Author:         Jan Nijtmans <[email protected]>
State:          Final
Type:           Project
Vote:           Done
Created:        4-Nov-2020
Post-History:
Keywords:       package
Tcl-Version:    8.7
Tcl-Branch:	tip-590
Vote-Summary:	Accepted 3/0/2
Votes-For:	JN, KW, MC
Votes-Against:	none
Votes-Present:	FV, SL

Abstract

This TIP proposes to rename some package names to lowercase, and recommend lowercase packagenames.

Rationale

Let's run the "package names" command. Possible outcome:

    % package names
    Thread http tcl::tommath TclOO tcl::idna opt tcltest zipfs cookiejar msgcat zlib Ttrace Tcl platform sqlite3 Tk

From this, we cannot really see where those packages came from. Some are distributed from within Tcl (tcl::tommath, zlib, TclOO, zipfs), some are distributed as tm modules (http, msgcat, platform), some are in the battery-included Tcl distribution (Thread, Ttrace, sqlite3).

Further on, on Windows there are 2 packages which' entry points symbols cannot be guessed. The reason is their filenames: "tcldde14.dll" resp. "tclreg13.dll", while their package names are "dde" resp. "registry"

Specification

In order to bring some consistency in package names, this TIP proposes to rename some packages. The old package names are kept as well.
- TclOO ⟶ tcl::oo
- zipfs ⟶ tcl::zipfs
- zlib ⟶ tcl::zlib
- Tcl ⟶ tcl
- Tcltest ⟶ tcl::test
- Tk ⟶ tk
- Tktest ⟶ tk::test

This means that both "package require tcl" and "package require Tcl" can be used interchangably. But "package require TCL" won't work. The old names will be deprecated, but not removed, not even in Tcl 9.0.

From now on, the recommended way to name packages is lowercase.
Extend the "load" command, such that if a library name starts with "tcl" (or contains "tcl" just after the starting "lib"), this part will be stripped completely in stead of only the "lib" part. This makes the entry symbol of "tcldde13.dll" guessable.
Rename the directory "reg" to "registry" and the file "tclreg14.dll" to "tclregistry14.dll". This makes the entry point "Registry_Init" guessable from the filename.

Caveat

The "load" and "unload" command have an optional ?packageName? argument, which isn't actually a packageName at all. It's more like a prefix, which is title-cased and appended with "_Init" (or "_Unload") for determining the initialization function of the loaded library. There's a separate ticket on that. That's why the "load" and "unload" still use Titlecase arguments like "Tk", not "tk". Originally, solving this was part of this TIP, but it's out of scope now: It's not necessary to make the transition to lowercase package names, so this can be solved separately later.

The same holds for the packageName argument of the Tcl_StaticPackage() function, this argument should still be Titlecase as well.

Compatibility

This is almost 100% compatible with Tcl 8.5/8.6. UPPERCASE or Titlecase package names still work as before. The only possible difference is made in package names starting with "tcl", such as "Tclx". Such packages cannot be "load"ed any more without explicitly naming the "Tclx" prefix. I tested TclX with this change, and it works fine, because it's pkgIndex contains an implicit "Tclx" prefix.

Reference Implementation

In tcl branch "tip-590". Tk has its "tip-590" branch too.

Copyright

This document has been placed in the public domain.