rishi/scryer-prolog
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use ellipses to indicate infinite terms in printer

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This commit is contained in:
Mark Thom
2019-04-25 22:27:23 -06:00
parent 9b93c33491
commit 3783070585
3 changed files with 28 additions and 24 deletions
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2
Cargo.toml
View File

@@ -1,6 +1,6 @@
[package]
name = "scryer-prolog"
version = "0.8.65"
version = "0.8.66"
authors = ["Mark Thom <markjordanthom@gmail.com>"]
repository = "https://github.com/mthom/scryer-prolog"
description = "A modern Prolog implementation written mostly in Rust."

46
src/prolog/heap_print.rs
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@@ -293,6 +293,7 @@ pub struct HCPrinter<'a, Outputter> {
heap_locs: ReverseHeapVarDict,
printed_vars: HashSet<Addr>,
last_item_idx: usize,
cyclic_terms: HashMap<Addr, usize>,
pub(crate) numbervars_offset: BigInt,
pub(crate) numbervars: bool,
pub(crate) quoted: bool,
@@ -407,7 +408,8 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter>
numbervars: false,
numbervars_offset: BigInt::zero(),
quoted: false,
ignore_ops: false }
ignore_ops: false,
cyclic_terms: HashMap::new() }
}
pub fn from_heap_locs(machine_st: &'a MachineState, op_dir: &'a OpDir, output: Outputter,
@@ -601,24 +603,26 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter>
return None;
},
None => if self.machine_st.is_cyclic_term(addr.clone()) {
if self.printed_vars.contains(&addr) {
iter.stack().pop();
match self.cyclic_terms.get(&addr).cloned() {
Some(reps) =>
if reps > 0 {
self.cyclic_terms.insert(addr, reps - 1);
iter.next()
} else {
if !self.at_cdr(", ...") {
push_space_if_amb!(self, "...", {
self.append_str("...");
});
}
if let Some(offset_str) = self.offset_as_string(addr) {
push_space_if_amb!(self, &offset_str, {
self.append_str(&offset_str);
});
iter.stack().pop();
self.cyclic_terms.remove(&addr);
None
},
None => {
self.cyclic_terms.insert(addr, 2);
iter.next()
}
None
} else {
if let Some(s) = self.offset_as_string(addr.clone()) {
let var = Rc::new(s);
self.heap_locs.insert(addr.clone(), var);
}
self.printed_vars.insert(addr);
iter.next()
}
} else {
iter.next()
@@ -720,16 +724,16 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter>
if self.outputter.ends_with(&format!(" {}", op.as_str())) {
result.push(' ');
}
result.push('(');
}
result += &self.print_op_addendum(atom.as_str());
if op.is_some() {
result.push(')');
}
push_space_if_amb!(self, &result, {
self.append_str(&result);
});

4
src/tests.rs
View File

@@ -1526,7 +1526,7 @@ fn test_queries_on_builtins()
assert_prolog_success!(&mut wam, "X = g(X, Y), Y = f(X), copy_term(Y, f(Z)).",
[["Y = f(g(X, Y))", "X = g(X, f(X))", "Z = g(Z, f(Z))"]]);
assert_prolog_success!(&mut wam, "X = g(X, Y), Y = f(X), copy_term(Y, V).",
[["Y = f(g(X, Y))", "X = g(X, f(X))", "V = f(g(_9, V))"]]);
[["V = f(g(g(g(..., V), V), V))", "X = g(X, f(X))", "Y = f(g(X, Y))"]]);
assert_prolog_success!(&mut wam, "f(Y,Y,[X,a,[],Y]) = Term, copy_term(Term, NewTerm).",
[["NewTerm = f(_16, _16, [_19, a, [], _16])",
"Term = f(_0, Y, [_6, a, [], Y])",
@@ -1638,7 +1638,7 @@ fn test_queries_on_builtins()
assert_prolog_failure!(&mut wam, "Pairs = [a-a|Pairs], keysort(Pairs, _).");
assert_prolog_success!(&mut wam, "Pairs = [a-a|Pairs], catch(keysort(Pairs, _), error(E, _), true).",
[["E = type_error(list, [a-a | _25])", "Pairs = [a-a | Pairs]"]]);
[["E = type_error(list, [a-a, a-a, a-a, ...])", "Pairs = [a-a | Pairs]"]]);
assert_prolog_success!(&mut wam, "keysort([], L).",
[["L = []"]]);