------------------------------ GUIDELINES FOR ZSH DEVELOPMENT ------------------------------ Zsh is currently developed and maintained by the Zsh Development Group. This development takes place by mailing list. Check the META-FAQ for the various zsh mailing lists and how to subscribe to them. The development is very open and anyone is welcomed and encouraged to join and contribute. Because zsh is a very large package whose development can sometimes be very rapid, we kindly ask that people observe a few guidelines when contributing patches and feedback to the mailing list. These guidelines are very simple and hopefully should make for a more orderly development of zsh. Tools ----- To develop (as opposed to just build) zsh, you'll need a few specialised tools: * GNU autoconf, version 2.50 or later. This version contained significant enhancements and earlier versions will no longer work. * GNU m4. (Required by autoconf.) * yodl. * texi2html. Patches ------- * Send all patches to the mailing list rather than directly to me. * Send only context diffs "diff -c oldfile newfile" or unified diffs "diff -u oldfile newfile". They are much easier to read and understand while also allowing the patch program to patch more intelligently. Please make sure the filenames in the diff header are relative to the top-level directory of the zsh distribution; for example, it should say "Src/init.c" rather than "init.c" or "zsh/Src/init.c". Git-style naming of diffs is also acceptable. * Please put only one bug fix or feature enhancement in a single patch and only one patch per mail message. This helps me to multiplex the many (possibly conflicting) patches that I receive for zsh. You shouldn't needlessly split patches, but send them in the smallest LOGICAL unit. * If a patch depends on other patches, then please say so. Also please mention what version of zsh this patch is for. * Please test your patch and make sure it applies cleanly. It takes considerably more time to manually merge a patch into the baseline code. * By convention, patches should be sent with a Subject: line starting with one of "PATCH:", "[PATCH]" or "[PATCH n/m]" (for a patch series). Git Workflow ------------ Zsh has migrated from CVS to git for version control. Thus far, we have avoided further changes to our workflow. * To allow changesets to be cross-referenced between the mailing list archives and version control history, commit messages should start with the mailing list sequence number. This number is generated by the list server and inserted as an X-Seq: header field in the e-mail. * An entry in the ChangeLog file should be added manually before pushing a commit to the master repository. Don't create a separate change for this: amend the existing commit in your local repository. * Do not merge your private feature branches onto the master branch: a linear history without merge commits is simpler to follow (and to bisect). Use of Git ---------- Micro Git Tutorial: % $VISUAL file1.c file2.c new-file3.c % git add new-file3.c % git commit -a % git pull --rebase % git push "git commit -a" automatically finds files which are tracked and have been modified, but doesn't pick up new files; "git add" adds a file to the index to be part of the next commit, and can be used for new files or for existing files (commit -a is a shortcut for the latter) "git pull --rebase" ensures your local branch is up to date, needed before pushing; the "--rebase" option means that any changes in files also modified by you are handled by replaying your changes onto the remote ones, which avoids any unnecessary merges in the resulting history. "git push" assumes that you're on the master branch and the repository was created by cloning it from some place, with default options. Using a Local Feature Branch: % git checkout -b feature_foo % $VISUAL path/to/files ... % git commit -a [ generate single patch for changes ] % git diff master [ do mailing-list stuff here ] [ Switch back to master: ] % git checkout master [ and get the most recent changes: ] % git pull [ make the branch content now be relative to *new* master tip ] % git checkout feature_foo % git rebase master [ then bring in your changes: ] % git checkout master % git merge --squash feature_foo % $VISUAL ChangeLog % git add ChangeLog % git commit --amend % git push [ cleanup ] % git branch -d feature_foo The above assumes you want all your changes on the feature branch to be seen as a single change publicly. The normal git way to generate patches is to use git format-patch which produces separate patches already prepared for e-mailing. If you want to keep changes separate, don't use the --squash option to git merge. In this case, it can be wise to use --ff-only which ensures that you don't get a merge commit by only doing the merge if the master can be trivially moved forward. An alternative is to use git cherry-pick to pick out individual changes. Git further reading: * git help tutorial * git help tutorial-2 * git help gitcore-tutorial * http://www-cs-students.stanford.edu/~blynn/gitmagic/ Testing ------- * Because zsh has a huge number of different options and interacts with a wide range of human and artificial life, it is very difficult to test the shell thoroughly. For this purpose, the Test subdirectory exists. It consists of a driver script (ztst.zsh) and various test files (*.ztst) in a format which is described in