1/* Part of dcgutils 2 Copyright 2012-2015 Samer Abdallah (Queen Mary University of London; UCL) 3 4 This program is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public License 6 as published by the Free Software Foundation; either version 2 7 of the License, or (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with this library; if not, write to the Free Software 16 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 17*/ 18 19:- module(dcg_shell, 20 [ dcgshell/2 21 , dcgshell/3 22 , dcgshell/4 23 , make//0 24 , help/3 25 , time//1, time//2, time//3 26 , profile_phrase//1 27 , trace//1 28 , catch//3 29 ]). 30 31 32:- module_transparent 33 dcgshell/2, dcgshell/3, dcgshell/4, 34 dcgshell_x/6, shell_prompt/4, make//0. 35 36:- use_module(library(termutils), [get_key/2]).
Pressing Ctrl-D at the prompt or typing 'halt' or 'end_of_file' terminates the shell unifying S2 with the final state. The command 'fail' terminates the shell and causes dcgshell/2 or dcgshell/3 as a whole to fail, without leaving any choice points.
dcgshell/4 allows the specification of an alternate interpreter other than call_dcg/3, which is the default in the other forms.
Special commands
interp(time) will
cause timing information to be printed after each
command is interpreted.69dcgshell(S1,S2) :- dcgshell(call_dcg,dcg,S1,S2). 70dcgshell(Id,S1,S2) :- dcgshell(call_dcg,Id,S1,S2). 71dcgshell(Interp,Id,S1,S2) :- !, 72 shell_prompt(Id,Interp,Goal,Bindings), 73 dcgshell_x(Goal,Bindings,Interp,Id,S1,S2). 74 75 76shell_prompt(Id,Interp,Goal,Bindings) :- 77 context_module(Mod), 78 format(atom(NA),'~p: ~p (~W) >> ',[Mod,Interp,Id,[portray(true),quoted(true),max_depth(3)]]), 79 read_history(h,'!h',[trace,end_of_file],NA, Goal, Bindings). 80 81dcgshell_x(fail,_,_,_,_,_) :- !, fail. 82dcgshell_x(halt,_,_,_,S,S) :- !, nl. 83dcgshell_x(end_of_file,_,_,_,S,S) :- !, nl. 84dcgshell_x(module(Mod),_,Interp,Id,S1,S2) :- !, @(dcgshell(Interp,Id,S1,S2), Mod). 85dcgshell_x(interp(Int2),_,Int1,Id,S1,S2) :- !, 86 format('Changing interpreter from ~w to ~w.\n',[Int1,Int2]), 87 dcgshell(Int2,Id,S1,S2). 88 89dcgshell_x(X^Goal,Bindings,Interp,Id,S1,S2) :- !, 90 X=Id, dcgshell_x(Goal,Bindings,Interp,Id,S1,S2). 91 92dcgshell_x(Goal,Bindings,Interp,Id,S0,S2) :- !, 93 catch( 94 ( current_prolog_flag(prompt_alternatives_on,PromptOn), 95 call(Interp,Goal,S0,S1), 96 include(dcg_shell:bound,Bindings,BoundBindings), 97 ( BoundBindings=[] 98 -> ( PromptOn=determinism 99 -> write('\nok? [.,<return>=yes,;=no] '), 100 dcg_shell:get_key([';','\r','.'],K), (K='\r';K='.'), nl 101 ; true) 102 ; dcg_shell:check_bindings(BoundBindings) 103 ), 104 write(' Yes.\n\n') 105 ; write('\n No.\n'), S0=S1 106 ), 107 Exception, 108 ( Exception=dcg_shell:escape(Ex) -> throw(Ex) 109 ; nl, print_message(error,Exception), S1=S0, nl) 110 ), !, 111 dcgshell(Interp,Id,S1,S2). 112 113bound(_=Value) :- nonvar(Value). 114 115 116 117% useful DCG shell commands
122make --> {make}.
127help(A) --> {help(A)}.136:- meta_predicate time(,,), time(,,,), time(,,,,). 137time(G,A,B) :- time(call_dcg(G,A,B)). 138time(G,A,B,C) :- time(call(G,A,B,C)). 139time(G,A,B,C,D) :- time(call(G,A,B,C,D)).
144:- meta_predicate profile_phrase(,,). 145profile_phrase(G,A,B) :- profile(call_dcg(G,A,B)). 146 147 148:- meta_predicate catch(,,,,). 149catch(Phrase,Ex,Handler,S1,S2) :- 150 catch(call_dcg(Phrase,S1,S2), 151 Ex, call_dcg(Handler,S1,S2)). 152 153:- meta_predicate trace(,,). 154trace(Goal,S1,S2) :- 155 setup_call_cleanup( trace, call_dcg(Goal,S1,S2), notrace). 156 157% ----------------------------- Extract from meta.pl ------------------------
binding ---> (atom=term).
The current Prolog flags are used to determine the print format (see answer_write_options in current_prolog_flag/2).
171check_bindings([]) :- nl. % !! Do we always want this? 172check_bindings([B|BT]) :- 173 current_prolog_flag(answer_write_options,Opts), 174 write_bindings(Opts,[B|BT]), 175 get_key([';','\r','.'],K), (K='\r';K='.'), nl.
The current Prolog flags are used to determine the print format (see answer_write_options in current_prolog_flag/2).
186write_bindings([]) :- !. % !! Do we always want this? 187write_bindings(B) :- 188 current_prolog_flag(answer_write_options,Opts), 189 write_bindings(Opts,B), nl, nl. 190 191write_bindings(Opts,[N=V]) :- 192 ( true % nonvar(V) 193 -> format('\n ~w = ~@ ',[N,write_term(V,Opts)]) 194 ; true 195 ). 196 197write_bindings(Opts,[N=V,X|T]) :- 198 ( true % nonvar(V) 199 -> format('\n ~w = ~@ ',[N,write_term(V,Opts)]) 200 ; true 201 ), 202 write_bindings(Opts,[X|T])