LEFTY(1)                                                                                                                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 cased 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 createwid-
              get call. The default file name is out.ps.

       -V     Prints the version.

SEE ALSO
       lefty user guide.



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