B01cd.ztst, which acts as a template. It is designed to make it easy to provide input to chunks of shell code and to test the corresponding standard output, error output and exit status. * There is not much there yet, but please don't let that put you off adding tests for basic syntactic features, builtins, options etc. which you know to be flakey or to have had difficulties in the past. Better support for testing job control and interactive features is expected to follow eventually. * The directory is not part of the usual process of building and installation. To run the tests, go to Test and `make check'. Please report any errors with all the usual information about the zsh version and the system you are using. C coding style -------------- * The primary language is ANSI C as defined by the 1989 standard, but the code should always be compatible with late K&R era compilers ("The C Programming Language" 1st edition, plus "void" and "enum"). There are many hacks to avoid the need to actually restrict the code to K&R C -- check out the configure tests -- but always bear the compatibility requirements in mind. In particular, preprocessing directives must have the "#" unindented, and string pasting is not available. * Conversely, there are preprocessor macros to provide safe access to some language features not present in pure ANSI C, such as variable-length arrays. Always use the macros if you want to use these facilities. * Avoid writing code that generates warnings under gcc with the default options set by the configure script. For example, write "if ((foo = bar))" rather than "if (foo = bar)". * Please try not using lines longer than 79 characters. * The indent/brace style is Kernighan and Ritchie with 4 characters indentations (with leading tab characters replacing sequences of 8 spaces). This means that the opening brace is the last character in the line of the if/while/for/do statement and the closing brace has its own line: if (foo) { do that } * Put only one simple statement on a line. The body of an if/while/for/do statement has its own line with 4 characters indentation even if there are no braces. * Do not use space between the function name and the opening parenthesis. Use space after if/for/while. Use space after type casts. * Do not use (unsigned char) casts since some compilers do not handle them properly. Use the provided STOUC(X) macro instead. * If you use emacs 19.30 or newer you can put the following line to your ~/.emacs file to make these formatting rules the default: (add-hook 'c-mode-common-hook (function (lambda () (c-set-style "BSD")))) * Function declarations must look like this: /**/ int foo(char *s, char **p) { function body } There must be an empty line, a line with "/**/", a line with the type of the function, and finally the name of the function with typed arguments. These lines must not be indented. The script generating function prototypes and the ansi2knr program depend on this format. * Variable declarations must similarly be preceded by a line containing only "/**/", for the prototype generation script. The declaration itself should be all on one line (except for multi-line initialisers). * Preprocessor directives that affect the function/variable declarations must also be preceded by a "/**/" line, so that they get copied into the prototype lists. * There are three levels of visibility for a function or variable. It can be file-local, for which it must be marked with the keyword "static" at the front of the declaration. It can be visible to other object files in the same module, for which it requires no extra keyword. Or it can be made available to the entire program (including other dynamically loaded modules), for which it must be marked with the pseudo-keyword "mod_export" at the front of the declaration. Symbols should have the least visibility possible. * Leave a blank line between the declarations and statements in a compound statement, if both are present. Use blank lines elsewhere to separate groups of statements in the interests of clarity. There should never be two consecutive blank lines. * Each .c file *must* #include the .mdh header for the module it is a part of and then its own .pro file (for local prototypes). It may also #include other system headers. It *must not* #include any other module's headers or any other .pro files. * The repository includes a `.editorconfig' file with whitespace/indent control settings. Information about text editor plugins and this file can be found at . Modules ------- Modules have hierarchical names. Name segments are separated by `/', and each segment consists of alphanumerics plus `_'. Relative names are never used; the naming hierarchy is strictly for organisational convenience. Each module is described by a file with a name ending in `.mdd' somewhere under the Src directory. This file is actually a shell script that will sourced when zsh is built. To describe the module it can/should set the following shell variables: - name name of the module - link `static', `dynamic' or `no', as described in INSTALL. In addition, the value `either' is allowed in the .mdd file, which will be converted by configure to `dynamic' if that is available, else `static'. May also be a command string, which will be run within configure and whose output is used to set the value of `link' in config.modules. This allows a system-specific choice of modules. For