Distribution mechanisms for Tcl source and binaries
One of several delivery systems
(one can also use ftp or http or mount and other cd-rom, etc. access tools to access source or binary code and use cp, ginstall, etc. to manage the packages. And of course some OSes (for instance, Debian, MacOSX) etc. have package management tools as well).
KJN I have started this page because I am beginning to get confused by the number of possible distribution mechanisms.
Neil Madden pointed out [L1 ] that package require delegates actual loading of packages to either source (for Tcl scripts) or load (for binary extensions).
Local repository access by package
LV I'm confused by what you mean by distribution mechanism. Do you mean formats in which code can be distributed to users or do you mean mechanisms by which users can locate new extensions or do you mean means by which a program can invoke other code or what?
The reason I ask is because Teacup seems different than the other items on the above list - and there are certainly other repositories other than teacup.
Also, I don't see listed in the above list things like "zip files", "starkits", "tar files", "opening a file and reading in code", "exec", "opening a pipe", etc.
Perhaps after we know better what you are after, more information can be added.
KJN Sorry for the lack of clarity - I followed Tcl Modules which had been placed in Category Distribution.
I'm interested in the ways that binary or Tcl code can be organised into an extension, so that when a script running on a stock Tcl installation requires an extension's functionality, the script can access the extension either automatically or by issuing a simple command. So I suppose I'm looking for means by which a program can locate and invoke extensions that will run in the same interpreter in the same process. The user who needs to locate a missing extension, and the program that invokes another process (exec) or accesses another process by IPC, are different problems.
The simplest way to do this when organising one's own Tcl code is to use source; but when a piece of code has well-defined functionality, and is intended for re-use in different projects, it is convenient to organise it as a package: this is how most libraries are provided at present.
Tcl Modules and Teacup are innovations, and I would be glad of any comments on how these fit in with the older commands. Teacup appears to differ from package require by fetching modules from a repository, rather than looking in the system's Tcl installation.
LV Actually, teacup sets up a teapot environment whereby one can manage a couple of variants of local repositories, or access a variety of remote repositories. HOWEVER, the teapot repository framework is a delivery mechanism. The other items on your list are language file formats and processes. There is really a fundamental difference, in my mind, between the two. Teacup is a program which manages how stuff gets into a directory. Why not list cp, unzip, gtar, etc. as they are parallels to teacup?
The other things on your list are the various file formats that people have used to create packages (a.k.a modules or extensions) that, when loaded, provide new tcl commands.
auto_load appears to be an older mechanism, but it is still used by the Tcl and Tk cores and a few libraries. Should it be deprecated?
Please discuss.
LV Good question. I would think that some of the criteria for deprecating a command would be:
KJN It would be feasible to modify tclPkgUnknown so that a running script would automatically use teacup to try to fetch missing packages from the archive repository.
Clearly a network connection would be needed, and user feedback might be requested; but if the alternative is that the script fails because of a missing package, perhaps these hardships can be tolerated.
See also: