From AOLserver Wiki
Jump to navigation Jump to search
    AIP: 1
  Title: AOLserver Improvement Proposal Guidelines
Version: 1.0
Authors: Dossy Shiobara <dossy at panoptic dot com>
         incl. [1].
  State: Draft 
   Type: Process 
   Vote: Pending 
Created: 04 September 2003


This document describes and defines the editorial process a TCT document (TIP) has to go through before accepted as official.

What is a TIP?

TIP stands for Tcl Improvement Proposal. A TIP is a design document providing information to the Tcl community, or describing a new feature for Tcl. The TIP should provide a concise technical specification of the feature and a rationale for the feature.

We intend TIPs to be the primary mechanisms for proposing new features, for collecting community input on an issue, and for documenting the design decisions that have gone into Tcl. The TIP author is responsible for building consensus within the community and documenting dissenting opinions.

Because the TIPs are maintained as text files under revision control, their history is the historical record of the feature proposal. This historical record is available by the normal (CVS?) commands for retrieving older revisions. For those without direct access to the CVS tree, you can browse the current and past TIP revisions via .

Further details on the arguments behind the evolution of the TIP concept and formatting can be found in the archive of the tclcore mailing list at .

Kinds of TIPs

There are three kinds of TIPs. A project TIP describes a new (or significantly updated) feature or implementation for Tcl. An informative TIP describes a Tcl design issue, or provides general guidelines or information to the Tcl community, but does not propose a new feature. A process TIP is like an informative TIP but the provided guidelines are mandatory in a certain context (as specified in the TIP itself).

Voting by the TCT as per the charter (see TIP #0) is required to make a project or process TIP official.

TIP Workflow

The TIP editor, Donal K. Fellows <fellowsd at cs dot man dot ac dot uk> pro tem, assigns numbers for each TIP and changes its status.

Everyone in the community can submit a TIP to the TIP editor. It should contain at least a proposed title and a rough, but fleshed out, draft of the TIP.

If the TIP editor approves, he will assign the TIP a number, label it as either project, process or informational, give it status Draft, and create and check-in the initial draft of the TIP. The TIP editor will not unreasonably deny a TIP. Reasons for denying TIP status include gross malformatting, inappropriate copyright, duplication of effort, being technically unsound, or not in keeping with the Tcl philosophy; the TCT and after that John Ousterhout <ouster at pacbell dot net> is the final arbitrator of the latter, as defined in the charter (TIP #0).

Discussion concerning a TIP should initially be kept out of the tclcore and tct mailing lists. Instead, comments should be sent to, and collected by, the TIP author, who has the responsibility to incorporate these comments into the document.

Note: It has been proposed to create a new mailing list for each TIP to handle its discussion. Rejection and finalization of the TIP closes the mailing list, but not the archive. Together with the CVS history a complete record of the development of a TIP will be available.

The authors of the TIP are responsible for writing the TIP and marshaling community support for it. The structure of a TIP is described in detail in TIP #3.

A project TIP consists of two parts, a design document and a reference implementation. The TIP should be reviewed and accepted before a reference implementation is begun, unless a reference implementation will aid people in studying the TIP. The implementation can be given in the form of code, patch, or URL to same - before it can be considered Final; small reference implementations may be placed inside the TIP itself, and large reference implementations should be held externally and linked to by reference (typically URL.)

Process and Informational TIPs do not need an implementation.

TIP authors are responsible for collecting community feedback on a TIP before submitting it for review (the creation of a TIP is a part of that review process.) However, wherever possible, long open-ended discussions on public mailing lists should be avoided. A better strategy is to encourage public feedback directly to the TIP author, who collects and integrates the comments back into the TIP.

Once the authors have completed a TIP, they must inform the Tcl Core Team that it is ready for review. TIPs are reviewed by the Tcl Core Team and (for Project TIPs) the maintainers for the relevant parts of the core, who may accept or reject a TIP or send it back to the author(s) for revision (as detailed in TIP #0.) The acceptance or rejection of a TIP will cause its state to be changed accordingly to Accepted or Rejected.

