NAME
pkgmkIndex - Build an index for automatic loading of packages
SYNOPSIS
ppkkggmmkkIInnddeexx ??-direct? ?-lazy? ?-load pkgPat? ?-verbose? dir ?pattern pattern ...?|
DESCRIPTION
PPkkggmmkkIInnddeexx is a utility procedure that is part of the standard Tcl library. It is used to create index files that allow packages to be loaded automatically when ppaacckkaaggee rreeqquuiirree commands are executed. To use ppkkggmmkkIInnddeexx, follow these steps: [1] Create the package(s). Each package may consist of one or more Tcl script files or binary files. Binary files must be suitable for loading with the llooaadd command with a single argument; for example, if the file is tteesstt..ssoo it must be possible to load thisfile with the command llooaadd tteesstt..ssoo. Each script file must con-
tain a ppaacckkaaggee pprroovviiddee command to declare the package and ver-
sion number, and each binary file must contain a call to TTccllPPkkggPPrroovviiddee. [2] Create the index by invoking ppkkggmmkkIInnddeexx. The dir argument gives the name of a directory and each pattern argument is agglloobb-style pattern that selects script or binary files in dir. |
The default pattern is **..ttccll and **..[[iinnffoo sshhaarreeddlliibbeexxtteennssiioonn]]. PPkkggmmkkIInnddeexx will create a file ppkkggIInnddeexx..ttccll in dir with package information about all the files given by the pattern arguments. It does this by loading each file into a slave interpreter and seeing what packages and new commands appear (this is why it is essential to have ppaacckkaaggee pprroovviiddee commands or TTccllPPkkggPPrroovviiddee calls in the files, as described above). If you have a packagesplit among scripts and binary files, or if you have dependen-
cies among files, you may have to use the -llooaadd option or adjust
the order in which ppkkggmmkkIInnddeexx processes the files. See COMPLEX CASES below. [3] Install the package as a subdirectory of one of the directoriesgiven by the ttccllppkkggPPaatthh variable. If $$ttccllppkkggPPaatthh contains
more than one directory, machine-dependent packages (e.g., those
that contain binary shared libraries) should normally beinstalled under the first directory and machine-independent
packages (e.g., those that contain only Tcl scripts) should be installed under the second directory. The subdirectory should include the package's script and/or binary files as well as the ppkkggIInnddeexx..ttccll file. As long as the package is installed as asubdirectory of a directory in $$ttccllppkkggPPaatthh it will automati-
cally be found during ppaacckkaaggee rreeqquuiirree commands. If you install the package anywhere else, then you must ensure that the directory containing the package is in the aauuttooppaatthh global variable or an immediate subdirectory of one of thedirectories in aauuttooppaatthh. AAuuttooppaatthh contains a list of directo-
ries that are searched by both the auto-loader and the package
loader; by default it includes $$ttccllppkkggPPaatthh. The package loader
also checks all of the subdirectories of the directories in aauuttooppaatthh. You can add a directory to aauuttooppaatthh explicitly inyour application, or you can add the directory to your TTCCLLLLIIBB-
PPAATTHH environment variable: if this environment variable is present, Tcl initializes aauuttooppaatthh from it during application startup. [4] Once the above steps have been taken, all you need to do to usea package is to invoke ppaacckkaaggee rreeqquuiirree. For example, if ver-
sions 2.1, 2.3, and 3.1 of package TTeesstt have been indexed by ppkkggmmkkIInnddeexx, the command ppaacckkaaggee rreeqquuiirree TTeesstt will make version3.1 available and the command ppaacckkaaggee rreeqquuiirree -eexxaacctt TTeesstt 22..11
will make version 2.1 available. There may be many versions of a package in the various index files in aauuttooppaatthh, but only one will actually be loaded in a given interpreter, based on the first call to ppaacckkaaggee rreeqquuiirree. Different versions of a package may be loaded in different interpreters. OOPPTTIIOONNSS The optional switches are:-ddiirreecctt The generated index will implement direct loading of the
package upon ppaacckkaaggee rreeqquuiirree. This is the default.-llaazzyy The generated index will manage to delay loading the
package until the use of one of the commands provided by the package, instead of loading it immediately upon ppaacckkaaggee rreeqquuiirree.-llooaadd pkgPat The index process will pre-load any packages that exist
in the current interpreter and match pkgPat into theslave interpreter used to generate the index. The pat-
tern match uses string match rules, but without making case distinctions. See COMPLEX CASES below.-vveerrbboossee Generate output during the indexing process. Output is
via the ttccllLLoogg procedure, which by default prints to stderr.-- End of the flags, in case dir begins with a dash.
