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/ui/terminal.cc | 184 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 184 insertions(+)
 create mode 100644 src/ui/terminal.cc

(limited to 'src/ui/terminal.cc')

diff --git a/src/ui/terminal.cc b/src/ui/terminal.cc
new file mode 100644
index 0000000..ccb9c4d
--- /dev/null
+++ b/src/ui/terminal.cc
@@ -0,0 +1,184 @@
+// 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 "src/ui/terminal.h"
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "src/builtin.h"
+#include "src/error.h"
+#include "src/language.h"
+#include "src/parser_driver.h"
+#include "src/ui/terminal/line.h"
+#include "third_party/abseil/absl/strings/str_cat.h"
+#include "third_party/abseil/absl/strings/str_join.h"
+#include "third_party/abseil/absl/strings/string_view.h"
+
+namespace ec {
+
+int TerminalUi::Main() noexcept {
+  BlockSigwinch();
+  TerminalLine tty;
+
+  State machine_state;
+  std::string input_buffer;
+  while (true) {
+    tty.SetLineImmediately(absl::StrCat(
+        absl::StrJoin(machine_state.stack, " ", FormatStackElement), " > ",
+        input_buffer));
+
+    char c = tty.GetChar();
+    if (c == tty.interrupt_char() || c == tty.quit_char()) {
+      // Somebody hit Ctrl-C or Ctrl-\.
+      return 0;
+    }
+    switch (c) {
+      case kControlD:
+        if (input_buffer.empty()) {
+          return 0;
+        }
+        tty.Beep();
+        break;
+
+      case kControlU:
+        input_buffer.clear();
+        break;
+
+      case '\n':
+      case '\r':
+      case ' ':
+        try {
+          std::vector<std::shared_ptr<const Term>> program;
+          if (input_buffer.empty()) {
+            program = {std::make_shared<ForeignProgramTerm>(BuiltinDup)};
+          } else {
+            program = ParseFromString(input_buffer);
+          }
+
+          State s = machine_state;
+          EvaluateAll(program, s);
+          machine_state = s;
+          input_buffer.clear();
+        } catch (const Error& e) {
+          tty.Beep();
+        }
+        break;
+
+      case '\x7f':
+        try {
+          if (input_buffer.empty()) {
+            State s = machine_state;
+            ForeignProgramTerm(BuiltinDrop).Evaluate(s);
+            machine_state = s;
+          } else {
+            input_buffer.pop_back();
+          }
+        } catch (const Error& e) {
+          tty.Beep();
+        }
+        break;
+
+      case '+':
+      case '-':
+      case '*':
+      case '/':
+        try {
+          std::vector<std::shared_ptr<const Term>> program =
+              ParseFromString(absl::StrCat(input_buffer, std::string(1, c)));
+          State s = machine_state;
+          EvaluateAll(program, s);
+          machine_state = s;
+          input_buffer.clear();
+        } catch (const Error& e) {
+          tty.Beep();
+        }
+        break;
+
+      case '.':
+      case '0':
+      case '1':
+      case '2':
+      case '3':
+      case '4':
+      case '5':
+      case '6':
+      case '7':
+      case '8':
+      case '9':
+      case 'A':
+      case 'B':
+      case 'C':
+      case 'D':
+      case 'E':
+      case 'F':
+      case 'G':
+      case 'H':
+      case 'I':
+      case 'J':
+      case 'K':
+      case 'L':
+      case 'M':
+      case 'N':
+      case 'O':
+      case 'P':
+      case 'Q':
+      case 'R':
+      case 'S':
+      case 'T':
+      case 'U':
+      case 'V':
+      case 'W':
+      case 'X':
+      case 'Y':
+      case 'Z':
+      case '_':
+      case 'a':
+      case 'b':
+      case 'c':
+      case 'd':
+      case 'e':
+      case 'f':
+      case 'g':
+      case 'h':
+      case 'i':
+      case 'j':
+      case 'k':
+      case 'l':
+      case 'm':
+      case 'n':
+      case 'o':
+      case 'p':
+      case 'q':
+      case 'r':
+      case 's':
+      case 't':
+      case 'u':
+      case 'v':
+      case 'w':
+      case 'x':
+      case 'y':
+      case 'z':
+        input_buffer.push_back(c);
+        break;
+
+      default:
+        tty.Beep();
+        break;
+    }
+  }
+}
+
+}  // namespace ec
-- 
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