example, link='case $host in *-hpux*) echo dynamic; ;; *) echo no; ;; esac' - load `yes' or `no': whether the shell should include hooks for loading the module automatically as necessary. (This corresponds to an `L' in xmods.conf in the old mechanism.) - moddeps modules on which this module depends (default none) - nozshdep non-empty indicates no dependence on the `zsh/main' pseudo-module - alwayslink if non-empty, always link the module into the executable - autofeatures features defined by the module for autoloading, a space-separated list. The syntax for features is as for zmodload -F, e.g. b:mybin refers to the builtin mybin. This replaces the previous mechanism with separate variables for builtins, conditions, math functions and parameters. Note the features are only available in zsh's native mode, not in emulation modes. - autofeatures_emu As autofeatures, but the features so presented are available in modes that are *not* zsh's native mode. The variable autofeatures must also be present. - objects .o files making up this module (*must* be defined) - proto .syms files for this module (default generated from $objects) - headers extra headers for this module (default none) - hdrdeps extra headers on which the .mdh depends (default none) - otherincs extra headers that are included indirectly (default none) Be sure to put the values in quotes. For further enlightenment have a look at the `mkmakemod.sh' script in the Src directory of the distribution. Modules have to define six functions which will be called automatically by the zsh core. The first one, named `setup_', should set up any data needed in the module, at least any data other modules may be interested in. The next pair are `features_' and `enables_' and deal with enabling module features. Ensure you are familiar with the description of features under `zmodload -F'. The function features_ takes an argument `char ***featuresp'; *featuresp is to be set to a NULL-terminated array containing a list of all the features. It should then return zero. It may return one to indicate features are not supported, but this is not recommended. The function featuresarray conveniently interrogates the module's feature structures for all standard features; space is left for abstract features at the end of the array and the names must be added by the module. Note that heap memory should be used for this (zhalloc, etc.) as memory for the features array is not freed; note also the pointers for the abstract features are not initialised so setting them is mandatory any time there are any present. A structure "struct features" should be used to contain all standard features as well as the number of abstract features (those only understood by the module itself). See below. enables_ takes an argument `int **enablesp'. If *enablesp is NULL, it should be set to an array of the same length as *featuresp without the NULL, containing a 1 for every feature that is enabled and a zero for other feature. By default features are disabled. If *enablesp is not NULL, its values should be used to decide whether features are to be turned off. It should return status 0 for success, 1 on a failure to alter a feature. The function handlefeatures() conveniently handles all standard features present in the module's features structure; abstract features must be handled by the module (as with the features array, the area of the enables array for abstract features is not even initialised by the main shell). As with `features_', any handling of the array by the module itself should take into account that the array will not be freed and any allocation should therefore be from heap memory. The functions `features_' and `enables_' can be called at any point after `setup_' has been called and before `cleanup_' is called. In particular they can be called before or after `boot_'. The function named `boot_' should register function wrappers, hooks and anything that will be visible to the user that is not handled by features_ and enables_ (so features should not be turned on here). It will be called after the `setup_'-function, and also after the initial set of features have been set by calls to `features_' and `enables_'. The function named `cleanup_', is called when the user tries to unload a module and should de-register all features and hooks. A call to setfeatures with the final argument NULL will remove all standard features present in the module's features structure. Note that `cleanup_' is called whenever `setup_' succeeded, so that `cleanup_' must be prepared to handle any state resulting from a failed `boot_' or initial call to `features_'. Note also that a return code of 1 from `cleanup_' will result in the module not being unloaded, so usually `cleanup_' will return 0 even if it has to handle an unclean state; if it does return 1, it must be prepared to be called again in a future attempt to unload. The last function, `finish_' is called when the module is actually unloaded and should finalize all the data initialized in the `setup_'-function. However, `finish_' is called even if `setup_' failed, so it should not rely on the module successfully being set up. The state from `finish_' module is currently ignored; it is called too late to prevent the module from being unloaded. *Note* in addition to freeing memory, variables associated with allocated memory should be set to NULL or to indicate