debug(3tcl) debug narrative debug(3tcl)
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NAME
debug - debug narrative - core
SYNOPSIS
package require Tcl 8.5
package require debug ?1.0.6?
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
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DESCRIPTION
Debugging areas of interest are represented by 'tags' which have inde-
pendently settable levels of interest (an integer, higher is more de-
tailed).
API
debug.tag message ?level?
For each known tag the package creates a command with this sig-
nature 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 arbi-
trarily complex narrative in code without unnecessarily evaluat-
ing 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 ex-
ist, 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 de-
faults 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 mes-
sages.
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 regis-
tered, 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 acti-
vating 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 mes-
sages.
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 regis-
tered, 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 how-
ever).
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.
When proposing code changes, please provide unified diffs, i.e the out-
put of diff -u.
Note further that attachments are strongly preferred over inlined
patches. Attachments can be made by going to the Edit form of the
ticket immediately after its creation, and then using the left-most
button in the secondary navigation bar.
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>
tcllib 1.0.6 debug(3tcl)