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Diffstat (limited to 'Master/texmf-dist/doc/latex/stex/packages/stex-inheritance.tex')
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diff --git a/Master/texmf-dist/doc/latex/stex/packages/stex-inheritance.tex b/Master/texmf-dist/doc/latex/stex/packages/stex-inheritance.tex index 41631f94d27..be7c4e68ec0 100644 --- a/Master/texmf-dist/doc/latex/stex/packages/stex-inheritance.tex +++ b/Master/texmf-dist/doc/latex/stex/packages/stex-inheritance.tex @@ -1 +1,131 @@ -\textcolor{red}{TODO: inheritance documentation}
\ No newline at end of file +\begin{sfragment}{Simple Inheritance and Namespaces} + + \begin{function}{\importmodule,\usemodule} + \stexcode"\importmodule[Some/Archive]{path?ModuleName}" is only allowed within an + \stexcode"smodule"-environment and makes the symbols declared in |ModuleName| + available therein. Additionally the symbols of |ModuleName| will be exported if the + current module is imported somewhere else via \stexcode"\importmodule". + + \stexcode"\usemodule" behaves the same way, but without exporting the content of the + used module. + \end{function} + + It is worth going into some detail how exactly \stexcode"\importmodule" + and \stexcode"\usemodule" resolve their arguments to find + the desired module -- which is closely related to the + \emph{namespace} generated for a module, that is used to generate + its URI. + + \begin{dangerbox} + Ideally, \sTeX would use arbitrary URIs for modules, with no + forced relationships between the \emph{logical} namespace + of a module and the \emph{physical} location of the file + declaring the module -- like \mmt does things. + + Unfortunately, \TeX\ only provides very restricted access to + the file system, so we are forced to generate namespaces + systematically in such a way that they reflect the physical + location of the associated files, so that \sTeX can resolve + them accordingly. Largely, users need not concern themselves + with namespaces at all, but for completenesses sake, we describe + how they are constructed: + + \begin{itemize} + \item If \stexcode"\begin{smodule}{Foo}" + \iffalse\end{smodule}\fi occurs in a file + |/path/to/file/Foo[.|\meta{lang}|].tex| which does not belong + to an archive, the namespace is |file://path/to/file|. + \item If the same statement occurs in a file + |/path/to/file/bar[.|\meta{lang}|].tex|, the namespace is + |file://path/to/file/bar|. + \end{itemize} + + In other words: outside of archives, the namespace corresponds to + the file URI with the filename dropped iff it is equal to the + module name, and ignoring the (optional) language suffix. + + If the current file is in an archive, the procedure is the same + except that the initial segment of the file path up to the archive's + |source|-folder is replaced by the archive's namespace URI. +\end{dangerbox} + +\begin{dangerbox} + Conversely, here is how namespaces/URIs and file paths are computed + in import statements, examplary \stexcode"\importmodule": + + \begin{itemize} + \item \stexcode"\importmodule{Foo}" outside of an archive refers + to module |Foo| in the current namespace. Consequently, |Foo| + must have been declared earlier in the same document or, if not, + in a file |Foo[.|\meta{lang}|].tex| in the same directory. + \item The same statement \emph{within} an archive refers to either + the module |Foo| declared earlier in the same document, or + otherwise to the module |Foo| in the archive's top-level namespace. + In the latter case, is has to be declared in a file |Foo[.|\meta{lang}|].tex| + directly in the archive's |source|-folder. + \item Similarly, in \stexcode"\importmodule{some/path?Foo}" the path + |some/path| refers to either the sub-directory and relative + namespace path of the current directory and namespace outside of an archive, + or relative to the current archive's top-level namespace and |source|-folder, + respectively. + + The module |Foo| must either be declared in the file + \meta{top-directory}|/some/path/Foo[.|\meta{lang}|].tex|, or in + \meta{top-directory}|/some/path[.|\meta{lang}|].tex| (which are + checked in that order). + \item Similarly, \stexcode"\importmodule[Some/Archive]{some/path?Foo}" + is resolved like the previous cases, but relative to the archive + |Some/Archive| in the mathhub-directory. + \item Finally, \stexcode"\importmodule{full://uri?Foo}" naturally refers to the + module |Foo| in the namespace |full://uri|. Since the file this module + is declared in can not be determined directly from the URI, the module + must be in memory already, e.g. by being referenced earlier in the + same document. + + Since this is less compatible with a modular development, using full + URIs directly is strongly discouraged, unless the module is delared in + the current file directly. + \end{itemize} + + \end{dangerbox} + + \begin{function}{\STEXexport} + \stexcode"\importmodule" and \stexcode"\usemodule" import all symbols, notations, + semantic macros and (recursively) \stexcode"\importmodule"s. If you want to + additionally export e.g. convenience macros and other (\sTeX) code from a module, you + can use the command \stexcode"\STEXexport{<code>}" in your module. Then |<code>| is + executed (both immediately and) every time the current module is opened via + \stexcode"\importmodule" or \stexcode"\usemodule". + \end{function} + + \begin{dangerbox} + For persistency reasons, everything in an \stexcode"\STEXexport" + is digested by \TeX in the \LaTeX3-category code scheme. + This means that the characters \stexcode"_" and \stexcode":" + are considered \emph{letters} and valid parts of + control sequence names, and space characters are ignored entirely. + For spaces, use the character \stexcode"~" instead, and + keep in mind, that if you want to use subscripts, you + should use \stexcode"\c_math_subscript_token" instead + of \stexcode"_"! + + + Also note, that \stexcode"\newcommand" defines macros \emph{globally} + and throws an error if the macro already exists, + potentially leading to low-level \LaTeX\xspace errors if + we put a \stexcode"\newcommand" in an \stexcode"\STEXexport" + and the |<code>| is executed more than once in a document + -- which can happen easily. + + A safer alternative is to use macro definition principles, + that are safe to use even if the macro being defined already + exists, and ideally are local to the current \TeX\xspace group, + such as \stexcode"\def" or \stexcode"\let". + \end{dangerbox} + +\end{sfragment} + +%%% Local Variables: +%%% mode: latex +%%% TeX-master: "../stex-manual" +%%% End: |