1LEFTY(1)                    General Commands Manual                   LEFTY(1)
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NAME

6       lefty - A Programmable Graphics Editor
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SYNOPSIS

9       lefty [ options ] [ file ]
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DESCRIPTION

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

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

38       -x     Instructs the editor to exit after processing file.
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40       -e <expression>
41              <expression> is parsed and executed.
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43       -el <num>
44              Set  error  reporting  level.  The  default value is 0.  0 never
45              prints any messages.  1 prints severe errors, such as trying  to
46              return  from  a  non function.  2 is the most useful: it reports
47              function calls that cannot be executed, either because there  is
48              no  function,  or  because of argument mismatches.  3 also warns
49              about bad variable names.  4,5 warn about  expressions  that  do
50              not  return  a value. Only level 1 messages are real errors. The
51              rest arise from legal lefty statements, but may be cased by some
52              logic errors.
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54       -sd <num>
55              Specifies  how  much of the stack to show, when an error message
56              is to be printed. The default value is 2.  With 0,  no  part  of
57              the stack is shown. With 1, only the top stack frame is printed.
58              With 2, the full stack is printed.
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60       -sb <num>
61              Specifies how much of each function in the stack to  show,  when
62              an error message is to be printed. The default value is 2.  With
63              0, no part of the function is  shown.  With  1,  only  the  line
64              around  the  error is printed. With 2, the full function body is
65              printed.
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67       -df <string>
68              Sets the default font. This font is used  whenever  a  requested
69              font  cannot  be  found.  The  string must be a legal X font. If
70              string is '', lefty will draw small boxes instead of text.
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72       -ps <file>
73              Specifies a default file name for postscript files. This name is
74              used  when  no  name  is specified in the createwidget call. The
75              default file name is out.ps.
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77       -V     Prints the version.
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SEE ALSO

80       lefty user guide.
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