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Merged
barcharcraz merged 11 commits into from
Nov 12, 2020
Merged

[feature/format] parse format specs #1378

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9626b9e
add parse_precision.
barcharcraz Oct 1, 2020
6208a74
adopt style review comments.
Oct 12, 2020
23f2cd9
add parse format spec
Oct 12, 2020
ae8cbd9
add tests for parse_format_specs
Oct 12, 2020
131c1f1
actually call the test functions.
Oct 14, 2020
0f5351f
fix tests.
Oct 15, 2020
42bc1d4
test the return value of _Parse_format_specs
Oct 16, 2020
1fccd6e
added more tests for parse_format_specs.
Oct 27, 2020
f92187a
address review comments.
Nov 9, 2020
49c418c
make "we're not done yet" a precondition for _Parse_align.
Nov 12, 2020
2c0f0c4
remove test that voilates new preconditions on _Parse_align.
Nov 12, 2020
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78 changes: 70 additions & 8 deletions stl/inc/format
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Original file line number Diff line number Diff line change
Expand Up @@ -36,11 +36,13 @@ class format_error : public runtime_error {

enum class _Align { _None, _Left, _Right, _Center };

enum class _Sign { _None, _Plus, _Minus, _Space };

struct _Auto_id_tag {};

// clang-format off
template <class _Ty, class _CharT>
concept _Parse_spec_callbacks = requires(_Ty _At, basic_string_view<_CharT> _Sv, _Align _Aln) {
concept _Parse_spec_callbacks = requires(_Ty _At, basic_string_view<_CharT> _Sv, _Align _Aln, _Sign _Sgn) {
{ _At._On_align(_Aln) } -> same_as<void>;
{ _At._On_fill(_Sv) } -> same_as<void>;
{ _At._On_width(_STD declval<int>()) } -> same_as<void>;
Expand All @@ -49,8 +51,10 @@ concept _Parse_spec_callbacks = requires(_Ty _At, basic_string_view<_CharT> _Sv,
{ _At._On_precision(_STD declval<int>()) } -> same_as<void>;
{ _At._On_dynamic_precision(_STD declval<int>()) } -> same_as<void>;
{ _At._On_dynamic_precision(_STD declval<_Auto_id_tag>()) } -> same_as<void>;

/* { _At._On_type(_STD declval<_CharT>()) } -> same_as<void>; */
{ _At._On_sign(_Sgn) } -> same_as<void>;
{ _At._On_hash() } -> same_as<void>;
{ _At._On_zero() } -> same_as<void>;
{ _At._On_type(_STD declval<_CharT>()) } -> same_as<void>;
};
template <class _Ty, class _CharT>
concept _Parse_arg_id_callbacks = requires(_Ty _At) {
Expand Down Expand Up @@ -118,11 +122,7 @@ constexpr const _CharT* _Parse_arg_id(const _CharT* _Begin, const _CharT* _End,

template <class _CharT, _Parse_spec_callbacks<_CharT> _Callbacks_type>
constexpr const _CharT* _Parse_align(const _CharT* _Begin, const _CharT* _End, _Callbacks_type&& _Callbacks) {
// done with parsing, or reached the end of a replacement field.
if (_Begin == _End || *_Begin == '}') {
return _Begin;
}

_STL_INTERNAL_CHECK(_Begin != _End && *_Begin != '}');
// align and fill
auto _Parsed_align = _Align::_None;
auto _Align_pt = _Begin + 1;
Expand Down Expand Up @@ -240,6 +240,68 @@ constexpr const _CharT* _Parse_precision(const _CharT* _Begin, const _CharT* _En
return _Begin;
}

template <class _CharT, _Parse_spec_callbacks<_CharT> _Callbacks_type>
constexpr const _CharT* _Parse_format_specs(const _CharT* _Begin, const _CharT* _End, _Callbacks_type&& _Callbacks) {
if (_Begin == _End || *_Begin == '}') {
return _Begin;
}

