LaTeXML::Common::Error(3)

NAME
"LaTeXML::Common::Error" - Error and Progress Reporting and Logging support.

DESCRIPTION
"LaTeXML::Common::Error" does some simple stack analysis to generate more informative, readable, error messages for LaTeXML. Its routines are used by the error reporting methods from LaTeXML::Global, namely "Warn", "Error" and "Fatal".

The general idea is that a minimal amount should be printed to STDERR (possibly with colors, spinners, etc if it is a terminal), and more complete information is printed to a log file. Neither of these are enabled, by default; see below.

"SetVerbosity($verbosity);"
    Controls the verbosity of output to the terminal; default is 0, higher gives more information, lower gives less. A verbosity less than 0 inhibits all output to STDERR.

"UseSTDERR(); ... UseSTDERR(undef);"
    "UseSTDERR();" Enables and initializes STDERR to accept messages. If this is not called, there will be no output to STDERR. "UseSTDERR(undef);" disables STDERR from further messages.

"UseLog($path, $append); ... UseLog(undef);"
    "UseLog($path, $append);" opens a log file on the given path. If $append is true, this file will be appended to, otherwise, it will be created initially empty. If this is not called, there will be no log file. "UseLog(undef);" disables and closes the log file.

  Error Reporting
The Error reporting functions all take a similar set of arguments, the differences are in the implied severity of the situation, and in the amount of detail that will be reported.

The $category is a string naming a broad category of errors, such as "undefined". The set is open-ended, but see the manual for a list of recognized categories. $object is the object whose presence or lack caused the problem.

$where indicates where the problem occurred; passs in the $gullet or $stomach if the problem occurred during expansion or digestion; pass in a document node if it occurred there. A string will be used as is; if an undefined value is used, the error handler will try to guess.

The $message should be a somewhat concise, but readable, explanation of the problem, but ought to not refer to the document or any "incident specific" information, so as to support indexing in build systems. @details provides additional lines of information that may be indident specific.

"Fatal($category,$object,$where,$message,@details);"
    Signals an fatal error, printing $message along with some context. In verbose mode a stack trace is printed.

"Error($category,$object,$where,$message,@details);"
    Signals an error, printing $message along with some context. If in strict mode, this is the same as Fatal(). Otherwise, it attempts to continue processing..

"Warn($category,$object,$where,$message,@details);"
    Prints a warning message along with a short indicator of the input context, unless verbosity is quiet.

"Info($category,$object,$where,$message,@details);"
    Prints an informational message along with a short indicator of the input context, unless verbosity is quiet.

  Progress Reporting

"Note($message);"
    General status message, printed whenever verbosity at or above 0, to both STDERR and the Log file (when enabled).

"NoteLog($message);"
    Prints a status message to the Log file (when enabled).

"NoteSTDERR($message);"
    Prints a status message to the terminal (STDERR) (when enabled).

"ProgressSpinup($stage);"
    Begin a processing stage, which will be ended with "ProgressSpindown($stage)"; This prints a message to the log such as "(stage... runtime)", where runtime is the time required. In conjunction with "ProgressStep()", creates a progress spinner on STDERR.

"ProgressSpinup($stage);"
    End a processing stage bugin with "ProgressSpindown($stage);".

"ProgressStep();"
    Steps a progress spinner on STDERR.

  Debugging
Debugging statements may be embedded throughout the program. These are associated with a feature keyword. A given feature is enabled using the command-line option "--debug=feature".

"Debug($message) if $LaTeXML::DEBUG{$feature}"
    Prints $message if debugging has been enabled for the given feature.

"DebuggableFeature($feature,$description)"
    Declare that $feature is a known debuggable feature, and give a description of it.

"CheckDebuggable()"
    A untility to check and report if all requested debugging features actually have debugging messages declared.

  Internal Functions
No user serviceable parts inside. These symbols are not exported.

"$string = LaTeXML::Common::Error::generateMessage($typ,$msg,$lng,@more);"
    Constructs an error or warning message based on the current stack and the current location in the document. $typ is a short string characterizing the type of message, such as "Error". $msg is the error message itself. If $lng is true, will generate a more verbose message; this also uses the VERBOSITY set in the $STATE. Longer messages will show a trace of the objects invoked on the stack, @more are additional strings to include in the message.

"$string = LaTeXML::Common::Error::stacktrace;"
    Return a formatted string showing a trace of the stackframes up until this function was invoked.

"@objects = LaTeXML::Common::Error::objectStack;"
    Return a list of objects invoked on the stack. This procedure only considers those stackframes which involve methods, and the objects are those (unique) objects that the method was called on.

AUTHOR
Bruce Miller <bruce.miller@nist.gov>

COPYRIGHT
Public domain software, produced as part of work done by the United States Government & not subject to copyright in the US.