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 edit-
       ing operations.	Each picture is described by a program that contains functions to draw the picture and functions to perform editing opera-
       tions 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  pic-
       ture. 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  exist-
       ing  tools  to compute specific picture layouts and allows external processes to use the editor as a front end to display their data struc-
       tures 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.

SEE ALSO

       lefty user guide.

																	  LEFTY(1)