Daniel@0: .TH LEFTY 1
Daniel@0: .SH NAME
Daniel@0: lefty \- A Programmable Graphics Editor
Daniel@0: .SH SYNOPSIS
Daniel@0: .B lefty
Daniel@0: [
Daniel@0: .I options
Daniel@0: ] [
Daniel@0: .I file
Daniel@0: ]
Daniel@0: .SH DESCRIPTION
Daniel@0: .B lefty
Daniel@0: is a two-view graphics editor for technical pictures. This editor has
Daniel@0: no hardwired knowledge about specific picture layouts or editing operations.
Daniel@0: Each picture is described by a program that contains functions to draw the
Daniel@0: picture and functions to perform editing operations that are appropriate for
Daniel@0: the specific picture. Primitive user actions, like mouse and keyboard events,
Daniel@0: are also bound to functions in this program. Besides the graphical view of the
Daniel@0: picture itself, the editor presents a textual view of the program that
Daniel@0: describes the picture. Programmability and the two-view interface allow the
Daniel@0: editor to handle a variety of pictures, but are particularly useful for
Daniel@0: pictures used in technical contexts, e.g., graphs and trees. Also,
Daniel@0: .B lefty
Daniel@0: can communicate with other processes. This feature allows it to use existing
Daniel@0: tools to compute specific picture layouts and allows external processes to use
Daniel@0: the editor as a front end to display their data structures graphically.
Daniel@0: .SH USAGE
Daniel@0: The file name is optional. It may be
Daniel@0: .BR - ,
Daniel@0: for reading from standard input.
Daniel@0: .B lefty
Daniel@0: uses two environment variables,
Daniel@0: .B LEFTYPATH
Daniel@0: and
Daniel@0: .BR LEFTYOPTIONS .
Daniel@0: .B LEFTYPATH
Daniel@0: is a colon separated list of directories. When
Daniel@0: .B lefty
Daniel@0: tries to open a file, it searches that path for the file. When
Daniel@0: .B lefty
Daniel@0: tries to start up another process, it searches
Daniel@0: .B LEFTYPATH
Daniel@0: first, then the standard
Daniel@0: .B PATH
Daniel@0: variable.
Daniel@0: .B LEFTYOPTIONS
Daniel@0: can be used to set specific options. Options specified on the command line
Daniel@0: override options set through this variable.
Daniel@0: .SH OPTIONS
Daniel@0: .TP
Daniel@0: .B -x
Daniel@0: Instructs the editor to exit after processing
Daniel@0: .BR file .
Daniel@0: .TP
Daniel@0: .B "-e <expression>"
Daniel@0: .B <expression>
Daniel@0: is parsed and executed.
Daniel@0: .TP
Daniel@0: .B -el <num>
Daniel@0: Set error reporting level. The default value is
Daniel@0: .BR 0 .
Daniel@0: .B 0
Daniel@0: never prints any messages.
Daniel@0: .B 1
Daniel@0: prints severe errors, such as trying to return from a non function.
Daniel@0: .B 2
Daniel@0: is the most useful: it reports function calls that cannot be executed, either
Daniel@0: because there is no function, or because of argument mismatches.
Daniel@0: .B 3
Daniel@0: also warns about bad variable names.
Daniel@0: .B 4,5
Daniel@0: warn about expressions that do not return a value. Only level
Daniel@0: .B 1
Daniel@0: messages are real errors. The rest arise from legal
Daniel@0: .B lefty
Daniel@0: statements, but may be cased by some logic errors.
Daniel@0: .TP
Daniel@0: .B "-sd <num>"
Daniel@0: Specifies how much of the stack to show, when an error message is to be
Daniel@0: printed. The default value is
Daniel@0: .BR 2 .
Daniel@0: With
Daniel@0: .BR 0 ,
Daniel@0: no part of the stack is shown. With
Daniel@0: .BR 1 ,
Daniel@0: only the top stack frame is printed. With
Daniel@0: .BR 2 ,
Daniel@0: the full stack is printed.
Daniel@0: .TP
Daniel@0: .B "-sb <num>"
Daniel@0: Specifies how much of each function in the stack to show, when an error message
Daniel@0: is to be printed. The default value is
Daniel@0: .BR 2 .
Daniel@0: With
Daniel@0: .BR 0 ,
Daniel@0: no part of the function is shown. With
Daniel@0: .BR 1 ,
Daniel@0: only the line around the error is printed. With
Daniel@0: .BR 2 ,
Daniel@0: the full function body is printed.
Daniel@0: .TP
Daniel@0: .B "-df <string>"
Daniel@0: Sets the default font. This font is used whenever a requested font cannot be
Daniel@0: found. The string must be a legal X font. If string is
Daniel@0: .BR "''" ,
Daniel@0: .B lefty
Daniel@0: will draw small boxes instead of text.
Daniel@0: .TP
Daniel@0: .B "-ps <file>"
Daniel@0: Specifies a default file name for postscript files. This name is used when no
Daniel@0: name is specified in the
Daniel@0: .B createwidget
Daniel@0: call. The default file name is
Daniel@0: .BR out.ps .
Daniel@0: .TP
Daniel@0: .B -V
Daniel@0: Prints the version.
Daniel@0: .SH SEE ALSO
Daniel@0: .I lefty
Daniel@0: user guide.