_Begin = _Parse_align(_Begin, _End, _Callbacks);
if (_Begin == _End) {
return _Begin;
}

switch (*_Begin) {
case '+':
_Callbacks._On_sign(_Sign::_Plus);
++_Begin;
break;
case '-':
_Callbacks._On_sign(_Sign::_Minus);
++_Begin;
break;
case ' ':
_Callbacks._On_sign(_Sign::_Space);
++_Begin;
break;
default:
break;
}

if (_Begin == _End) {
return _Begin;
}

if (*_Begin == '#') {
_Callbacks._On_hash();
if (++_Begin == _End) {
return _Begin;
}
}

if (*_Begin == '0') {
_Callbacks._On_zero();
if (++_Begin == _End) {
return _Begin;
}
}

_Begin = _Parse_width(_Begin, _End, _Callbacks);
if (_Begin == _End) {
return _Begin;
}

if (*_Begin == '.') {
_Begin = _Parse_precision(_Begin, _End, _Callbacks);
}

// If there's anything remaining we assume it's a type.
if (_Begin != _End && *_Begin != '}') {
_Callbacks._On_type(*_Begin++);
}
return _Begin;
}

template <class _Ty, class _CharT = char>
struct formatter;

Expand Down
85 changes: 78 additions & 7 deletions tests/std/tests/P0645R10_text_formatting_parsing/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
#include <assert.h>
#include <concepts>
#include <format>
#include <optional>
#include <stdio.h>
#include <string_view>

Expand Down Expand Up @@ -32,13 +33,17 @@ struct choose_literal<wchar_t> {
template <typename CharT>
struct testing_callbacks {
_Align expected_alignment = _Align::_None;
_Sign expected_sign = _Sign::_None;
basic_string_view<CharT> expected_fill;
int expected_width = -1;
int expected_dynamic_width = -1;
bool expected_auto_dynamic_width = false;
int expected_precision = -1;
int expected_dynamic_precision = -1;
bool expected_auto_dynamic_precision = false;
bool expected_hash = false;
bool expected_zero = false;
CharT expected_type = '\0';
constexpr void _On_align(_Align aln) {
assert(aln == expected_alignment);
}
Expand All @@ -63,6 +68,18 @@ struct testing_callbacks {
constexpr void _On_dynamic_precision(_Auto_id_tag) {
assert(expected_auto_dynamic_precision);
}
constexpr void _On_sign(_Sign sgn) {
assert(sgn == expected_sign);
}
constexpr void _On_hash() {
assert(expected_hash);
}
constexpr void _On_zero() {
assert(expected_zero);
}
constexpr void _On_type(CharT type) {
assert(type == expected_type);
}
};
template <typename CharT>
testing_callbacks(_Align, basic_string_view<CharT>) -> testing_callbacks<CharT>;
Expand Down Expand Up @@ -93,23 +110,23 @@ constexpr bool test_parse_align() {
auto parse_align_fn = _Parse_align<CharT, testing_callbacks<CharT>>;
using view_typ = basic_string_view<CharT>;

view_typ s0(TYPED_LITERAL(CharT, ""));
view_typ s1(TYPED_LITERAL(CharT, "*<"));
view_typ s2(TYPED_LITERAL(CharT, "*>"));
view_typ s3(TYPED_LITERAL(CharT, "*^"));

test_parse_helper(parse_align_fn, s0, false, view_typ::npos, {_Align::_None, view_typ(TYPED_LITERAL(CharT, ""))});
test_parse_helper(parse_align_fn, s1, false, view_typ::npos, {_Align::_Left, view_typ(TYPED_LITERAL(CharT, "*"))});
test_parse_helper(parse_align_fn, s2, false, view_typ::npos, {_Align::_Right, view_typ(TYPED_LITERAL(CharT, "*"))});
test_parse_helper(
parse_align_fn, s3, false, view_typ::npos, {_Align::_Center, view_typ(TYPED_LITERAL(CharT, "*"))});
test_parse_helper(parse_align_fn, s1, false, view_typ::npos,
{.expected_alignment = _Align::_Left, .expected_fill = view_typ(TYPED_LITERAL(CharT, "*"))});
test_parse_helper(parse_align_fn, s2, false, view_typ::npos,
{.expected_alignment = _Align::_Right, .expected_fill = view_typ(TYPED_LITERAL(CharT, "*"))});
test_parse_helper(parse_align_fn, s3, false, view_typ::npos,
{.expected_alignment = _Align::_Center, .expected_fill = view_typ(TYPED_LITERAL(CharT, "*"))});
if constexpr (same_as<CharT, wchar_t>) {
// This is a CJK character where the least significant byte is the same as ascii '>',
// libfmt and initial drafts of <format> narrowed characters when parsing alignments, causing
// \x343E (which is from CJK unified ideographs extension A) and similar characters to parse as
// an alignment specifier.
auto s4 = L"*\x343E"sv;
test_parse_helper(parse_align_fn, s4, false, view_typ::npos, {_Align::_None, L"*"sv});
test_parse_helper(parse_align_fn, s4, false, view_typ::npos, {.expected_fill = L"*"sv});
}

