Files
scryer-prolog/src/prolog/toplevel.pl
2020-04-18 14:16:46 -06:00

340 lines
10 KiB
Prolog

:- module('$toplevel', ['$repl'/1, consult/1, use_module/1, use_module/2]).
:- use_module(library(charsio)).
:- use_module(library(lists)).
:- use_module(library(si)).
'$repl'([_|Args]) :-
maplist('$use_list_of_modules', Args),
false.
'$repl'(_) :- '$repl'.
'$use_list_of_modules'(Mod0) :-
atom_chars(Mod, Mod0),
catch(use_module(Mod), E, '$print_exception'(E)).
'$repl' :-
catch('$read_and_match', E, '$print_exception'(E)),
false. %% this is for GC, until we get actual GC.
'$repl' :-
'$repl'.
'$read_and_match' :-
'$read_query_term'(Term, VarList),
'$instruction_match'(Term, VarList).
% make '$compile_batch', a system routine, callable.
'$$compile_batch' :- '$compile_batch'.
'$instruction_match'(Term, VarList) :-
( var(Term) ->
throw(error(instantiation_error, repl/0))
;
Term = [Item] -> !,
( atom(Item) ->
( Item == user ->
catch('$$compile_batch', E, '$print_exception_with_check'(E))
; consult(Item)
)
;
catch(throw(error(type_error(atom, Item), repl/0)),
E,
'$print_exception_with_check'(E))
)
;
'$submit_query_and_print_results'(Term, VarList)
).
'$submit_query_and_print_results'(Term0, VarList) :-
( expand_goals(Term0, Term) -> true
; Term0 = Term
),
( '$get_b_value'(B), write(' '), call(Term), '$write_eqs_and_read_input'(B, VarList),
!
% clear attribute goal lists, which may be populated by
% copy_term/3 prior to failure.
; '$clear_attribute_goals', write('false.'), nl
).
'$needs_bracketing'(Value, Op) :-
catch((functor(Value, F, _),
current_op(EqPrec, EqSpec, Op),
current_op(FPrec, _, F)),
_,
false),
( EqPrec < FPrec -> true
; '$quoted_token'(F) -> true
; atom_length(F, 1), '$graphic_token_char'(F) -> true
; EqPrec == FPrec,
memberchk(EqSpec, [fx,xfx,yfx])
).
'$write_goal'(G, VarList, MaxDepth) :-
( G = (Var = Value) ->
write(Var),
write(' = '),
( '$needs_bracketing'(Value, (=)) ->
write('('),
write_term(Value, [quoted(true), variable_names(VarList), max_depth(MaxDepth)]),
write(')')
; write_term(Value, [quoted(true), variable_names(VarList), max_depth(MaxDepth)])
)
; G == [] ->
write('true')
; write_term(G, [quoted(true), variable_names(VarList), max_depth(MaxDepth)])
).
'$write_last_goal'(G, VarList, MaxDepth) :-
( G = (Var = Value) ->
write(Var),
write(' = '),
( '$needs_bracketing'(Value, (=)) ->
write('('),
write_term(Value, [quoted(true), variable_names(VarList), max_depth(MaxDepth)]),
write(')')
; write_term(Value, [quoted(true), variable_names(VarList), max_depth(MaxDepth)]),
( '$trailing_period_is_ambiguous'(Value) ->
write(' ')
; true
)
)
; G == [] ->
write('true')
; write_term(G, [quoted(true), variable_names(VarList), max_depth(MaxDepth)])
).
'$write_eq'((G1, G2), VarList, MaxDepth) :-
!,
'$write_goal'(G1, VarList, MaxDepth),
write(', '),
'$write_eq'(G2, VarList, MaxDepth).
'$write_eq'(G, VarList, MaxDepth) :-
'$write_last_goal'(G, VarList, MaxDepth).
'$graphic_token_char'(C) :-
memberchk(C, ['#', '$', '&', '*', '+', '-', '.', ('/'), ':',
'<', '=', '>', '?', '@', '^', '~', ('\\')]).