arrays are empty, etc. It should not be assumed that the variables will automatically be zeroed if the module is reloaded (though some configurations may do this). In short, the `cleanup_'-function should undo what the `boot_'-function did (together with handling any residual effects of `enables_'), but should not rely on `boot_' having been successful, and the `finish_'-function should undo what the `setup_'-function did, but should not rely on `setup_' having been successful. All of these functions should return zero if they succeeded and non-zero otherwise. Features ======== Builtins, conditions, parameters (variables) and math functions are described as "features". They should be made available to the shell by declaring a `struct feature' for each module. Below are descriptions of the individual features; first here is generic information. `struct feature' contains a pointer to the array that declares each feature, followed by the number of entries in the array. The pointer can be NULL and the size zero for any feature that is not present in the module. For example, to register only builtins in zsh and thereby make them visible to the user, the structure should contain "bintab" where the array is declared as an array of struct builtin, as discussed below: static struct feature module_features = { bintab, sizeof(bintab)/sizeof(*bintab), NULL, 0, /* declare any conditions here */ NULL, 0, /* declare any parameters here */ NULL, 0, /* declare any math functions here */ 0, /* number of abstract features */ } Within each individual table ("bintab", etc.), features should be listed in ASCII order as no further sorting is performed by the shell when features are listed. Abstract features are handled by the module; the number present in `struct features' is there to ensure the main shell allocated space in the features and enables array in the standard featuresarray() and handlefeatures() calls. However, the inserting of names in the features array and the getting and setting of feature enables is left entirely to the module. Note that abstract features should not contain a colon (to avoid clashes with the prefixes used in standard features). It is recommended that only alphanumerics, - and _ be used in the names of abstract features, and - not be the first character (to avoid confusion with disabling features) but this is not required by the main shell. The features_ and enables_ functions for such a module will look like: /**/ int features_example(Module m, char ***features) { *features = featuresarray(m->nam, &module_features); /* fill in any abstract features in (*features) here */ return 0; } /**/ int enables_example(Module m, int **enables) { int ret; ret = handlefeatures(m->nam, &module_features, enables); /* handle any abstract features here */ ... return ret; } The functions shown take the name of the module, the set of features, To de-register builtins, pass the features structure to setfeatureenables with a NULL final value: /**/ int cleanup_example(Module m) { setfeatureenables(m->nam, &module_features, NULL); ... } Builtins -------- Builtins are described in a table, for example: static struct builtin bintab[] = { BUILTIN("example", 0, bin_example, 0, -1, 0, "flags", NULL), }; Here `BUILTIN(...)' is a macro that simplifies the description. Its arguments are: - the name of the builtin as a string - optional flags (see BINF_* in zsh.h) - the C-function implementing the builtin - the minimum number of arguments the builtin needs - the maximum number of arguments the builtin can handle or -1 if the builtin can get any number of arguments - an integer that is passed to the handler function and can be used to distinguish builtins if the same C-function is used to implement multiple builtins - the options the builtin accepts, given as a string containing the option characters (the above example makes the builtin accept the options `f', `l', `a', `g', and `s'). Passing NULL here disables all flag handling, i.e. even "--". - and finally a optional string containing option characters that will always be reported as set when calling the C-function (this, too, can be used when using one C-function to implement multiple builtins) The definition of the handler function looks like: /**/ static int bin_example(char *nam, char **args, char *ops, int func) { ... } The special comment /**/ is used by the zsh Makefile to generate the `*.pro' files. The arguments of the function are the number under which this function was invoked (the name of the builtin, but for functions that implement more than one builtin this information is needed). The second argument is the array of arguments *excluding* the options that were defined in the struct and which are handled by the calling code. These options are given as the third argument. It is an array of 256 characters in which the n'th element is non-zero if the option with ASCII-value n was set (i.e. you can easily test if an option was used by `if (ops['f'])' etc.). The last argument is the integer value from the table (the sixth argument to `BUILTIN(...)'). The integer return value by the function is the value returned by the builtin in shell level. Conditions ---------- The definition of condition codes in modules is equally simple. First we need a table with the descriptions: static struct conddef cotab[] = { CONDDEF("len", 0, cond_p_len, 1, 2, 0), CONDDEF("ex", CONDF_INFIX, cond_i_ex, 