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parse negative numbers properly, handle length errors and failures properly.

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This commit is contained in:
Mark Thom
2018-05-12 18:23:57 -06:00
parent 5690409534
commit b0bdf50a78
5 changed files with 51 additions and 21 deletions
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36
src/prolog/lib/builtins.pl
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@@ -3,8 +3,8 @@
:- module(builtins, [(=)/2, (+)/2, (*)/2, (-)/2, (/)/2, (/\)/2,
(\/)/2, (is)/2, (xor)/2, (div)/2, (//)/2, (rdiv)/2, (<<)/2,
(>>)/2, (mod)/2, (rem)/2, (>)/2, (<)/2, (=\=)/2, (=:=)/2,
(-)/1, (>=)/2, (=<)/2, (->)/2, (;)/2, (==)/2, arg/3, catch/3,
throw/1, true/0, false/0]).
(-)/1, (>=)/2, (=<)/2, (->)/2, (;)/2, (==)/2, (\==)/2, arg/3,
catch/3, throw/1, true/0, false/0, length/2]).
% arithmetic operators.
:- op(700, xfx, is).
@@ -40,6 +40,7 @@
% term comparison.
:- op(700, xfx, ==).
:- op(700, xfx, \==).
% unify.
X = X.
@@ -96,3 +97,34 @@ arg(N, Functor, Arg) :- throw(error(type_error(integer, N), arg/3)).
arg_(N, N, N, Functor, Arg) :- !, '$get_arg'(N, Functor, Arg).
arg_(N, N, Arity, Functor, Arg) :- '$get_arg'(N, Functor, Arg).
arg_(N, N0, Arity, Functor, Arg) :- N0 < Arity, N1 is N0 + 1, arg_(N, N1, Arity, Functor, Arg).
% length.
length(Xs, N) :-
var(N), !,
'$skip_max_list'(M, -1, Xs, Xs0),
( Xs0 == [] -> N = M
; var(Xs0) -> '$length_addendum'(Xs0, N, M)).
% ; throw(error(type_error(list, Xs), length/2))).
length(Xs, N) :-
integer(N),
N >= 0, !,
'$skip_max_list'(M, N, Xs, Xs0),
( Xs0 == [] -> N = M
; var(Xs0) -> R is N-M, '$length_rundown'(Xs0, R)).
% ; throw(error(type_error(list, Xs), length/2))).
length(_, N) :-
integer(N), !,
throw(error(domain_error(not_less_than_zero, N), length/2)).
length(_, N) :-
throw(error(type_error(integer, N), length/2)).
'$length_addendum'([], N, N).
'$length_addendum'([_|Xs], N, M) :-
M1 is M + 1,
'$length_addendum'(Xs, N, M1).
'$length_rundown'([], 0) :- !.
'$length_rundown'([_|Xs], N) :-
N1 is N-1,
'$length_rundown'(Xs, N1).

10
src/prolog/lib/lists.pl
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@@ -1,5 +1,7 @@
:- module(lists, [member/2, select/3, append/3, is_list/1, memberchk/2, reverse/2, maplist/2,
maplist/3, maplist/4, maplist/5, maplist/6, maplist/7, maplist/8, maplist/9]).
:- module(lists, [member/2, select/3, append/3, memberchk/2,
reverse/2, maplist/2, maplist/3, maplist/4,
maplist/5, maplist/6, maplist/7, maplist/8,
maplist/9]).
member(X, [X|_]).
member(X, [_|Xs]) :- member(X, Xs).
@@ -10,10 +12,6 @@ select(X, [Y|Xs], [Y|Ys]) :- select(X, Xs, Ys).
append([], R, R).
append([X|L], R, [X|S]) :- append(L, R, S).
is_list(X) :- var(X), !, false.
is_list([]).
is_list([_|T]) :- is_list(T).
memberchk(X, Xs) :- member(X, Xs), !.
reverse(Xs, Ys) :- reverse(Xs, [], Ys).

