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-rw-r--r--libbuild2/parser.cxx62
1 files changed, 45 insertions, 17 deletions
diff --git a/libbuild2/parser.cxx b/libbuild2/parser.cxx
index 812f201..b118cee 100644
--- a/libbuild2/parser.cxx
+++ b/libbuild2/parser.cxx
@@ -44,7 +44,10 @@ namespace build2
{
o << '=';
names storage;
- to_stream (o, reverse (a.value, storage), quote_mode::normal, '@');
+ to_stream (o,
+ reverse (a.value, storage, true /* reduce */),
+ quote_mode::normal,
+ '@');
}
return o;
@@ -3692,7 +3695,7 @@ namespace build2
if (value v = parse_value_with_attributes (t, tt, pattern_mode::expand))
{
names storage;
- for (name& n: reverse (v, storage))
+ for (name& n: reverse (v, storage, true /* reduce */))
{
// @@ Could this be an out-qualified ad hoc import?
//
@@ -3762,7 +3765,12 @@ namespace build2
fail (l) << "null value in export";
if (val.type != nullptr)
- untypify (val);
+ {
+ // While feels far-fetched, let's preserve empty typed values in the
+ // result.
+ //
+ untypify (val, false /* reduce */);
+ }
export_value = move (val).as<names> ();
@@ -4446,7 +4454,11 @@ namespace build2
if (val && val.type != nullptr)
{
etype = val.type->element_type;
- untypify (val);
+
+ // Note that here we don't want to be reducing empty simple values to
+ // empty lists.
+ //
+ untypify (val, false /* reduce */);
}
if (tt != type::newline)
@@ -4627,7 +4639,7 @@ namespace build2
if (value v = parse_value_with_attributes (t, tt, pattern_mode::expand))
{
names storage;
- cout << reverse (v, storage) << endl;
+ cout << reverse (v, storage, true /* reduce */) << endl;
}
else
cout << "[null]" << endl;
@@ -4660,7 +4672,7 @@ namespace build2
if (value v = parse_value_with_attributes (t, tt, pattern_mode::expand))
{
names storage;
- dr << reverse (v, storage);
+ dr << reverse (v, storage, true /* reduce */);
}
if (tt != type::eos)
@@ -4843,7 +4855,12 @@ namespace build2
// We store prepend/append values untyped (similar to overrides).
//
if (rhs.type != nullptr && kind != type::assign)
- untypify (rhs);
+ {
+ // Our heuristics for prepend/append of a typed value is to preserve
+ // empty (see apply_value_attributes() for details) so do not reduce.
+ //
+ untypify (rhs, false /* reduce */);
+ }
if (p.second)
{
@@ -5152,6 +5169,13 @@ namespace build2
bool rhs_type (false);
if (rhs.type != nullptr)
{
+ // Our heuristics is to not reduce typed RHS empty simple values for
+ // prepend/append and additionally for assign provided LHS is a
+ // container.
+ //
+ bool reduce (kind == type::assign &&
+ (type == nullptr || !type->container));
+
// Only consider RHS type if there is no explicit or variable type.
//
if (type == nullptr)
@@ -5162,7 +5186,7 @@ namespace build2
// Reduce this to the untyped value case for simplicity.
//
- untypify (rhs);
+ untypify (rhs, reduce);
}
if (kind == type::assign)
@@ -6561,14 +6585,13 @@ namespace build2
if (!vnull)
{
if (vtype != nullptr)
- untypify (rhs);
+ untypify (rhs, true /* reduce */);
names& d (rhs.as<names> ());
- // If the value is empty, then untypify() will (typically; no pun
- // intended) represent it as an empty sequence of names rather than
- // a sequence of one empty name. This is usually what we need (see
- // simple_reverse() for details) but not in this case.
+ // If the value is empty, then we asked untypify() to reduce it to
+ // an empty sequence of names rather than a sequence of one empty
+ // name.
//
if (!d.empty ())
{
@@ -7422,7 +7445,8 @@ namespace build2
fail (loc) << "null variable/function name";
names storage;
- vector_view<name_type> ns (reverse (v, storage)); // Movable.
+ vector_view<name_type> ns (
+ reverse (v, storage, true /* reduce */)); // Movable.
size_t n (ns.size ());
// We cannot handle scope-qualification in the eval context as
@@ -7643,7 +7667,7 @@ namespace build2
? value (move (result_data))
: value (*result));
- untypify (val);
+ untypify (val, false /* reduce */);
names& ns (val.as<names> ());
@@ -7754,7 +7778,11 @@ namespace build2
fail (loc) << "no string conversion for " << t;
result_data = move (p.first);
- untypify (result_data); // Convert to untyped simple name.
+
+ // Convert to untyped simple name reducing empty string to empty
+ // names as an optimization.
+ //
+ untypify (result_data, true /* reduce */);
}
if ((concat && vtype != nullptr) || // LHS typed.
@@ -7855,7 +7883,7 @@ namespace build2
// @@ Could move if nv is result_data; see untypify().
//
names nv_storage;
- names_view nv (reverse (*result, nv_storage));
+ names_view nv (reverse (*result, nv_storage, true /* reduce */));
count = splice_names (
loc, nv, move (nv_storage), ns, what, pairn, pp, dp, tp);