return true;
Expand Down Expand Up @@ -200,22 +217,76 @@ constexpr bool test_parse_precision() {
return true;
}

template <typename CharT>
constexpr bool test_parse_format_specs() {
auto parse_format_specs_fn = _Parse_format_specs<CharT, testing_callbacks<CharT>>;
using view_typ = basic_string_view<CharT>;

view_typ s0(TYPED_LITERAL(CharT, "6}"));
view_typ s1(TYPED_LITERAL(CharT, "*<6"));
view_typ s2(TYPED_LITERAL(CharT, "*>6}"));
view_typ s3(TYPED_LITERAL(CharT, "*^6}"));
view_typ s4(TYPED_LITERAL(CharT, "6d}"));
view_typ s5(TYPED_LITERAL(CharT, "*^+4.4a}"));
view_typ s6(TYPED_LITERAL(CharT, "*^+#04.4a}"));
test_parse_helper(parse_format_specs_fn, s0, false, s0.size() - 1, {.expected_width = 6});
test_parse_helper(parse_format_specs_fn, s1, false, s1.size(),
{.expected_alignment = _Align::_Left,
.expected_fill = view_typ(TYPED_LITERAL(CharT, "*")),
.expected_width = 6});
test_parse_helper(parse_format_specs_fn, s2, false, s2.size() - 1,
{.expected_alignment = _Align::_Right,
.expected_fill = view_typ(TYPED_LITERAL(CharT, "*")),
.expected_width = 6});
test_parse_helper(parse_format_specs_fn, s3, false, s3.size() - 1,
{.expected_alignment = _Align::_Center,
.expected_fill = view_typ(TYPED_LITERAL(CharT, "*")),
.expected_width = 6});
test_parse_helper(parse_format_specs_fn, s4, false, s4.size() - 1, {.expected_width = 6, .expected_type = 'd'});
test_parse_helper(parse_format_specs_fn, s5, false, s5.size() - 1,
{.expected_alignment = _Align::_Center,
.expected_sign = _Sign::_Plus,
.expected_fill = view_typ(TYPED_LITERAL(CharT, "*")),
.expected_width = 4,
.expected_precision = 4,
.expected_type = 'a'});
test_parse_helper(parse_format_specs_fn, s6, false, s6.size() - 1,
{.expected_alignment = _Align::_Center,
.expected_sign = _Sign::_Plus,
.expected_fill = view_typ(TYPED_LITERAL(CharT, "*")),
.expected_width = 4,
.expected_precision = 4,
.expected_hash = true,
.expected_zero = true,
.expected_type = 'a'});
return true;
}

int main() {
test_parse_align<char>();
test_parse_align<wchar_t>();
static_assert(test_parse_align<char>());
static_assert(test_parse_align<wchar_t>());

test_parse_arg_id<char>();
test_parse_arg_id<wchar_t>();
static_assert(test_parse_arg_id<char>());
static_assert(test_parse_arg_id<wchar_t>());

test_parse_width<char>();
test_parse_width<wchar_t>();
static_assert(test_parse_width<char>());
static_assert(test_parse_width<wchar_t>());

test_parse_precision<char>();
test_parse_precision<wchar_t>();
static_assert(test_parse_precision<char>());
static_assert(test_parse_precision<wchar_t>());

test_parse_format_specs<char>();
test_parse_format_specs<wchar_t>();
static_assert(test_parse_format_specs<char>());
static_assert(test_parse_format_specs<wchar_t>());

return 0;
}