module brcpg.   
 
% Bounded Right Context Parser Generator tests
 
% some small grammars for experimentation

 
terminal X :- 
  oncememb X [bofs,eofs,plust,eqt,timest,lparen,rparen,(const V),(id S)].
non_terminal X :- oncememb X [sx,ex,tx,fx,lx,rx].
 
% sx ==> [ex] must ALWAYS be first production!!
 
ntnum 4.  % number of non_terminals for gammar being considered.
 
cfg    % BRC(1,1), but not simple BRC (SR conflict)
[ 
  rule ( sx ==> [ex] ) true,
  rule ( ex ==> [lx,eqt,rx] ) true,
  rule ( ex ==> [rx] ) true,
  rule ( lx ==> [timest,rx] ) true,
  rule ( lx ==> [const K] ) true,
  rule ( rx ==> [lx] ) true
] :- !.
 
cfg    % really ambiguous gammar
[
  rule (sx ==> [ex]) true,  
  rule (ex ==> [const V]) true,
  rule (ex ==> [ex,timest,ex]) true,
  rule (ex ==> [ex,plust,ex]) true,
  rule (ex ==> [ex,eqt,ex]) true
] :- !.
binaryop plust ex ex "left" 3.
binaryop timest ex ex "left" 2.
binaryop eqt ex ex "left" 4.
 
 
cfg    % ambiguous w/ sr-conflict
[
  rule (sx ==> [ex]) true,
  rule (ex ==> [id X]) true,
  rule (ex ==> [ex,ex]) true
] :- !.
 
cfg    % SBRC example
[
  rule ( sx ==> [ex] ) true,
  rule ( ex ==> [ex,plust,tx] ) true,
  rule ( ex ==> [tx] ) true,
  rule ( tx ==> [tx,timest,fx] ) true,
  rule ( tx ==> [fx] ) true,
  rule ( fx ==> [lparen,ex,rparen] ) true,
  rule ( fx ==> [const V] ) true
] :- !.
 
cfg     % BRC(1,1) and LR(1) and not SBRC or LALR (from Dragon book)
[
  rule ( sx ==> [ex] ) true,
  rule ( ex ==> [id "a", tx, id "d"]) true,
  rule ( ex ==> [id "a", fx, id "e"]) true,
  rule ( ex ==> [id "b", tx, id "e"]) true,
  rule ( ex ==> [id "b", fx, id "d"]) true,
  rule ( tx ==> [id "c"] ) true,
  rule ( fx ==> [id "c"] ) true
] :- !.
 
cfg    % ambiguous w/ rr-conflict
[
  rule (sx ==> [ex]) true,
  rule (ex ==> [timest]) true,
  rule (ex ==> [ex,timest]) true,
  rule (ex ==> [plust,ex,timest]) true
] :- !.

freshcopy T T.