[TCLCORE] New tip #722

[Christian W. <Chr...@t-...>]

Hello all,

(posted again in case I've sent it with the wrong account)

please could some tip fossil maintainer add the following tip.

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# TIP 722 Improve **package present** subcommand
         Author:         Christian Werner <und...@gm...>
         State:          Draft
         Type:           Project
         Created:        19-May-2025
         Keywords:       Tcl,package
-----

# Abstract

This TIP proposes to improve the **package present** subcommand such
that it can be used to return a list of all currently loaded packages.

# Rationale

Although there is a **package names** subcommand which returns a list of
all currently available packages there's no equivalent to retrieve the
list of currently loaded packages. However, the latter can be of use
e.g. to build a software bill of materials of an application or to help
in generating a package dependency graph.

# Specification

For **package present** without any further arguments (which currently
generates an error message) the implementation of **package names** is
borrowed but its selection clause while iterating over the package hash
table is changed to add package names to the result list for which a
version is known (which means that the package has been loaded).

** Implementation

The code block to add to the current **package present** implementation is:

'''
if (objc < 3) {
     Tcl_Obj *resultObj;

     TclNewObj(resultObj);
     tablePtr = &iPtr->packageTable;
     for (hPtr = Tcl_FirstHashEntry(tablePtr, &search); hPtr != NULL;
              hPtr = Tcl_NextHashEntry(&search)) {
         pkgPtr = Tcl_GetHashValue(hPtr);
         if (pkgPtr->version != NULL) {
             Tcl_ListObjAppendElement(NULL, resultObj, Tcl_NewStringObj(
                     Tcl_GetHashKey(tablePtr, hPtr), -1));
         }
     }
     Tcl_SetObjResult(interp, resultObj);
     break;
}
'''

The test code in ```package.test``` must be changed for test case 8.11 to:

```
test package-8.11 {Tcl_PackageCmd procedure, "present" option} -body {
     package present
} -match glob -result *
```

# Copyright

This document has been placed in the public domain.

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Thank you,
Christian