mirror of https://github.com/texmacs/doc.git
96 lines
4.0 KiB
Tcl
96 lines
4.0 KiB
Tcl
<TeXmacs|1.0.3.7>
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<style|tmdoc>
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<\body>
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<tmdoc-title|ASCII-based or tree-based editing: an intricate choice>
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Most users are used to edit source code using a conventional editor like
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<name|Emacs>, while presenting the source code in ASCII format. Since all
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<TeXmacs> documents are stored as <hyper-link|trees|../../format/format.en.tm>,
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an interesting but complicated question is which format is most suitable
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for editing such documents. One option is to represent the tree using an
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ASCII-based format, such as XML, Scheme, or the native format for storing
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files on a disk. The other option is to edit the trees as such, making no
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fundamental distinction between source code and normal documents.
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In <TeXmacs> we have chosen to implement the second option. More precisely,
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any document can be edited in ``source mode'', which is merely a mode for
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rendering the document in a way which makes its tree structure particularly
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apparent. It may be instructive to take an arbitrary document of yours and
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to take a look at it in ``source mode'' by enabling
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<menu|Document|View|Edit source tree>.
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The choice between ASCII-based editing and tree-based editing is
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non-trivial, because <TeXmacs> style files and packages have a double
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nature: they may be seen as programs which specify how to render macros,
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but these programs naturally contain ordinary content. There are several
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reasons why users often prefer to edit source code in an ASCII-based
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format:
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<\enumerate>
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<item>It is easy to manually format the code so as to make it more
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readable.
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<item>In particular, it is easy to add comments.
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<item>Standard editors like <name|Emacs> provide tools for automatic
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highlighting, indentation, <abbr|etc.>
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<item><label|structure-constraints>One is not constraint by any
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``structure'' during the editing phase.
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</enumerate>
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Our approach is to reproduce as much of the above advantages in a
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structured document environment. Although point
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<reference|structure-constraints> will obviously be hard to meet when
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following this approach, we believe that the first three advantages might
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actually become greater in a structured environment. However, this requires
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a more profound understanding of how users format and edit source code.
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For instance, consider a piece of manually formatted code like
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<\cpp-fragment>
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if (cond) hop \ \ = 2;
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else \ \ \ \ \ holala= 3;
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</cpp-fragment>
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Clearly, the user had a particular formatting policy when writing this
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code. However, this policy does not appear in the document: manual
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intervention will be necessary if the variable <verbatim|cond> is renamed
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<verbatim|c>, or if the variable <verbatim|holala> is renamed
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<verbatim|hola>.
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At the moment, <TeXmacs> provides no tools for dealing with the above
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example in an automatic way, but a few tools are already provided. For
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instance, the user is given a great amount of control on how to indent
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source code and reasonable defaults are provided as a function of the
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structure. We also provide high level environments for comments and
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structured highlighting. Further tools will be developed later and we are
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open for any suggestions from our users.
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<tmdoc-copyright|1998--2004|Joris van der Hoeven>
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<tmdoc-license|Permission is granted to copy, distribute and/or modify this
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document under the terms of the GNU Free Documentation License, Version 1.1
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or any later version published by the Free Software Foundation; with no
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Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
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Texts. A copy of the license is included in the section entitled "GNU Free
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Documentation License".>
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</body>
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<\initial>
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<\collection>
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<associate|page-bot|30mm>
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<associate|page-even|30mm>
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<associate|page-odd|30mm>
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<associate|page-reduce-bot|15mm>
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<associate|page-reduce-left|25mm>
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<associate|page-reduce-right|25mm>
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<associate|page-reduce-top|15mm>
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<associate|page-right|30mm>
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<associate|page-top|30mm>
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<associate|par-width|150mm>
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</collection>
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</initial> |