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編譯器的虛擬yacc工具

The lex and yacc specification pairs in these directories are designed to
work with visual_yacc.

Each of the ch* files correspond to examples from the O'Reilly & Associates book
"lex & yacc" by John R. Levine, Tony Mason & Doug Brown.  Each has been modified
to work with visual_yacc.

Example gram corresponds to a pascal-oid language


To visualize a grammar, type
visual_yacc <fname>
  where <fname> corresponds to a lex file <fname>.l and a yacc file <fname>.y
  an optional -v flag can be used to see what is happening during
    creation.

This creates an executable.  The next step is to type:
<fname>.out < <input_string>
  where <input_string> is a file which contains some string in the language.  
  Sample input is given for each example (or will be in the near future).
  This command will cause a motif window to appear on your screen.  The
  visualization is controlled with several buttons:

  start -- start the visualization
  step  -- take a single step
  multi-step -- take a user-defined number of steps
  go  -- parse the entire input string
  quit -- end the visualization