0, 0, 0), }; Again a macro is used, with the following arguments: - the name of the condition code without the leading hyphen (i.e. the example makes the condition codes `-len' and `-ex' usable in `[[...]]' constructs) - an optional flag which for now can only be CONDF_INFIX; if this is given, an infix operator is created (i.e. the above makes `[[ -len str ]]' and `[[ s1 -ex s2 ]]' available) - the C-function implementing the conditional - for non-infix condition codes the next two arguments give the minimum and maximum number of string the conditional can handle (i.e. `-len' can get one or two strings); as with builtins giving -1 as the maximum number means that the conditional accepts any number of strings - finally as the last argument an integer that is passed to the handler function that can be used to distinguish different condition codes if the same C-function implements more than one of them The definition for the function looks like: /**/ static int cond_p_len(char **a, int id) { ... } The first argument is an array containing the strings (NULL-terminated like the array of arguments for builtins), the second argument is the integer value stored in the table (the last argument to `CONDDEF(...)'). The value returned by the function should be non-zero if the condition is true and zero otherwise. Note that no preprocessing is done on the strings. This means that no substitutions are performed on them and that they will be tokenized. There are three helper functions available: - char *cond_str(args, num, raw) The first argument is the array of strings the handler function got as an argument and the second one is an index into this array. The return value is the num'th string from the array with substitutions performed. If the last argument is zero, the string will also be untokenized. - long cond_val(args, num) The arguments are the same as for cond_str(). The return value is the result of the mathematical evaluation of the num'th string form the array. - int cond_match(args, num, str) Again, the first two arguments are the same as for the other functions. The third argument is any string. The result of the function is non-zero if the num'th string from the array taken as a glob pattern matches the given string. Parameters ---------- For defining parameters, a module can call `createparam()' directly or use a table to describe them, e.g.: static struct paramdef patab[] = { PARAMDEF("foo", PM_INTEGER, NULL, get_foo, set_foo, unset_foo), INTPARAMDEF("exint", &intparam), STRPARAMDEF("exstr", &strparam), ARRPARAMDEF("exarr", &arrparam), }; There are four macros used: - PARAMDEF() gets as arguments: - the name of the parameter - the parameter flags to set for it (from the PM_* flags defined in zsh.h) - optionally a pointer to a variable holding the value of the parameter - three functions that will be used to get the value of the parameter, store a value in the parameter, and unset the parameter - the other macros provide simple ways to define the most common types of parameters; they get the name of the parameter and a pointer to a variable holding the value as arguments; they are used to define integer-, scalar-, and array-parameters, so the variables whose addresses are given should be of type `long', `char *', and `char **', respectively For a description of how to write functions for getting or setting the value of parameters, or how to write a function to unset a parameter, see the description of the following functions in the `params.c' file: - `intvargetfn()' and `intvarsetfn()' for integer parameters - `strvargetfn()' and `strvarsetfn()' for scalar parameters - `arrvargetfn()' and `arrvarsetfn()' for array parameters - `stdunsetfn()' for unsetting parameters Note that if one defines parameters using the last two macros (for scalars and arrays), the variable holding the value should be initialized to either `NULL' or to a piece of memory created with `zalloc()'. But this memory should *not* be freed in the finish-function of the module because that will be taken care of by the `deleteparamdefs()' function described below. It is also possible to declare special parameters using the macro SPECIALPMDEF(). More care is required in this case. See, for example, many of the definitions in Src/Modules/parameter.c. Math functions -------------- Modules can also define math functions. Again, they are described using a table: static struct mathfunc mftab[] = { NUMMATHFUNC("sum", math_sum, 1, -1, 0), STRMATHFUNC("length", math_length, 0), }; The `NUMMATHFUNC()' macro defines a math function that gets an array of mnumbers (the zsh type for representing values in arithmetic expressions) taken from the string in parentheses at the function call. Its arguments are the name of the function, the C-function implementing it, the minimum and maximum number of arguments (as usual, the later may be `-1' to specify that the function accepts any number of arguments), and finally an integer that is given unchanged to the C-function (to be able to implement multiple math functions in one C-function). The `STRMATHFUNC()' macro defines a math function that gets the string in parentheses at the call as one string argument (without the parentheses). The arguments are the name of the function, the C-function, and an integer used like the last argument of `NUMMATHFUNC()'. The C-functions implementing the math functions look