'$list_last_item'([C], C) :- !.
'$list_last_item'([_|Cs], D) :-
'$list_last_item'(Cs, D).
'$trailing_period_is_ambiguous'(Value) :-
atom(Value),
atom_chars(Value, ValueChars),
'$list_last_item'(ValueChars, Char),
ValueChars \== ['.'],
'$graphic_token_char'(Char).
'$write_eqs_and_read_input'(B, VarList) :-
charsio:extend_var_list(VarList, VarList, NewVarList, fabricated),
sort(NewVarList, SortedVarList),
'$get_b_value'(B0),
'$gather_goals'(SortedVarList, SortedVarList, Goals),
( B0 == B ->
( Goals == [] ->
write('true.'), nl
; thread_goals(Goals, ThreadedGoals, (',')),
'$write_eq'(ThreadedGoals, NewVarList, 20),
write('.'),
nl
)
; thread_goals(Goals, ThreadedGoals, (',')),
'$write_eq'(ThreadedGoals, NewVarList, 20),
'$read_input'(ThreadedGoals, NewVarList)
).
'$read_input'(ThreadedGoals, NewVarList) :-
'$get_single_char'(C),
( C == w ->
nl,
write(' '),
'$write_eq'(ThreadedGoals, NewVarList, 0),
'$read_input'(ThreadedGoals, NewVarList)
; C == p ->
nl,
write(' '),
'$write_eq'(ThreadedGoals, NewVarList, 20),
'$read_input'(ThreadedGoals, NewVarList)
; C == (';') ->
nl, write('; '), false
; C == h ->
'$help_message',
'$read_input'(ThreadedGoals, NewVarList)
; C == '.' ->
nl, write('; ...'), nl
; '$read_input'(ThreadedGoals, NewVarList)
).
'$help_message' :-
nl, nl,
write('SPACE, "n" or ";": next solution, if any\n'),
write('".": stop enumeration\n'),
write('"h": display this help message\n'),
write('"w": write terms without depth limit\n'),
write('"p": print terms with depth limit\n\n').
'$gather_query_vars'([_ = Var | Vars], QueryVars) :-
( var(Var) ->
QueryVars = [Var | QueryVars1],
'$gather_query_vars'(Vars, QueryVars1)
; '$gather_query_vars'(Vars, QueryVars)
).
'$gather_query_vars'([], []).
'$is_a_different_variable'([_ = Binding | Pairs], Value) :-
( Value == Binding, !
; '$is_a_different_variable'(Pairs, Value)
).
'$gather_goals'([], VarList, Goals) :-
'$gather_query_vars'(VarList, QueryVars),
copy_term(QueryVars, QueryVars, Goals).
'$gather_goals'([Var = Value | Pairs], VarList, Goals) :-
( ( nonvar(Value)
; '$is_a_different_variable'(Pairs, Value)
) ->
Goals = [Var = Value | Goals0],
'$gather_goals'(Pairs, VarList, Goals0)
; '$gather_goals'(Pairs, VarList, Goals)
).
'$print_exception'(E) :-
write_term('caught: ', [quoted(false), max_depth(20)]),
writeq(E),
nl.
'$print_exception_with_check'(E) :-
( E = error(_, _:_) -> true % if the error source contains a line
% number, a GNU-style error message
% is expected to be printed instead.
; '$print_exception'(E)
).
'$module_export'(Source, PI) :-
( nonvar(PI) ->
( PI = Name / Arity ->
( var(Name) -> throw(error(instantiation_error, Source))
; integer(Arity) ->
( \+ atom(Name) -> throw(error(type_error(atom, Name), Source))
; Arity < 0 -> throw(error(domain_error(not_less_than_zero, Arity), Source))
; true
)
; throw(error(type_error(integer, Arity), Source))
)
; PI = op(Prec, Spec, Name) ->
( integer(Prec) ->
( \+ atom(Name) ->
throw(error(type_error(atom, Name), Source))
; Prec < 0 ->
throw(error(domain_error(not_less_than_zero, Prec), Source))
; Prec > 1200 ->
throw(error(domain_error(operator_precision, Prec), Source))
; memberchk(Spec, [xfy, yfx, xfx, fx, fy, yf, xf])
; throw(error(domain_error(operator_specification, Spec), Source))
)
; throw(error(type_error(integer, Prec), Source))
)
; throw(error(type_error(module_export, PI), Source))
)
; throw(error(instantiation_error, Source))
).
