Merge branch 'improve-error-message'

This commit is contained in:
ToruNiina 2020-02-29 23:43:23 +09:00
commit 9694afbe32
2 changed files with 82 additions and 25 deletions

View File

@ -9,6 +9,81 @@
namespace toml
{
namespace detail
{
// Throw out_of_range from `toml::find` after generating an error message.
//
// The implementation is a bit complicated and there are many edge-cases.
// If you are not interested in the error message generation, just skip this.
template<typename C,
template<typename ...> class M, template<typename ...> class V>
[[noreturn]] void
throw_key_not_found_error(const basic_value<C, M, V>& v, const key& ky)
{
// The top-level table has its region at the first character of the file.
// That means that, in the case when a key is not found in the top-level
// table, the error message points to the first character. If the file has
// its first table at the first line, the error message would be like this.
// ```console
// [error] key "a" not found
// --> example.toml
// |
// 1 | [table]
// | ^------ in this table
// ```
// It actually points to the top-level table at the first character,
// not `[table]`. But it is too confusing. To avoid the confusion, the error
// message should explicitly say "key not found in the top-level table".
const auto& reg = get_region(v);
if(reg.line_num() == "1" && reg.size() == 1)
{
// Here it assumes that top-level table starts at the first character.
// The region corresponds to the top-level table will be generated at
// `parse_toml_file` function.
// It also assumes that the top-level table size is just one and
// the line number is `1`. It is always satisfied. And those conditions
// are satisfied only if the table is the top-level table.
//
// 1. one-character dot-key at the first line
// ```toml
// a.b = "c"
// ```
// toml11 counts whole key as the table key. Here, `a.b` is the region
// of the table "a". It could be counter intuitive, but it works.
// The size of the region is 3, not 1. The above example is the shortest
// dot-key example. The size cannot be 1.
//
// 2. one-character inline-table at the first line
// ```toml
// a = {b = "c"}
// ```
// toml11 consideres the inline table body as the table region. Here,
// `{b = "c"}` is the region of the table "a". The size of the region
// is 9, not 1. The shotest inline table still has two characters, `{`
// and `}`. The size cannot be 1.
//
// 3. one-character table declaration at the first line
// ```toml
// [a]
// ```
// toml11 consideres the whole table key as the table region. Here,
// `[a]` is the table region. The size is 3, not 1.
//
throw std::out_of_range(format_underline(concat_to_string(
"key \"", ky, "\" not found in the top-level table"), {
{std::addressof(reg), "the top-level table starts here"}
}));
}
else
{
// normal table.
throw std::out_of_range(format_underline(concat_to_string(
"key \"", ky, "\" not found"), {
{std::addressof(reg), "in this table"}
}));
}
}
} // detail
// ============================================================================
// exact toml::* type
@ -449,10 +524,7 @@ basic_value<C, M, V> const& find(const basic_value<C, M, V>& v, const key& ky)
const auto& tab = v.as_table();
if(tab.count(ky) == 0)
{
throw std::out_of_range(detail::format_underline(concat_to_string(
"key \"", ky, "\" not found"), {
{std::addressof(detail::get_region(v)), "in this table"}
}));
detail::throw_key_not_found_error(v, ky);
}
return tab.at(ky);
}
@ -463,10 +535,7 @@ basic_value<C, M, V>& find(basic_value<C, M, V>& v, const key& ky)
auto& tab = v.as_table();
if(tab.count(ky) == 0)
{
throw std::out_of_range(detail::format_underline(concat_to_string(
"key \"", ky, "\" not found"), {
{std::addressof(detail::get_region(v)), "in this table"}
}));
detail::throw_key_not_found_error(v, ky);
}
return tab.at(ky);
}
@ -477,10 +546,7 @@ basic_value<C, M, V> find(basic_value<C, M, V>&& v, const key& ky)
typename basic_value<C, M, V>::table_type tab = std::move(v).as_table();
if(tab.count(ky) == 0)
{
throw std::out_of_range(detail::format_underline(concat_to_string(
"key \"", ky, "\" not found"), {
{std::addressof(detail::get_region(v)), "in this table"}
}));
detail::throw_key_not_found_error(v, ky);
}
return basic_value<C, M, V>(std::move(tab.at(ky)));
}
@ -542,10 +608,7 @@ find(const basic_value<C, M, V>& v, const key& ky)
const auto& tab = v.as_table();
if(tab.count(ky) == 0)
{
throw std::out_of_range(detail::format_underline(concat_to_string(
"key \"", ky, "\" not found"), {
{std::addressof(detail::get_region(v)), "in this table"}
}));
detail::throw_key_not_found_error(v, ky);
}
return ::toml::get<T>(tab.at(ky));
}
@ -558,10 +621,7 @@ find(basic_value<C, M, V>& v, const key& ky)
auto& tab = v.as_table();
if(tab.count(ky) == 0)
{
throw std::out_of_range(detail::format_underline(concat_to_string(
"key \"", ky, "\" not found"), {
{std::addressof(detail::get_region(v)), "in this table"}
}));
detail::throw_key_not_found_error(v, ky);
}
return ::toml::get<T>(tab.at(ky));
}
@ -574,10 +634,7 @@ find(basic_value<C, M, V>&& v, const key& ky)
typename basic_value<C, M, V>::table_type tab = std::move(v).as_table();
if(tab.count(ky) == 0)
{
throw std::out_of_range(detail::format_underline(concat_to_string(
"key \"", ky, "\" not found"), {
{std::addressof(detail::get_region(v)), "in this table"}
}));
detail::throw_key_not_found_error(v, ky);
}
return ::toml::get<T>(std::move(tab.at(ky)));
}

View File

@ -55,7 +55,7 @@ struct region_base
// number of characters in the line after the region
virtual std::size_t after() const noexcept {return 0;}
virtual std::vector<std::string> comments()const {return {};}
virtual std::vector<std::string> comments() const {return {};}
// ```toml
// # comment_before
// key = "value" # comment_inline