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Diffstat (limited to 'src/openvic-dataloader/csv/CsvGrammar.hpp')
| -rw-r--r-- | src/openvic-dataloader/csv/CsvGrammar.hpp | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/src/openvic-dataloader/csv/CsvGrammar.hpp b/src/openvic-dataloader/csv/CsvGrammar.hpp new file mode 100644 index 0000000..edce97b --- /dev/null +++ b/src/openvic-dataloader/csv/CsvGrammar.hpp @@ -0,0 +1,129 @@ +#pragma once + +#include <initializer_list> +#include <string> +#include <tuple> +#include <type_traits> +#include <vector> + +#include <openvic-dataloader/csv/LineObject.hpp> + +#include <lexy/callback.hpp> +#include <lexy/dsl.hpp> + +// Grammar Definitions // +namespace ovdl::csv::grammar { + struct StringValue { + static constexpr auto escaped_symbols = lexy::symbol_table<char> // + .map<'"'>('"') + .map<'\''>('\'') + .map<'\\'>('\\') + .map<'/'>('/') + .map<'b'>('\b') + .map<'f'>('\f') + .map<'n'>('\n') + .map<'r'>('\r') + .map<'t'>('\t'); + /// This doesn't actually do anything, so this might to be manually parsed if vic2's CSV parser creates a " from "" + static constexpr auto escaped_quote = lexy::symbol_table<char> // + .map<'"'>('"'); + static constexpr auto rule = [] { + // Arbitrary code points + auto c = -lexy::dsl::lit_c<'"'>; + + auto back_escape = lexy::dsl::backslash_escape // + .symbol<escaped_symbols>(); + + auto quote_escape = lexy::dsl::escape(lexy::dsl::lit_c<'"'>) // + .symbol<escaped_quote>(); + + return lexy::dsl::quoted(c, back_escape, quote_escape); + }(); + + static constexpr auto value = lexy::as_string<std::string>; + }; + + template<auto Sep> + struct PlainValue { + static constexpr auto rule = lexy::dsl::identifier(-(Sep / lexy::dsl::lit_c<'\n'>)); + static constexpr auto value = lexy::as_string<std::string>; + }; + + template<auto Sep> + struct Value { + static constexpr auto rule = lexy::dsl::p<StringValue> | lexy::dsl::p<PlainValue<Sep>>; + static constexpr auto value = lexy::forward<std::string>; + }; + + template<auto Sep> + struct SeperatorCount { + static constexpr auto rule = lexy::dsl::list(Sep); + static constexpr auto value = lexy::count; + }; + + template<auto Sep> + struct LineEnd { + static constexpr auto rule = lexy::dsl::list(lexy::dsl::p<Value<Sep>>, lexy::dsl::trailing_sep(lexy::dsl::p<SeperatorCount<Sep>>)); + static constexpr auto value = lexy::fold_inplace<csv::LineObject>( + std::initializer_list<csv::LineObject::value_type> {}, + [](csv::LineObject& result, auto&& arg) { + if constexpr (std::is_same_v<std::decay_t<decltype(arg)>, std::size_t>) { + // Count seperators, adds to previous value, making it a position + using position_type = csv::LineObject::position_type; + result.emplace_back(static_cast<position_type>(arg + std::get<0>(result.back())), ""); + } else { + if (result.empty()) result.emplace_back(0u, LEXY_MOV(arg)); + else { + auto& [pos, value] = result.back(); + value = arg; + } + } + }); + }; + + template<auto Sep> + struct Line { + + static constexpr auto suffix_setter(csv::LineObject& line) { + auto& [position, value] = line.back(); + if (value.empty()) { + line.set_suffix_end(position); + line.pop_back(); + } else { + line.set_suffix_end(position + 1); + } + }; + + static constexpr auto rule = lexy::dsl::p<LineEnd<Sep>> | lexy::dsl::p<SeperatorCount<Sep>> >> lexy::dsl::p<LineEnd<Sep>>; + static constexpr auto value = + lexy::callback<csv::LineObject>( + [](csv::LineObject&& line) { + suffix_setter(line); + return LEXY_MOV(line); + }, + [](std::size_t prefix_count, csv::LineObject&& line) { + line.set_prefix_end(prefix_count); + // position needs to be adjusted to prefix + for (auto& [position, value] : line) { + position += prefix_count; + } + suffix_setter(line); + return LEXY_MOV(line); + }); + }; + + template<auto Sep> + struct File { + static constexpr auto rule = + lexy::dsl::whitespace(lexy::dsl::newline) + + lexy::dsl::opt(lexy::dsl::list(lexy::dsl::p<Line<Sep>>, lexy::dsl::trailing_sep(lexy::dsl::eol))); + + static constexpr auto value = lexy::as_list<std::vector<csv::LineObject>>; + }; + + using CommaFile = File<lexy::dsl::lit_c<','>>; + using ColonFile = File<lexy::dsl::lit_c<':'>>; + using SemiColonFile = File<lexy::dsl::lit_c<';'>>; + using TabFile = File<lexy::dsl::lit_c<'\t'>>; + using BarFile = File<lexy::dsl::lit_c<'|'>>; +}
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