PPAACCKKAAGGEESS AANNDD TTHHEE AAUUTTOO-LLOOAADDEERR
The package management facilities overlap somewhat with the auto-
loader, in that both arrange for files to be loaded on-demand. How-
ever, package management is a higher-level mechanism that uses the
auto-loader for the last step in the loading process. It is generally
better to index a package with ppkkggmmkkIInnddeexx rather than aauuttoommkkiinnddeexxbecause the package mechanism provides version control: several ver-
sions of a package can be made available in the index files, with dif-
ferent applications using different versions based on ppaacckkaaggee rreeqquuiirree commands. In contrast, aauuttoommkkiinnddeexx does not understand versions so it can only handle a single version of each package. It is probably not a good idea to index a given package with both ppkkggmmkkIInnddeexx and aauuttoommkkiinnddeexx. If you use ppkkggmmkkIInnddeexx to index a package, its commandscannot be invoked until ppaacckkaaggee rreeqquuiirree has been used to select a ver-
sion; in contrast, packages indexed with aauuttoommkkiinnddeexx can be used immediately since there is no version control. HHOOWW IITT WWOORRKKSS PPkkggmmkkIInnddeexx depends on the ppaacckkaaggee uunnkknnoowwnn command, the ppaacckkaaggeeiiffnneeeeddeedd command, and the auto-loader. The first time a ppaacckkaaggee
rreeqquuiirree command is invoked, the ppaacckkaaggee uunnkknnoowwnn script is invoked. This is set by Tcl initialization to a script that evaluates all of the ppkkggIInnddeexx..ttccll files in the aauuttooppaatthh. The ppkkggIInnddeexx..ttccll files contain ppaacckkaaggee iiffnneeeeddeedd commands for each version of each available package;these commands invoke ppaacckkaaggee pprroovviiddee commands to announce the avail-
ability of the package, and they setup auto-loader information to load
the files of the package. If the -lazy flag was provided when the |
ppkkggIInnddeexx..ttccll was generated, a given file of a given version of a given package isn't actually loaded until the first time one of its commands is invoked. Thus, after invoking ppaacckkaaggee rreeqquuiirree you may not see the package's commands in the interpreter, but you will be able to invokethe commands and they will be auto-loaded.
DDIIRREECCTT LLOOAADDIINNGG | Some packages, for instance packages which use namespaces and export | commands or those which require special initialization, might select | that their package files be loaded immediately upon ppaacckkaaggee rreeqquuiirree | instead of delaying the actual loading to the first use of one of the | package's command. This is the default mode when generating the package |index. It can be overridden by specifying the -lazy argument.
CCOOMMPPLLEEXX CCAASSEESS Most complex cases of dependencies among scripts and binary files, and packages being split among scripts and binary files are handled OK. However, you may have to adjust the order in which files are processed by ppkkggmmkkIInnddeexx. These issues are described in detail below.If each script or file contains one package, and packages are only con-
tained in one file, then things are easy. You simply specify all files to be indexed in any order with some glob patterns.In general, it is OK for scripts to have dependencies on other pack-
ages. If scripts contain ppaacckkaaggee rreeqquuiirree commands, these are stubbed out in the interpreter used to process the scripts, so these do not cause problems. If scripts call into other packages in global code, these calls are handled by a stub uunnkknnoowwnn command. However, if scripts make variable references to other package's variables in global code, these will cause errors. That is also bad coding style. If binary files have dependencies on other packages, things can becometricky because it is not possible to stub out C-level APIs such as
TTccllPPkkggRReeqquuiirree API when loading a binary file. For example, suppose the BLT package requires Tk, and expresses this with a call to TTccllPPkkggRReeqquuiirree in its BBllttIInniitt routine. To support this, you must run ppkkggmmkkIInnddeexx in an interpreter that has Tk loaded. You can achieve thiswith the -llooaadd pkgPat option. If you specify this option, ppkkggmmkkIInnddeexx
will load any packages listed by iinnffoo llooaaddeedd and that match pkgPat into the interpreter used to process files. In most cases this will satisfy the TTccllPPkkggRReeqquuiirree calls made by binary files. If you are indexing two binary files and one depends on the other, you should specify the one that has dependencies last. This way the one without dependencies will get loaded and indexed, and then the package it provides will be available when the second file is processed. You may also need to load the first package into the temporary interpreterused to create the index by using the -llooaadd flag; it won't hurt to
specify package patterns that are not yet loaded. If you have a package that is split across scripts and a binary file,then you should avoid the -llooaadd flag. The problem is that if you load a
package before computing the index it masks any other files that pro-
vide part of the same package. If you must use -llooaadd, then you must
specify the scripts first; otherwise the package loaded from the binary file may mask the package defined by the scripts.SEE ALSO
package(n) KKEEYYWWOORRDDSSauto-load, index, package, version
Tcl 8.3 pkgmkIndex(n)