dlg



dlg(1)                        PCCTS Manual Pages                        dlg(1)




NAME

       dlg - DFA Lexical Analyzer Generator


SYNTAX

       dlg [options] lexical_spec [output_file]


DESCRIPTION

       dlg is a tool that produces fast deterministic finite automata for rec-
       ognizing regular expressions in input.


OPTIONS

       -CC    Generate C++ output.  The output_file is not specified  in  this
              case.

       -C[ level]
              Where  level  is  the  compression level used.  0 indications no
              compression, 1 removes all unused characters from the transition
              from table, and 2 maps equivalent characters into the same char-
              acter classes.  It is suggested that level -C2 is used, since it
              will significantly reduce the size of the dfa produced for lexi-
              cal analyzer.

       -m     Produces the header file for the lexical mode with a name  other
              than the default name of "mode.h".

       -i     An  interactive,  or  as interactive as possible, parser is pro-
              duced.  A character is only obtained  when  required  to  decide
              which  state to go to.  Some care must be taken to obtain accept
              states that do not require look ahead at the next  character  to
              determine  if  that  is  the stop state.  Any regular expression
              with a Kleene closure  at  the  end  is  guaranteed  to  require
              another character of look ahead.

       -cl class
              Specify  a  class  name  for  DLG  to  generate.  The default is
              DLGLexer.

       -ci    The automaton will treat upper and lower case characters identi-
              cally.  This is accomplished in the automaton; the characters in
              the lexical buffer are unmodified.

       -cs    Upper and lower case characters are treated as  distinct.   This
              is the default.

       -o dir Directory  where  output files should go (default=".").  This is
              very nice for keeping the source directory clear  of  ANTLR  and
              DLG spawn.

       -Wambiguity
              Warns  if  more than one regular expression could match the same
              character sequence.   The  warnings  give  the  numbers  of  the
              expressions  in the dlg lexical specification file.  The number-
              ing of the expressions starts at one.  Multiple warnings may  be
              print for the same expressions.

       -      Used  in  place  of  file names to get input from standard in or
              send output to standard out.


SPECIAL CONSIDERATIONS

       Dlg works...  we think.  There is no implicit  guarantee  of  anything.
       We reserve no legal rights to the software known as the Purdue Compiler
       Construction Tool Set (PCCTS) — PCCTS is  in  the  public  domain.   An
       individual  or  company may do whatever they wish with source code dis-
       tributed with PCCTS or the  code  generated  by  PCCTS,  including  the
       incorporation  of  PCCTS,  or its output, into commercial software.  We
       encourage users to develop software with PCCTS.   However,  we  do  ask
       that  credit is given to us for developing PCCTS.  By "credit", we mean
       that if you incorporate our source code into one of your programs (com-
       mercial  product,  research project, or otherwise) that you acknowledge
       this fact somewhere in the documentation, research report,  etc...   If
       you  like  PCCTS and have developed a nice tool with the output, please
       mention that you developed it using PCCTS.  As long as these guidelines
       are followed, we expect to continue enhancing this system and expect to
       make other tools available as they are completed.


FILES

       mode.h , dlgauto.h , dlgdef.h


SEE ALSO

       antlr(1), pccts(1)


BUGS

DLG                               April 1994                            dlg(1)

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