Once a TIP requiring a reference implementation has been accepted, the reference implementation must be completed. When the reference implementation is complete and accepted by the TCT (who can reject it if they feel the implementation would damage the rest of the core) the status will be changed to Final.

A TIP can also be assigned status Deferred. The TIP author or the editor can assign the TIP this status when no progress is being made on the TIP. Once a TIP is deferred, the TIP editor can re-assign it to Draft status.

A TIP can also be Withdrawn by the author. Perhaps after all is said and done, the author believes it was not a good idea. It is still important to have a record of this fact. It is expected that Accepted TIPs will only be withdrawn very rarely, and Final TIPs only under exceptional circumstances.

TIP workflow is as follows:


Some informative TIPs may also have a status of Active if they are never meant to be completed. For example: TIP #1.

What belongs in a successful TIP?

Each TIP should have the following parts:

1. Title - a short, descriptive title.

2. Author(s) - names and contact info (email addresses) for each author.

3. Abstract - a short (typically <200 word) description of the technical issue being addressed.

4. Copyright/public domain - Each TIP must either be explicitly labelled in the public domain (the preferred 'license') or the Open Publication License ( It is recommended that this be done by making the last section of the document be a copyright heading, with the body describing what copyright (if any) the document is released under.

5. Specification - Project TIPs should have a technical specification that should describe the syntax and semantics of any new language feature. The specification should be detailed enough to allow (competing) interoperable implementations for any of the current Tcl platforms.

6. Rationale - The rationale fleshes out the specification by describing what motivated the design and why particular design decisions were made. It should describe alternate designs that were considered and related work, e.g. how the feature is supported in other languages.

The rationale should provide evidence of consensus within the community and discuss important objections or concerns raised during discussion.

7. Reference Implementation - The reference implementation must be completed before any TIP requiring such is given status Final, but it need not be completed before the TIP is accepted. It is better to finish the specification and rationale first and reach consensus on it before writing code.

The final implementation must include test code and documentation appropriate for either the Tcl language reference or the standard library reference.

TIP Style

TIPs are written in plain ASCII text with an RFC822-like header and embedded sequences suitable for Wiki-like processing as indicated in TIP #3.

There are Tcl scripts that convert the TIP into HTML for viewing on the web. Scripts for producing other formats are available too, for example LaTeX and plain ASCII.

Sample Project TIP

(With thanks to William H. Duquette <William dot H dot Duquette at jpl dot nasa dot gov> for suggesting this.) Note that the TIP Editor is responsible for allocating TIP numbers, so you can leave that unfilled.

TIP:           ???
Title:         The TIP Title as Plain Text
Version:       $Revision: 1.21 $
Author:        Author Name <>
State:         Draft
Type:          Project
Tcl-Version:   8.4
Vote:          Pending
Created:       31-Feb-1999
~ Abstract
This is an example of how to write a simple project TIP.  This is the
abstract which should consist of a single paragraph of under 200
words.  If you need more than this, you should stop and think about
writing a real abstract, not a whole section!  :^)
~ Some Sections
Yada yada yada.  Look at the sources to the various TIPs for tricks
on how to do various things.  Note that for complete legal safety,
you must specify what copyright is used.  We prefer public domain,
as it allows others (notably the TIP editor(s)) to maintain the TIP
as necessary without having to seek permission.
I also prefer to make sure TIP and section titles are capitalized
according to the usual rules of English.
~ Copyright
This document has been placed in the public domain.

A more complex example is TIP #7 by Kevin Kenny <kennykb at acm dot org> (the source is at and which includes demonstrations of how to use advanced features like figures and verbatim text. His is a very high quality TIP though, and it has been though several revisions; don't feel too put off if your first attempt isn't quite as good...


For preference, patches to Tcl should be stored separately on another website or submitted as a separate file. This is because (quite rightly) the news:comp.lang.tcl.announce moderator does not allow patches to be posted on that newsgroup. If you want a patch to be incorporated into the archive, please contact the TIP Editor.