Raito Bezarius
135c28be53
Parsing and completing enumerations on the CLI was usually done by hand. With this enum trait, the parsing and completion is automated away. Change-Id: Icd49729564355d4c79e2c8050ce7e8b9d8e7eda3 Signed-off-by: Raito Bezarius <raito@lix.systems>
77 lines
1.9 KiB
C++
77 lines
1.9 KiB
C++
#pragma once
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///@file
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#include <string_view>
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#include <type_traits>
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#include <utility>
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#include <optional>
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#include <ranges>
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#include "lix/libutil/args.hh"
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namespace nix::cli {
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template<typename Enum>
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struct enum_cli_traits;
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template<typename Enum>
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constexpr std::string_view toString(Enum value)
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{
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for (const auto & [name, val] : enum_cli_traits<Enum>::values) {
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if (val == value) {
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return name;
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}
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}
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std::terminate();
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}
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template<typename Enum>
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std::optional<Enum> fromString(std::string_view str)
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{
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for (const auto & [name, val] : enum_cli_traits<Enum>::values) {
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if (name == str) {
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return val;
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}
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}
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return std::nullopt;
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}
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template<typename Enum>
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void completeAmongEnumChoices(AddCompletions & completions, size_t, std::string_view prefix)
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{
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for (const auto & [name, _] : enum_cli_traits<Enum>::values) {
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if (name.starts_with(prefix)) {
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completions.add(name);
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}
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}
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}
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template<typename Enum>
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Enum parseEnumArg(std::string text)
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{
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auto valueOpt = fromString<Enum>(text);
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if (valueOpt) {
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return *valueOpt;
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} else {
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auto names = std::ranges::views::keys(enum_cli_traits<Enum>::values)
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| std::ranges::to<std::set<std::string>>();
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auto suggestions = Suggestions::bestMatches(names, text);
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throw UsageError(suggestions, "'%s' is not a recognised '%s'", text, enum_cli_traits<Enum>::typeName);
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}
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}
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template<typename Enum>
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std::optional<Enum> parseOptionalEnumArg(std::string text)
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{
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auto target = fromString<Enum>(text);
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if (!target && text != "") {
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auto names = std::ranges::views::keys(enum_cli_traits<Enum>::values) | std::ranges::to<std::set>();
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auto suggestions = Suggestions::bestMatches(names, text);
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throw UsageError(suggestions, "'%s' is not a recognised '%s'", text, enum_cli_traits<Enum>::typeName);
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}
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return target;
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}
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}
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