LEFTY(1)                    General Commands Manual                   LEFTY(1)



NAME
       lefty - A Programmable Graphics Editor

SYNOPSIS
       lefty [ options ] [ file ]

DESCRIPTION
       lefty is a two-view graphics editor for technical pictures. This editor
       has no hardwired knowledge about specific picture layouts or editing
       operations.  Each picture is described by a program that contains
       functions to draw the picture and functions to perform editing
       operations that are appropriate for the specific picture. Primitive
       user actions, like mouse and keyboard events, are also bound to
       functions in this program. Besides the graphical view of the picture
       itself, the editor presents a textual view of the program that
       describes the picture. Programmability and the two-view interface allow
       the editor to handle a variety of pictures, but are particularly useful
       for pictures used in technical contexts, e.g., graphs and trees. Also,
       lefty can communicate with other processes. This feature allows it to
       use existing tools to compute specific picture layouts and allows
       external processes to use the editor as a front end to display their
       data structures graphically.

USAGE
       The file name is optional. It may be -, for reading from standard
       input.  lefty uses two environment variables, LEFTYPATH and
       LEFTYOPTIONS.  LEFTYPATH is a colon separated list of directories. When
       lefty tries to open a file, it searches that path for the file. When
       lefty tries to start up another process, it searches LEFTYPATH first,
       then the standard PATH variable.  LEFTYOPTIONS can be used to set
       specific options. Options specified on the command line override
       options set through this variable.

OPTIONS
       -x     Instructs the editor to exit after processing file.

       -e <expression>
              <expression> is parsed and executed.

       -el <num>
              Set error reporting level. The default value is 0.  0 never
              prints any messages.  1 prints severe errors, such as trying to
              return from a non function.  2 is the most useful: it reports
              function calls that cannot be executed, either because there is
              no function, or because of argument mismatches.  3 also warns
              about bad variable names.  4,5 warn about expressions that do
              not return a value. Only level 1 messages are real errors. The
              rest arise from legal lefty statements, but may be caused by
              some logic errors.

       -sd <num>
              Specifies how much of the stack to show, when an error message
              is to be printed. The default value is 2.  With 0, no part of
              the stack is shown. With 1, only the top stack frame is printed.
              With 2, the full stack is printed.

       -sb <num>
              Specifies how much of each function in the stack to show, when
              an error message is to be printed. The default value is 2.  With
              0, no part of the function is shown. With 1, only the line
              around the error is printed. With 2, the full function body is
              printed.

       -df <string>
              Sets the default font. This font is used whenever a requested
              font cannot be found. The string must be a legal X font. If
              string is '', lefty will draw small boxes instead of text.

       -ps <file>
              Specifies a default file name for postscript files. This name is
              used when no name is specified in the createwidget call. The
              default file name is out.ps.

       -V     Prints the version.

       -?     Prints the usage and exits.

SEE ALSO
       lefty user guide.



                                                                      LEFTY(1)