consult(Item) :-
( atom(Item) -> use_module(Item)
; throw(error(type_error(atom, Item), consult/1))
).
use_module(Module) :-
( nonvar(Module) ->
( Module = library(Filename) -> '$use_module'(Filename)
; atom(Module) -> '$use_module_from_file'(Module)
; throw(error(invalid_module_specifier, use_module/1))
)
; throw(error(instantiation_error, use_module/1))
).
use_module(Module, QualifiedExports) :-
( nonvar(Module) ->
( list_si(QualifiedExports) ->
maplist('$module_export'(use_module/2), QualifiedExports) ->
( Module = library(Filename) ->
'$use_qualified_module'(Filename, QualifiedExports)
; atom(Module) ->
'$use_qualified_module_from_file'(Module, QualifiedExports)
; throw(error(invalid_module_specifier, use_module/2))
)
; throw(error(type_error(list, QualifiedExports), use_module/2))
)
; throw(error(instantiation_error, use_module/2))
).
% expand goals in initialization directives.
user:term_expansion(Term0, (:- initialization(ExpandedGoals))) :-
nonvar(Term0),
Term0 = (:- initialization(Goals)),
expand_goals(Goals, ExpandedGoals),
Goals \== ExpandedGoals.
'$module_expand_goal'(UnexpandedGoals, ExpandedGoals) :-
( '$module_of'(Module, UnexpandedGoals),
'$module_exists'(Module),
Module:goal_expansion(UnexpandedGoals, ExpandedGoals),
UnexpandedGoals \== ExpandedGoals ->
true
; user:goal_expansion(UnexpandedGoals, ExpandedGoals)
).
expand_goals(UnexpandedGoals, ExpandedGoals) :-
nonvar(UnexpandedGoals),
var(ExpandedGoals),
( '$module_expand_goal'(UnexpandedGoals, Goals) ->
true
; Goals = UnexpandedGoals
),
( Goals = (Goal0, Goals0) ->
( expand_goals(Goal0, Goal1) ->
expand_goals(Goals0, Goals1),
thread_goals(Goal1, ExpandedGoals, Goals1, (','))
; expand_goals(Goals0, Goals1),
ExpandedGoals = (Goal0, Goals1)
)
; Goals = (Goals0 -> Goals1) ->
expand_goals(Goals0, ExpandedGoals0),
expand_goals(Goals1, ExpandedGoals1),
ExpandedGoals = (ExpandedGoals0 -> ExpandedGoals1)
; Goals = (Goals0 ; Goals1) ->
expand_goals(Goals0, ExpandedGoals0),
expand_goals(Goals1, ExpandedGoals1),
ExpandedGoals = (ExpandedGoals0 ; ExpandedGoals1)
; Goals = (\+ Goals0) ->
expand_goals(Goals0, Goals1),
ExpandedGoals = (\+ Goals1)
; thread_goals(Goals, ExpandedGoals, (','))
; Goals = ExpandedGoals
).
thread_goals(Goals0, Goals1, Hole, Functor) :-
nonvar(Goals0),
( Goals0 = [G | Gs] ->
( Gs == [] ->
Goals1 =.. [Functor, G, Hole]
; Goals1 =.. [Functor, G, Goals2],
thread_goals(Gs, Goals2, Hole, Functor)
)
; Goals1 =.. [Functor, Goals0, Hole]
).
thread_goals(Goals0, Goals1, Functor) :-
nonvar(Goals0),
( Goals0 = [G | Gs] ->
( Gs = [] ->
Goals1 = G
; Goals1 =.. [Functor, G, Goals2],
thread_goals(Gs, Goals2, Functor)
)
; Goals1 = Goals0
).