%% This is part of OpTeX project, see http://petr.olsak.net/optex \_codedecl \public {Prefixing and code syntax <2020-02-14>} % preloaded in format \_doc --------- All \TeX/ primitives have alternative control sequence `\_hbox` `\_string`, ... \_cod --------- \let\_directlua = \directlua \_directlua { % enable all TeX primitives with _ prefix tex.enableprimitives('_', tex.extraprimitives('tex')) % enable all primitives without prefixing tex.enableprimitives('', tex.extraprimitives()) % enable all primitives with _ prefix tex.enableprimitives('_', tex.extraprimitives()) } \_doc ------------------ \`\ea` is useful shortcut for `\expandafter`. We recommend to use always the private form of \`\_ea` because there is high probability that `\ea` will be redefined by the user. \nl \`\public` ` ... ;` does `\let \ = \_` for all sequences. \nl \`\private` ` ...;` does `\let \_ = \` for all sequences. \nl \`\xargs` ` ... ;` does `` for each sequences. \_cod ----------------- \_let\_ea =\_expandafter % usefull shortcut \_long\_def \_xargs #1#2{\_ifx #2;\_else \_ea#1\_ea#2\_ea\_xargs \_ea #1\_fi} \_def \_pkglabel{} \_def \_public {\_xargs \_publicA} \_def \_publicA #1{\_ea\_let \_ea#1\_csname \_pkglabel _\_csstring #1\_endcsname} \_def \_private {\_xargs \_privateA} \_def \_privateA #1{\_ea\_let \_csname \_pkglabel _\_csstring #1\_endcsname =#1} \_public \public \private \xargs \ea ; \_doc ----------------------- Each macro file should begin with \`\_codedecl` `\macro {}`. If the `\macro` is defined already then the `\endpinput` protects to read such file more than one times. Else the is printed to the terminal and the file is read.\nl The {\`\_endcode`} is defined as `\endinput` in the `optex.ini` file. \`\wterm` `{}` prints `` to the terminal and to the `.log` file (as in plain \TeX/). \_cod ----------------------- \_def \_codedecl #1#2{% \_ifx #1\_undefined \_wterm{#2}% \_else \_expandafter \_endinput \_fi } \_def \_wterm {\_immediate \_write16 } \_public \wterm ; \_doc ------------------------ The `\optexversion` and `\fmtname` are defined in the `optex.ini` file. Maybe, somebody will need a private version of these macros. \_cod ------------------------ \_private \optexversion \fmtname ; \_doc ----------------------------- The `\_mathsbon` and `\_mathsboff` are defined in `math-macros.opm` file. Now, we define the macro \`\_namespace` `{}` for package writers, see section~\ref[pkg-namespace]. \_cod ----------------------------- \_def\_namespace #1{% \_ifcsname namesp:#1\_endcsname \_errmessage {The name space "#1" is used already, it cannot be used twice}% \_endinput \_else \_ea \_gdef \_csname namesp:#1\_endcsname {}% \_gdef \_pkglabel{_#1}% \_directlua{ callback.register("process_input_buffer", function (str) return string.gsub(str, "\_nbb[.]([a-zA-Z])", "\_nbb _#1_\_pcent 1") end ) }% \_gdef \_endcode {% \_ifmathsb \_mathsbon \_else \_mthsboff \_fi \_gdef \_pkglabel{_#1}% \_global \_let \_endcode=\_endinput \_endinput }% \_fi } \_endcode %---------------------------------------------------- \sec Concept of name spaces of control sequences \secc Prefixing internal control sequences All control sequences used in \OpTeX/ are used and defined with `_` prefix. The user can be sure that when he/she does `\def\foo` then internal macros of \OpTeX/ nor \TeX/ primitives will be not damaged. For example `\def\if{...}` will not damage macros because \OpTeX/'s macros are using `\_if` instead of `\if`. All \TeX/ primitives are initialized with two representative control sequences: `\word` and `\_word`, for example `\hbox` and `\_hbox`. The first alternative is reserved for users or such control sequences can be re-defined by user. \OpTeX/ sets the character `_` as letter, so it can be used in control sequences. When a control sequence begins with this character then it means that it is a primitive or it is used in \OpTeX/ macros as internal. User can redefine such prefixed control sequence only if he/she explicitly know what happens. We never change catcode of `_`, so internal macros can be redefined by user without problems if it is desired. We need not something like `\makealetter` from \LaTeX/. \OpTeX/ defines all new macros as prefixed. For public usage of such macros we need to set non-prefixed version. This is done by \begtt \public ; \endtt For example \^`\public`` \foo \bar ;` does `\let\foo=\_foo`, `\let\bar=\_bar`. At the end of each code segment in \OpTeX/, the `\_public` macro is used. You can see, what macros are defined for public usage in such code segment. The macro \^`\private` does a reverse job to `\public` with the same syntax. For example `\private \foo \bar ;` does `\let\_foo=\foo`, `\let\_bar=\bar`. This should be used when unprefixed variant of control sequence is declared already but we need the prefixed variant too. In this documentation: if both variants of a control sequence are declared (prefixed and unprefixed), then the accompanying text mentions only unprefixed variant. The code typically defines prefixed variant and then the \^`\public` (or `\_public`) macro is used. \secc Name space of control sequences for users User can define or declare any control sequence with a name without any `_`. This does not make any problem. Only one exception is the reserved control sequence `\par`. It is generated by tokenizer (at empty lines) and used as internal in \TeX/. User can define or declare control sequences with `_` character, for example `\my_control_sequence`, but with the following exceptions: \begitems * Control sequences which begin with `_` are reserved for \TeX/ primitives, \OpTeX/ internal macros and macro package writers. * Control sequences (terminated by non-letter) in the form `\_` or `\_`, where is a sequence of letters, are unaccessible, because they are interpreted as `\` followed by `_` or as `\` followed by `_`. This is important for writing math, for example: \begtt \adef-{_} \int-a^b ... is interpreted as \int _a^b \max-M ... is interpreted as \max _M \alpha-{ij} ... is interpreted as \alpha _{ij} \endtt This feature is implemented using lua code at input processor level, see the section~\ref[math-macros] for more details. You can deactivate this feature by \^`\mathsboff`. After this, you can still write `$`$\int$`_a^b$` (Unicode) or `$\int _a^b$` % $∫_a^b$ (Unicode) or $\int _a^b$ without problems but `\int``_a^b` yields to undefined control sequence `\int``_a`. You can activate this feature again by \^`\mathsbon`. The effect will take shape from next line read from input file. * Control sequences in the form `\__` is intended for package writers as internal macros for a package with `` identifier, see section~\ref[pkg-namespace]. \enditems The single letter control sequences like `\%`, `\$`, `\^` etc. are not used in internal macros. User can redefine them, but (of course) some classical features can be lost (printing percent character by `\%` for example). \secc Macro files syntax Each segment of \OpTeX/ macros is stored in one file with `.opm` extension (means OPtex Macros). Your local macros should be in normal `*.tex` file. The code in macro files starts by \^`\_codedecl` and ends by \^`\_endcode`. The \^`\_endcode` is equivalent for `\endinput`, so documentation can follow. The \^`\_codedecl` has syntax: \begtt \_codedecl \sequence {Name } \endtt If the mentioned `\sequence` is defined, then \^`\_codedecl` does the same as `\endinput`: this protect from reading the file twice. We suppose, that `\sequence` is defined in the macro file. It is possible to use the \^`\_doc` ... \^`\_cod` pair between the macro lines. The documentation text should be here. It is ignored when macros are read but it can be printed using `doc.opm` macros like in this documentation. \secc[pkg-namespace] Name spaces for package writers Package writer should use internal names in the form `\__`, where `` is a package label. For example: `\_qr_utfstring` from `qrcode.opm` package. The package writer needs not write repeatedly `\_pkg_foo` `\_pkg_bar` etc.\ again and again in the macro file.\fnote {We have not adatped the idea from expl3 language:)} When the \^`\_namespace` `{}` is declared at the beginning of the macro file then all occurrences of `\.foo` will be replaced by `\__foo` at the input processor level. The macro writer can write (and backward can read his/her code) simply with `\.foo`, `\.bar` control sequences and `\__foo`, `\__bar` control sequences are processed internally. The scope of the \^`\_namespace` command ends at the \^`\_endcode` command or when another \^`\_namespace` is used. This command checks if the same package label is not declared by the \^`\_namespace` twice. The \^`\public` macro does `\let\foo = \__foo` when \^`\_namespace{}` is declared. And the \^`\private` macro does reverse operation to it. Example: you can define `\def\.macro{...}` and then set it to the user name space by `\_public \macro;`. If the package writer needs to declare a control sequence by \^`\newif`, then there is an exception of the rule described above. Use \^`\_newifi\_if_bar`, for example `\_newifi\_ifqr_incorner`. Then the control sequences `\_qr_incornertrue` and `\_qr_incornerfalse` can be used (or the sequences `\.incornertrue` and `\.incornerfalse` when `\_namespace{qr}` is used). \secc Summary about rules for external macro files published for \OpTeX/ If you are writting a macro file which is intended to be published for \OpTeX/, then you are greatly welcome. You should follow these rules: \begitems * Don't use a control sequences from user name space in the macro bodies if there is not explicit and documented reason to do this. * Don't declare control sequences in the user name space if there is not explicit and documented reason to do this. * Use control sequences from \OpTeX/ and primitive name space in read only mode if there is not explicit and documented reason to redefine them. * Use `\__` for your internal macros or `\.` if the \^`\_namespace{}` is declared. See section~\ref[pkg-namespace]. * Use \^`\load` (or better: `\_load`) for loading more external macros if you need them. Don't use `\_input` explicitly in such cases. The reason is: the external macro file is not loaded twice if another macro or the user needs it explicitly too. * Use \^`\_codedecl` as your first command in the macro file and \^`\_endcode` to close the text of macros. * Use \^`\_doc` ... \^`\_cod` pairs for documenting the code pieces and/or write more documentation after the \^`\_endcode` command. \enditems If the macro file accepts these recommendations then it should be named by `.opm` where `` differs from file names used directly in \OpTeX/ and from other published macros. This extension `opm` has a precedence before `.tex` when the \^`\load` macro is used. The `qrcode.opm` is first example how an external macro file for \OpTeX/ can look like.