@node Verbose, Version, User, Commands

@iftex
@syntax Verbose.
@end iftex
@example
Syntax: VERBOSE INTEGER
@end example
@pindex Verbose
@findex diagnostics, verbose

Make SM produce output on what it is doing if @code{INTEGER} is > 0.
Setting VERBOSE to 0 is a way of only listing `important' (non-system) macros,
and generally getting a little peace and quiet. It has the considerable
disadvantage that you can think that you are reading data from files, while
actually something is wrong. For this reason the default value is 1. A value
of 2 or more is basically useful for debugging. If you get some nondescript
syntax error and don't know where it is coming from, VERBOSE of 3 or 4 will
trace your programme, and should help find the problem. The original error
message will tell you which macro SM thinks it is processing
when the error occurred but it will be wrong if the macro
had been fully scanned when the error is detected. In this case it will
report a parent of the current macro. The reason for this behaviour is
related to why @code{RETURN} can return from the wrong place
(@pxref{Command Internals}).
@findex syntax error, tracking down

If you want to know the current value of VERBOSE you can use the
SHOW command (actually a macro), or try
@example
DEFINE verbose DELETE echo Verbose: $verbose
@end example
@noindent
which is (of course) what SHOW does anyway.
@findex internal variables, verbose

If verbose is one or more SM will:
@itemize @bullet
@item
Classify vectors as number- or string-valued
@item
Complain about things like division by zero, and logs of negative
numbers the first time that they occur in a given expression
@item
Include all macros in macro listings, even those starting ##
@item
Indicate line where arithmetical errors occur
@item
Indicate the number of the X11 device that you switch to with @code{-dev} [+-]
@item
List all non-printing key-bindings with LIST EDIT
@item
Note more than 40 curve crossings in SHADE
@item
Notify user when a @ctrl{C} stopped the production of a hardcopy
@item
Output a little extra about RESTORE and SAVE
@item
Print lines beginning # while reading macro files
@item
Provide some context with APROPOS on help files
@item
Realise that a WINDOW number is out of range
@item
Report which lines are read from a file using READ
@item
Remind you that mixing LOCATION with WINDOW confuses people
@item
Suggest that you change LOCATION to make room for axis labels
@item
Tell a bit about format and size of IMAGE files
@item
Warn about zero-length vectors
@item
Whinge about missing fields with DEFINE var READ # #
@end itemize

@itemize @bullet
if @code{INTEGER} is two or greater, then also :
@item
Announce when the do, foreach, input, or macro stacks are extended
@item
Complain if an environment or SM variable is not defined
@item
Echo lines in data files that start with #
@item
Include `internal' variables in LIST DEFINE output
@item
Inform you when it seeks to a line in a data file
@item
List all key-bindings with LIST EDIT
@item
Note attempts to `unput' off bottoms of buffers (this is related to the
implementation of macros and variables)
@item
Point out attempts to delete local variables and vectors
@item
Print the fraction of axes covered by the tick labels
@item
Prompt for variables, even if they are on the macro buffer
@item
Protest if you reference an undefined history number
@item
Remark if a variable is referenced in a graphcap SY string, but not provided
@item
Remind you that only a finite number of KEY commands can be processed
@item
Repeat complaint about things like division by zero, and logs of
negative numbers every time that they occur
@item
Report vectors of different lengths in PRINT
@item
Say when a vector is used as a scalar.
@item
Tell you when vectors are redefined.
@item
Write a note when it finds out-of-range values while contouring IMAGE files.
@end itemize

if @code{INTEGER} is three or greater, then also :

@itemize @bullet
@item
List each macro name just prior to expansion.
@end itemize

if @code{INTEGER} is four or greater, then also :
@itemize @bullet
@item
Print each token as it is recognised along with its text. The number in
@item
column 1 is the value of `noexpand', the level of nesting of @{@} loops.
@item
Show expansions of variables.
@end itemize

if @code{INTEGER} is five or greater, then also :
@itemize @bullet
@item
Print the contents of DO, FOREACH, IF, and MACRO command lists.
@item
Prompt for DEFINEing variables and the values of multi-word variables.
@end itemize


If you set a negative verbosity, then if the parser was compiled
with DEBUG defined, you'll get a veritable torrent of debugging
information. Use another negative VERBOSE command to turn it off again.