cliMain: colorize anyhow error

src/Cabin.cc

@@ -1,13 +1,16 @@
 #include "Cabin.hpp"
 
+#include "Algos.hpp"
 #include "Cli.hpp"
 #include "Cmd.hpp"
 #include "Rustify/Result.hpp"
+#include "TermColor.hpp"
 
 #include <cstdlib>
 #include <exception>
 #include <fmt/core.h>
 #include <span>
+#include <string>
 #include <string_view>
 #include <vector>
 
@@ -62,8 +65,8 @@ getCli() noexcept {
   return cli;
 }
 
-Result<void>
-cliMain(const std::span<char* const> args) noexcept {
+static Result<void>
+parseArgs(const std::span<char* const> args) noexcept {
   // Parse arguments (options should appear before the subcommand, as the help
   // message shows intuitively)
   // cabin --verbose run --release help --color always --verbose
@@ -107,4 +110,21 @@ cliMain(const std::span<char* const> args) noexcept {
   return getCli().printHelp({});
 }
 
+static std::string
+colorizeAnyhowError(std::string s) {
+  // `Caused by:` leaves a trailing newline
+  if (s.find("Caused by:") != std::string::npos) {
+    replaceAll(s, "Caused by:", Yellow("Caused by:").toErrStr());
+    replaceAll(s, "\n", "");
+  }
+  return s;
+}
+
+Result<void, std::string>
+cliMain(const std::span<char* const> args) noexcept {
+  return parseArgs(args).map_err([](const auto& e) {
+    return colorizeAnyhowError(e->what());
+  });
+}
+
 }  // namespace cabin

src/Cabin.hpp

@@ -3,9 +3,10 @@
 #include "Rustify/Result.hpp"
 
 #include <span>
+#include <string>
 
 namespace cabin {
 
-Result<void> cliMain(std::span<char* const> args) noexcept;
+Result<void, std::string> cliMain(std::span<char* const> args) noexcept;
 
 }  // namespace cabin

src/Rustify/Result.hpp

@@ -23,9 +23,11 @@ namespace thiserror = mitama::thiserror;
     }                     \
   } while (false)
 
-template <typename T, typename E = void>
+struct UseAnyhow {};
+
+template <typename T, typename E = UseAnyhow>
 using Result = std::conditional_t<
-    std::is_void_v<E>, anyhow::result<T>, mitama::result<T, E>>;
+    std::is_same_v<E, UseAnyhow>, anyhow::result<T>, mitama::result<T, E>>;
 
 template <typename... Args>
 inline auto

src/main.cc

@@ -6,6 +6,6 @@
 int
 main(int argc, char* argv[]) {
   return cabin::cliMain(std::span<char* const>(argv + 1, argv + argc))
-      .map_err([](const auto& e) { cabin::logger::error("{}", e->what()); })
+      .map_err([](const auto& e) { cabin::logger::error("{}", e); })
       .is_err();
 }