result: define Bail

src/Manifest.cc

@@ -60,7 +60,7 @@ Edition::tryFromString(std::string str) noexcept {
   } else if (str == "2c") {
     return Ok(Edition(Edition::Cpp26, std::move(str)));
   }
-  return Err(anyhow::anyhow("invalid edition"));
+  Bail("invalid edition");
 }
 
 Result<Package>
@@ -79,7 +79,7 @@ static Result<std::size_t>
 validateOptLevel(const std::size_t optLevel) noexcept {
   if (optLevel > 3) {
     // TODO: use toml::format_error for better diagnostics.
-    return Err(anyhow::anyhow("opt_level must be between 0 and 3"));
+    Bail("opt_level must be between 0 and 3");
   }
   return Ok(optLevel);
 }
@@ -88,18 +88,18 @@ static Result<void>
 validateCxxflag(const std::string_view cxxflag) noexcept {
   // cxxflag must start with `-`
   if (cxxflag.empty() || cxxflag[0] != '-') {
-    return Err(anyhow::anyhow("cxxflag must start with `-`"));
+    Bail("cxxflag must start with `-`");
   }
 
   // cxxflag only contains alphanumeric characters, `-`, `_`, `=`, `+`, `:`,
   // or `.`.
   for (const char c : cxxflag) {
     if (!std::isalnum(c) && c != '-' && c != '_' && c != '=' && c != '+'
         && c != ':' && c != '.') {
-      return Err(anyhow::anyhow(
+      Bail(
           "cxxflag must only contain alphanumeric characters, `-`, `_`, `=`, "
           "`+`, `:`, or `.`"
-      ));
+      );
     }
   }
 
@@ -322,11 +322,11 @@ parseDependencies(const toml::value& val, const char* key) noexcept {
       }
     }
 
-    return Err(anyhow::anyhow(fmt::format(
+    Bail(
         "Only Git dependency, path dependency, and system dependency are "
         "supported for now: {}",
         dep.first
-    )));
+    );
   }
   return Ok(deps);
 }
@@ -428,9 +428,7 @@ findManifest(fs::path candidate) noexcept {
     }
   }
 
-  return Err(
-      anyhow::anyhow("could not find `cabin.toml` here and in its parents")
-  );
+  Bail("could not find `cabin.toml` here and in its parents");
 }
 
 Result<Manifest>

src/Rustify/Result.hpp

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <exception>
+#include <fmt/core.h>
 #include <mitama/anyhow/anyhow.hpp>
 #include <mitama/result/result.hpp>
 #include <mitama/thiserror/thiserror.hpp>
@@ -11,23 +12,25 @@
 namespace anyhow = mitama::anyhow;
 namespace thiserror = mitama::thiserror;
 
-// NOLINTNEXTLINE
+// NOLINTBEGIN(readability-identifier-naming,cppcoreguidelines-macro-usage)
+
 #define Try(...) MITAMA_TRY(__VA_ARGS__)
+#define Bail(...) return Err(Anyhow(__VA_ARGS__))
 
 template <typename T, typename E = void>
 using Result = std::conditional_t<
     std::is_void_v<E>, anyhow::result<T>, mitama::result<T, E>>;
 
 template <typename... Args>
 inline auto
-Ok(Args&&... args)  // NOLINT(readability-identifier-naming)
+Ok(Args&&... args)
     -> decltype(mitama::success(std::forward<Args>(args)...)) {
   return mitama::success(std::forward<Args>(args)...);
 }
 
 template <typename E = void, typename... Args>
 inline auto
-Err(Args&&... args) {  // NOLINT(readability-identifier-naming)
+Err(Args&&... args) {
   if constexpr (std::is_void_v<E>) {
     return mitama::failure(std::forward<Args>(args)...);
   } else {
@@ -38,7 +41,17 @@ Err(Args&&... args) {  // NOLINT(readability-identifier-naming)
 template <thiserror::fixed_string S, typename... T>
 using Error = thiserror::error<S, T...>;
 
-// NOLINTNEXTLINE(readability-identifier-naming)
+template <typename... T>
+inline auto
+Anyhow(fmt::format_string<T...> f, T&&... args) {
+  return anyhow::anyhow(fmt::format(f, std::forward<T>(args)...));
+}
+template <typename T>
+inline auto
+Anyhow(T&& arg) {
+  return anyhow::anyhow(std::forward<T>(arg));
+}
+
 inline constexpr auto to_anyhow = [](std::string e) {
   return anyhow::anyhow(std::move(e));
 };
@@ -48,7 +61,6 @@ inline constexpr auto to_anyhow = [](std::string e) {
 #  include <toml.hpp>
 
 namespace toml {
-// NOLINTBEGIN(readability-identifier-naming)
 
 template <typename T, typename... U>
 inline auto
@@ -61,7 +73,8 @@ try_find(const toml::value& v, const U&... u) noexcept
   }
 }
 
-// NOLINTEND(readability-identifier-naming)
 }  // namespace toml
 
 #endif
+
+// NOLINTEND(readability-identifier-naming,cppcoreguidelines-macro-usage)