REFERENCES

   1 From phr Tue Jul  8 10:36:19 1986
   2 Date: Tue, 8 Jul 86 00:52:24 EDT
   3 From: phr (Paul Rubin)
   4 To: riferguson%watmath.waterloo.edu@CSNET-RELAY.ARPA, tower
   5 Subject: Re:  Bison documentation?
   6
   7 The main difference between Bison and Yacc that I know of is that
   8 Bison supports the @N construction, which gives you access to
   9 the starting and ending line number and character number associated
  10 with any of the symbols in the current rule.
  11
  12 Also, Bison supports the command `%expect N' which says not to mention
  13 the conflicts if there are N shift/reduce conflicts and no reduce/reduce
  14 conflicts.
  15
  16 The differences in the algorithms stem mainly from the horrible
  17 kludges that Johnson had to perpetrate to make Yacc fit in a PDP-11.
  18
  19 Also, Bison uses a faster but less space-efficient encoding for the
  20 parse tables (see Corbett's PhD thesis from Berkeley, "Static
  21 Semantics in Compiler Error Recovery", June 1985, Report No. UCB/CSD
  22 85/251), and more modern technique for generating the lookahead sets.
  23 (See "Efficient Construction of LALR(1) Lookahead Sets" by F. DeRemer
  24 and A. Pennello, in ACM TOPLS Vol 4 No 4, October 1982.  Their
  25 technique is the standard one now.)
  26
  27         paul rubin
  28         free software foundation
  29
  30