like this: /**/ static mnumber math_sum(char *name, int argc, mnumber *argv, int id) { ... } /**/ static mnumber math_length(char *name, char *arg, int id) { ... } Functions defined with `NUMMATHFUNC' get the name of the function, the number of numeric arguments, an array with these arguments, and the last argument from the macro-call. Functions defined with `STRMATHFUNC' get the name of the function, the string between the parentheses at the call, and the last argument from the macro-call. Both types of functions return an mnumber which is a discriminated union looking like: typedef struct { union { zlong l; double d; } u; int type; } mnumber; The `type' field should be set to `MN_INTEGER' or `MN_FLOAT' and depending on its value either `u.l' or `u.d' contains the value. Hooks ----- Modules can also define function hooks. Other modules can then add functions to these hooks to make the first module call these functions instead of the default. These are not handled by the features mechanism as they are not directly visible to the user. Again, an array is used to define hooks: static struct hookdef foohooks[] = { HOOKDEF("foo", foofunc, 0), }; The first argument of the macro is the name of the hook. This name is used whenever the hook is used. The second argument is the default function for the hook or NULL if no default function exists. The last argument is used to define flags for the hook. Currently only one such flag is defined: `HOOKF_ALL'. If this flag is given and more than one function was added to the hook, all functions will be called (including the default function). Otherwise only the last function added will be called. The functions that can be used as default functions or that can be added to a hook have to be defined like: /**/ static int foofunc(Hookdef h, void *data) { ... } The first argument is a pointer to the struct defining the hook. The second argument is an arbitrary pointer that is given to the function used to invoke hooks (see below). The functions to register and de-register hooks look like those for the other things that can be defined by modules: /**/ int boot_foo(Module m) { int ret; ret = addhookdefs(m->nam, foohooks, sizeof(foohooks)/sizeof(*foohooks)) ... } ... /**/ int cleanup_foo(Module m) { deletehookdefs(m->nam, foohooks, sizeof(foohooks)/sizeof(*foohooks)); ... } Modules that define hooks can invoke the function(s) registered for them by calling the function `runhook(name, data)'. The first argument is the name of the hook and the second one is the pointer given to the hook functions as their second argument. Hooks that have the `HOOKF_ALL' flag call all function defined for them until one returns non-zero. The return value of `runhook()' is the return value of the last hook function called or zero if none was called. To add a function to a hook, the function `addhookfunc(name, func)' is called with the name of the hook and a hook function as arguments. Deleting them is done by calling `deletehookfunc(name, func)' with the same arguments as for the corresponding call to `addhookfunc()'. Alternative forms of the last three function are provided for hooks that are changed or called very often. These functions, `runhookdef(def, data)', `addhookdeffunc(def, func)', and `deletehookdeffunc(def, func)' get a pointer to the `hookdef' structure defining the hook instead of the name and otherwise behave like their counterparts. Wrappers -------- Finally, modules can define wrapper functions. These functions are called whenever a shell function is to be executed. Again, they are not handled by the features mechanism as they are not visible to the user. The definition is simple: static struct funcwrap wrapper[] = { WRAPDEF(ex_wrapper), }; The macro `WRAPDEF(...)' gets the C-function as its only argument. This function should be defined like: /**/ static int ex_wrapper(List list, FuncWrap w, char *name) { ... runshfunc(list, w, name); ... return 0; } The first two arguments should only be used to pass them to `runshfunc()' which will execute the shell function. The last argument is the name of the function to be executed. The arguments passed to the function can be accessed vie the global variable `pparams' (a NULL-terminated array of strings). The return value of the wrapper function should be zero if it calls `runshfunc()' itself and non-zero otherwise. This can be used for wrapper functions that only need to run under certain conditions or that don't need to clean anything up after the shell function has finished: /**/ static int ex_wrapper(List list, FuncWrap w, char *name) { if (wrapper_need_to_run) { ... runshfunc(list, w, name); ... return 0; } return 1; } Inside these wrapper functions the global variable `sfcontext' will be set to a clue indicating the circumstances under which the shell function was called. It can have any of the following values: - SFC_DIRECT: the function was invoked directly by the user - SFC_SIGNAL: the function was invoked as a signal handler - SFC_HOOK: the function was automatically invoked as one of the special functions known by the shell (like `chpwd') - SFC_WIDGET: the function was called from the zsh line editor as a user-defined widget - SFC_COMPLETE: the function was called from the completion code (e.g. with `compctl -K func') If a module invokes a shell function (e.g. as a hook function), the value of this variable should only be changed temporarily