4
src/prolog/machine/system_calls.rs
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@@ -103,10 +103,10 @@ impl MachineState {
}
pub(super) fn skip_max_list(&mut self) -> Result<(), MachineError> {
let max_steps = self.arith_eval_by_metacall(temp_v!(2))?;
let max_steps = self.store(self.deref(self[temp_v!(2)].clone()));
match max_steps {
Number::Integer(ref max_steps)
Addr::Con(Constant::Number(Number::Integer(ref max_steps)))
if max_steps.to_isize().map(|i| i >= -1).unwrap_or(false) => {
let n = self.store(self.deref(self[temp_v!(1)].clone()));

2
src/prolog/parser

Submodule src/prolog/parser updated: 51e38dd242...7f9094eaed

20
src/tests.rs
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@@ -550,7 +550,7 @@ fn test_queries_on_lists()
assert_prolog_failure!(&mut wam, "?- p([Z, W, Y]).");
assert_prolog_success!(&mut wam, "?- p([Z | W]).", [["Z = _0", "W = [_0]"]]);
assert_prolog_success!(&mut wam, "?- p([Z | [Z]]).", [["Z = _0"]]);
assert_prolog_success!(&mut wam, "?- p([Z | [W]]).", [["Z = _2", "W = _2"]]);
assert_prolog_success!(&mut wam, "?- p([Z | [W]]).", [["Z = _0", "W = _0"]]);
assert_prolog_failure!(&mut wam, "?- p([Z | []]).");
submit(&mut wam, "p([Z]).");
@@ -581,7 +581,7 @@ fn test_queries_on_lists()
assert_prolog_success!(&mut wam, "?- member([X, Y], [a, [b, c], [b, b], [Z, x], [d, f]]).",
[["X = b", "Y = c", "Z = _14"],
["X = b", "Y = b", "Z = _14"],
["X = _14", "Y = x", "Z = _14"],
["X = _2", "Y = x", "Z = _2"],
["X = d", "Y = f", "Z = _14"]]);
assert_prolog_failure!(&mut wam, "?- member([X, Y, Y], [a, [b, c], [b, b], [Z, x], [d, f]]).");
assert_prolog_failure!(&mut wam, "?- member([X, Y, Z], [a, [b, c], [b, b], [Z, x], [d, f]]).");
@@ -640,12 +640,12 @@ fn test_queries_on_conjuctive_queries() {
submit(&mut wam, "q([f(g(x))], Z). q([f(g(y))], Y). q([f(g(z))], a).");
assert_prolog_success!(&mut wam, "?- p(X, Y), q(Y, Z).",
[["Z = _10", "X = a", "Y = [f(g(x))]"],
["Z = _10", "X = a", "Y = [f(g(y))]"],
[["Z = _11", "X = a", "Y = [f(g(x))]"],
["Z = _11", "X = a", "Y = [f(g(y))]"],
["Z = a", "X = a", "Y = [f(g(z))]"]]);
assert_prolog_success!(&mut wam, "?- p(X, Y), !, q(Y, Z).",
[["X = a", "Y = [f(g(x))]", "Z = _10"],
["X = a", "Y = [f(g(y))]", "Z = _10"],
[["X = a", "Y = [f(g(x))]", "Z = _11"],
["X = a", "Y = [f(g(y))]", "Z = _11"],
["X = a", "Y = [f(g(z))]", "Z = a"]]);
assert_prolog_success!(&mut wam, "?- p(X, Y), !, q(Y, X).",
[["X = a", "Y = [f(g(x))]"],
@@ -670,12 +670,12 @@ fn test_queries_on_conjuctive_queries() {
["Y = [f(g(z))]", "X = [f(g(x))]"],
["Y = [f(g(z))]", "X = [f(g(y))]"]]);
assert_prolog_success!(&mut wam, "?- p(X, Y), q(Y, X).",
[["Y = [f(g(x))]", "X = s_0_2"],
["Y = [f(g(y))]", "X = s_0_2"],
[["Y = [f(g(x))]", "X = _10"],
["Y = [f(g(y))]", "X = _10"],
["Y = [f(g(z))]", "X = a"]]);
assert_prolog_success!(&mut wam, "?- q(X, Y), p(Y, X).",
[["Y = s_0_1", "X = [f(g(x))]"],
["Y = s_0_1", "X = [f(g(y))]"],
[["Y = _9", "X = [f(g(x))]"],
["Y = _9", "X = [f(g(y))]"],
["Y = a" , "X = [f(g(z))]"]]);
}