Subroutines of Howard languages can certainly be considered as semantic routines. Predefined subroutines follow the same rules as internally defined ones, but typically implement irreducible aspects of a language, e.g. parallelism, input/output, binary operators, and branching.
Two students at Technical University of Denmark, Waqas Ashraf and Amit Luthra, wrote the first version of FigUp, named XfigCreator. It was written while tools to support Howard languages were being developed. FigUp has been modified to match the current status and a few mistakes have been corrected. The two students went on with their studies and have no responsibilities with the present version.


·Demo language
Implementation tool

General properties

Russian roulette
A heterogeneous system


File translated from TEX by TTH, version 3.33.
On 18 Oct 2006, 16:47.
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