Provided by: tcllib_1.17-dfsg-1_all 
NAME
debug - debug narrative - core
SYNOPSIS
package require Tcl 8.5
package require debug ?1.0.5?
debug.tag message ?level?
debug 2array
debug define tag
debug header text
debug level tag ?level? ?fd?
debug names
debug off tag
debug on tag
debug parray arrayvarname
debug pdict dict
debug hexl data ?prefix?
debug nl
debug tab
debug prefix tag ?text?
debug setting (tag level) ... ?fd?
debug suffix tag ?text?
debug trailer text
_________________________________________________________________________________________________
DESCRIPTION
Debugging areas of interest are represented by 'tags' which have independently settable
levels of interest (an integer, higher is more detailed).
API
debug.tag message ?level?
For each known tag the package creates a command with this signature the user can
then use to provide the debug narrative of the tag. The narrative message is
provided as a Tcl script whose value is substed in the caller's scope if and only
if the current level of interest for the tag matches or exceeds the call's level of
detail. This is useful, as one can place arbitrarily complex narrative in code
without unnecessarily evaluating it.
See methods level and setting for querying and manipulating the current level of
detail for tags.
The actually printed text consists of not only the message, but also global and
tag-specific prefix and suffix, should they exist, with each line in the message
having the specified headers and trailers.
All these parts are substableTcl scripts, which are substituted once per message
before assembly.
debug 2array
This method returns a dictionary mapping the names of all debug tags currently
known to the package to their state and log level. The latter are encoded in a
single numeric value, where a negative number indicates an inactive tag at the
level given by the absolute value, and a positive number is an active tag at that
level.
See also method settings below.
debug define tag
This method registers the named tag with the package. If the tag was not known
before it is placed in an inactive state. The state of an already known tag is left
untouched.
The result of the method is the empty string.
debug header text
This method defines a global substable Tcl script which provides a text printed
before each line of output.
Note how this is tag-independent.
Further note that the header substitution happens only once per actual printed
message, i.e. all lines of the same message will have the same actual heading text.
The result of the method is the specified text.
debug level tag ?level? ?fd?
This method sets the detail-level for the tag, and the channel fd to write the tags
narration into. The level is an integer value >= 0 defaulting to 1. The channel
defaults to stderr.
The result of the method is the new detail-level for the tag.
debug names
This method returns a list containing the names of all debug tags currently known
to the package.
debug off tag
This method registers the named tag with the package and sets it inactive.
The result of the method is the empty string.
debug on tag
This method registers the named tag with the package, as active.
The result of the method is the empty string.
debug parray arrayvarname
This is a convenience method formatting the named array like the builtin command
parray, except it returns the resulting string instead of writing it directly to
stdout.
This makes it suitable for use in debug messages.
debug pdict dict
This is a convenience method formatting the dictionary similarly to how the builtin
command parray does for array, and returns the resulting string.
This makes it suitable for use in debug messages.
debug hexl data ?prefix?
This is a convenience method formatting arbitrary data into a hex-dump and returns
the resulting string.
This makes it suitable for use in debug messages.
Each line of the dump is prefixed with prefix. This prefix defaults to the empty
string.
debug nl
This is a convenience method to insert a linefeed character (ASCII 0x0a) into a
debug message.
debug tab
This is a convenience method to insert a TAB character (ASCII 0x09) into a debug
message.
debug prefix tag ?text?
This method is similar to the method header above, in that it defines substable Tcl
script which provides more text for debug messages.
In contrast to header the generated text is added to the user's message before it
is split into lines, making it a per-message extension.
Furthermore the script is tag-dependent.
In exception to that, a script for tag :: is applied to all messages.
If both global and tag-dependent prefix exist, both are applied, with the global
prefix coming before the tag-dependent prefix.
Note that the prefix substitution happens only once per actual printed message.
The result of the method is the empty string.
If the tag was not known at the time of the call it is registered, and set
inactive.
debug setting (tag level) ... ?fd?
This method is a multi-tag variant of method level above, with the functionality of
methods on, and off also folded in.
Each named tag is set to the detail-level following it, with a negative level
deactivating the tag, and a positive level activating it.
If the last argument is not followed by a level it is not treated as tag name, but
as the channel all the named tags should print their messages to.
The result of the method is the empty string.
debug suffix tag ?text?
This method is similar to the method trailer below, in that it defines substable
Tcl script which provides more text for debug messages.
In contrast to trailer the generated text is added to the user's message before it
is split into lines, making it a per-message extension.
Furthermore the script is tag-dependent.
In exception to that, a script for tag :: is applied to all messages.
If both global and tag-dependent suffix exist, both are applied, with the global
suffix coming after the tag-dependent suffix.
Note that the suffix substitution happens only once per actual printed message.
The result of the method is the empty string.
If the tag was not known at the time of the call it is registered, and set
inactive.
debug trailer text
This method defines a global substable Tcl script which provides a text printed
after each line of output (before the EOL however).
Note how this is tag-independent.
Further note that the trailer substitution happens only once per actual printed
message, i.e. all lines of the same message will have the same actual trailing
text.
The result of the method is the specified text.
BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain bugs and other
problems. Please report such in the category debug of the Tcllib Trackers
[http://core.tcl.tk/tcllib/reportlist]. Please also report any ideas for enhancements you
may have for either package and/or documentation.
KEYWORDS
debug, log, narrative, trace
CATEGORY
debugging, tracing, and logging
COPYRIGHT
Copyright (c) 200?, Colin McCormack, Wub Server Utilities
Copyright (c) 2012-2014, Andreas Kupries <andreas_kupries@users.sourceforge.net>