Re: [TCLCORE] New tip #722

[Donald G P. <don...@ni...>]

Revising the behavior of an existing subcommand raises worries ( at least )
about compatibility.

Consider proposing a new subcommand instead.

On 5/19/25 01:40, Christian Werner wrote:
> Hello all,
>
> (posted again in case I've sent it with the wrong account)
>
> please could some tip fossil maintainer add the following tip.
>
> ---8><---8><---
>
> # 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.
>
> ---8><---8><---
>
> Thank you,
> Christian
>
>
>
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-- 
| Don Porter            Applied and Computational Mathematics Division |
| don...@ni...             Information Technology Laboratory |
| http://math.nist.gov/~DPorter/                                  NIST |
|______________________________________________________________________|