From a4635fb95235ba4bf077bd59957da0626fc5ba72 Mon Sep 17 00:00:00 2001
From: Benjamin Barenblat <bbarenblat@gmail.com>
Date: Tue, 14 Dec 2021 12:34:06 -0500
Subject: EC, a terminal-based RPN calculator

---
 src/main.cc | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 src/main.cc

(limited to 'src/main.cc')

diff --git a/src/main.cc b/src/main.cc
new file mode 100644
index 0000000..959cda0
--- /dev/null
+++ b/src/main.cc
@@ -0,0 +1,117 @@
+// Copyright 2021 Benjamin Barenblat
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+#include <getopt.h>
+#include <locale.h>
+#include <unistd.h>
+
+#include <fstream>
+#include <iostream>
+#include <stdexcept>
+
+#include "src/ui/stream.h"
+#include "src/ui/terminal.h"
+#include "src/util.h"
+#include "third_party/abseil/absl/strings/string_view.h"
+
+namespace {
+
+constexpr absl::string_view kShortUsage = "Usage: ec [OPTION...] [FILENAME]\n";
+
+constexpr absl::string_view kHelp =
+    R"(
+A Reverse Polish scientific calculator. Invoked directly, ec launches an
+interactive interpreter that displays the stack and accepts input. Invoked on a
+file, ec processes the entire file; if the result stack is nonempty, ec prints
+the stack in space-separated form.
+
+Options:
+      --help                  display this help and exit
+      --version               display version information and exit
+)";
+
+constexpr absl::string_view kAskForHelp =
+    "Try 'ec --help' for more information.\n";
+
+constexpr absl::string_view kVersionInfo = "ec development build\n";
+
+enum {
+  kHelpLongOption = 128,
+  kVersionLongOption = 129,
+};
+
+int TerminalUi() {
+  if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
+    return ec::TerminalUi().Main();
+  } else {
+    return ec::LineUi().Main();
+  }
+}
+
+int ProcessFile(const char* path) {
+  std::ifstream file(path);
+  if (!file.is_open()) {
+    std::cerr << "ec: failed to open file " << path << '\n';
+    return 1;
+  }
+  return ec::StreamUi(file).Main();
+}
+
+}  // namespace
+
+int main(int argc, char* argv[]) {
+  setlocale(LC_ALL, "");
+
+  static option long_options[] = {
+      {"help", no_argument, nullptr, kHelpLongOption},
+      {"version", no_argument, nullptr, kVersionLongOption},
+      {nullptr, 0, nullptr, 0},
+  };
+  while (true) {
+    int c = getopt_long(argc, argv, "", long_options, /*longindex=*/nullptr);
+    if (c == -1) {
+      break;
+    }
+    switch (c) {
+      case kHelpLongOption:
+        std::cout << kShortUsage << kHelp;
+        return 0;
+      case kVersionLongOption:
+        std::cout << kVersionInfo;
+        return 0;
+      case '?':
+        std::cerr << kAskForHelp;
+        return 1;
+      default:
+        std::cerr << "ec: internal error: unhandled getopt switch\nThis is a "
+                     "bug! Please report it.\n";
+        return 1;
+    }
+  }
+
+  try {
+    if (optind == argc) {
+      TerminalUi();
+    } else if (optind == argc - 1) {
+      return ProcessFile(argv[optind]);
+    } else {
+      std::cerr << kShortUsage << kAskForHelp;
+      return 1;
+    }
+  } catch (const std::exception& e) {
+    std::cerr << "ec: internal error: " << DemangleIfPossible(typeid(e).name())
+              << ": " << e.what() << "\nThis is a bug! Please report it.\n";
+    return 1;
+  }
+}
-- 
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