This command manages file scan contexts. A scan context is a collection of
regular expressions and commands to execute when that regular expression
matches a line of the file. A context may also have a single default match,
to be applied against lines that do not match any of the regular expressions.
Multiple scan contexts may be defined and they may be reused on multiple files.
A scan context is identified by a context handle. The scancontext
the following forms:
Creates a new scan context. The scanmatch command is used to define
patterns in the context. A context handle is returned, which the Tcl
programmer uses to refer to the newly created scan context in calls
to the Tcl file scanning commands.
Deletes the scan context identified by contexthandle, and frees all
match statements and compiled regular expressions associated with the