Author:		Thomas Perschak <tombert.group@live.at>
State:		Draft
Type:		Project
Tcl-Version:	8.7
Vote:		Pending
Created:	07-Jun-2013
Post-History:
Keywords:	Tcl, time, millisecond resolution

Abstract

This TIP describes a change to clock format to allow it to handle timestamps with sub-second accuracy.

Rationale

Currently, the clock format accepts only integer numbers for clock formatting. Since the clock milliseconds command was introduced in Tcl 8.5, this limitation seems a bit restrictive.

In particular, the timestamp column in a number of databases (e.g., http://www.postgresql.org/docs/9.1/static/datatype-datetime.html\) handles high-resolution timestamps by allowing full ISO 8601 times, which look like "04:05:06.789"; this would simplify database write operations.

Proposal

The clock format command should accept floating point values for timestamps.

Another format letter should be added to clock format which puts the milliseconds into the output string; the millisecond value should not be written unless explicitly requested.

Copyright

This document has been placed in the public domain.