and restored to its previous value after the shell function has finished. There is a problem when the user tries to unload a module that has defined wrappers from a shell function. In this case the module can't be unloaded immediately since the wrapper function is still on the call stack. The zsh code delays unloading modules until all wrappers from them have finished. To hide this from the user, the module's cleanup function is run immediately so that all builtins, condition codes, and wrapper function defined by the module are de-registered. But if there is some module-global state that has to be finalized (e.g. some memory that has to be freed) and that is used by the wrapper functions finalizing this data in the cleanup function won't work. This is why there are two functions each for the initialization and finalization of modules. The `boot'- and `cleanup'-functions are run whenever the user calls `zmodload' or `zmodload -u' and should only register or de-register the module's interface that is visible to the user. Anything else should be done in the `setup'- and `finish'-functions. Otherwise modules that other modules depend upon may destroy their state too early and wrapper functions in the latter modules may stop working since the state they use is already destroyed. Documentation ------------- * Edit only the .yo files. All other formats (man pages, TeXinfo, HTML, etc.) are automatically generated from the yodl source. * Always use the correct markup. em() is used for emphasis, and bf() for citations. tt() marks text that is literal input to or output from the shell. var() marks metasyntactic variables. * In addition to appropriate markup, always use quotes (`') where appropriate. Specifically, use quotes to mark text that is not a part of the actual text of the documentation (i.e., that it is being quoted). In principle, all combinations of quotes and markup are possible, because the purposes of the two devices are completely orthogonal. For example, Type `tt(xyzzy)' to let zsh know you have played tt(advent). Saying `plugh' aloud doesn't have much effect, however. In this case, "zsh" is normal text (a name), "advent" is a command name occurring in the main text, "plugh" is a normal word that is being quoted (it's the user that says `plugh', not the documentation), and "xyzzy" is some text to be typed literally that is being quoted. * For multiple-line pieces of text that should not be filled, there are various models. - If the text is pure example, i.e. with no metasyntactic variables etc., it should be included within `example(...)'. The text will be indented, will not be filled and will be put into a fixed width font. - If the text includes mixed fonts, it should be included within `indent(...)'. The text is now filled unless `nofill(...)' is also used, and explicit font-changing commands are required inside. - If the text appears inside some other format, such as for example the `item()' list structure, then the instruction `nofill(...)', which simply turns off filling should be used; as with `indent(...)', explicit font changing commands are required. This can be used without `indent()' when no indentation is required, e.g. if the accumulated indentation would otherwise be too long. All the above should appear on their own, separated by newlines from the surrounding text. No extra newlines after the opening or before the closing parenthesis are required. Module names ------------ Modules have hierarchical names. Name segments are separated by `/', and each segment consists of alphanumerics plus `_'. Relative names are never used; the naming hierarchy is strictly for organisational convenience. Top-level name segments should be organisational identifiers, assigned by the Zsh Development Group and recorded here: top-level identifier organisation -------------------- ------------ x_* reserved for private experimental use zsh The Zsh Development Group (contact: ) Below the top level, naming authority is delegated. Distribution of files --------------------- zsh is distributed in two parts: a "src" distribution containing all the source files (roughly, but not exactly, corresponding to the git tree), and a "doc" distribution containing some pre-built files from the documentation directory. All the files in the "doc" distribution may be generated from files in the "src" distribution with appropriate freely available tools. To indicate which files should be distributed, each directory in the git tree includes a file .distfiles that sets any number of a set of Bourne shell (scalar) parameters. The value of the parameter is expanded as a set of standard command line arguments. Apart from DISTFILES_NOT, which must be an explicit list of files separated by whitespace, basic globbing is allowed in the values. Because of the way DISTFILES_SRC is constructed it is only possible to make a release from a git checkout. The following parameters are currently used: - DISTFILES_SRC is a list of files from the directory for the "src" distribution. However, if the file .distfiles is present in a directory, all files known to git will be added to DISTFILES_SRC except for files listed explicitly in DISTFILES_NOT. - DISTFILES_DOC is a list of files from the directory for the "doc" distribution. - DISTFILES_NOT is a list of files that will not be included in a distribution even though they are present in the git tree.