tokenizer.pro

经典的基于Context-Free_Grammer 的语法分析器。

% Author: Ying Tao, Department of Biomedical Informatics, Columbia University
% Date: 12/7/2005
:-module(tokenizer,[tokenize/2]).

tokenize(Str,List):- scanStr(Str,0,'',[],List),!.

scanStr(Str,L,Wlist,List,List1):- string_length(Str,L),string_to_atom(Wlist,Last),append(List,[Last],List1),!.
scanStr(Str,L,Sw,Wlist,List):-    sub_string(Str,L,1,_,X),

                      string_to_list(X,Xl),
                      (( Xl = " ")->
                       (     string_to_atom(Sw,Nwa),
                             append(Wlist,[Nwa],NWlist),
                             L1 is L +1,
                             scanStr(Str,L1,'',NWlist,List)
                       )
                        ;
                       ( string_concat(Sw,X,Nw),
                         L1 is L +1,
                         scanStr(Str,L1,Nw,Wlist,List)
                       )).