(chore) refactory CLI history

README.md

@@ -25,6 +25,12 @@ The `projects/vs20xx` folders contain Visual Studio projects.
 
 The `projects/xcode` folder contains an Xcode project. 
 
+The `projects/make.mac` folder also contains a `make` project.   
+From that folder, run `make`.
+
+`cd projects/make.mac`   
+`make`
+
 ### Linux
 
 The `projects/make` folder contains a `make` project.   

src/module/repl.wren

@@ -2,15 +2,49 @@ import "meta" for Meta
 import "io" for Stdin, Stdout
 import "os" for Platform
 
+class History {
+  construct new() {
+    _list = []
+    _index = 0
+  }
+  add(line) {
+    if (line=="") return
+    if (line==lastEntry) {
+      _index = _list.count   
+      return
+    }
+
+    _list.add(line)
+    _index = _list.count 
+  }
+  isBottom { _index == _list.count }
+  lastEntry {
+    if (_list.isEmpty) return ""
+
+    return _list[-1]
+  }
+  entry {
+    if (_index == _list.count) return false
+    return _list[_index]
+  }
+  next() {
+    if (_index < _list.count) { _index = _index + 1 }
+    return this
+  }
+  previous() {
+    if (_index > 0) { _index = _index - 1 }
+    return this
+  }
+}
+
 /// Abstract base class for the REPL. Manages the input line and history, but
 /// does not render.
 class Repl {
   construct new() {
     _cursor = 0
     _line = ""
 
-    _history = []
-    _historyIndex = 0
+    _history = History.new()
   }
 
   cursor { _cursor }
@@ -129,35 +163,25 @@ class Repl {
   }
 
   previousHistory() {
-    if (_historyIndex == 0) return
-
-    _historyIndex = _historyIndex - 1
-    _line = _history[_historyIndex]
+    _line = _history.previous().entry || _line
     _cursor = _line.count
   }
 
   nextHistory() {
-    if (_historyIndex >= _history.count) return
-
-    _historyIndex = _historyIndex + 1
-    if (_historyIndex < _history.count) {
-      _line = _history[_historyIndex]
-      _cursor = _line.count
-    } else {
+    _line = _history.next().entry || _line
+    // if we are at the bottom and have not edited the buffer then
+    // allow us to move down into an empty line
+    if (_history.isBottom && _history.lastEntry == _line) {
       _line = ""
-      _cursor = 0
     }
+    _cursor = _line.count
   }
 
   executeInput() {
     // Remove the completion hint.
     refreshLine(false)
 
-    // Add it to the history (if the line is interesting).
-    if (_line != "" && (_history.isEmpty || _history[-1] != _line)) {
-      _history.add(_line)
-      _historyIndex = _history.count
-    }
+    _history.add(_line)
 
     // Reset the current line.
     var input = _line

src/module/repl.wren.inc

@@ -4,15 +4,49 @@ static const char* replModuleSource =
 "import \"io\" for Stdin, Stdout\n"
 "import \"os\" for Platform\n"
 "\n"
+"class History {\n"
+"  construct new() {\n"
+"    _list = []\n"
+"    _index = 0\n"
+"  }\n"
+"  add(line) {\n"
+"    if (line==\"\") return\n"
+"    if (line==lastEntry) {\n"
+"      _index = _list.count   \n"
+"      return\n"
+"    }\n"
+"\n"
+"    _list.add(line)\n"
+"    _index = _list.count \n"
+"  }\n"
+"  isBottom { _index == _list.count }\n"
+"  lastEntry {\n"
+"    if (_list.isEmpty) return \"\"\n"
+"\n"
+"    return _list[-1]\n"
+"  }\n"
+"  entry {\n"
+"    if (_index == _list.count) return false\n"
+"    return _list[_index]\n"
+"  }\n"
+"  next() {\n"
+"    if (_index < _list.count) { _index = _index + 1 }\n"
+"    return this\n"
+"  }\n"
+"  previous() {\n"
+"    if (_index > 0) { _index = _index - 1 }\n"
+"    return this\n"
+"  }\n"
+"}\n"
+"\n"
 "/// Abstract base class for the REPL. Manages the input line and history, but\n"
 "/// does not render.\n"
 "class Repl {\n"
 "  construct new() {\n"
 "    _cursor = 0\n"
 "    _line = \"\"\n"
 "\n"
-"    _history = []\n"
-"    _historyIndex = 0\n"
+"    _history = History.new()\n"
 "  }\n"
 "\n"
 "  cursor { _cursor }\n"
@@ -131,35 +165,25 @@ static const char* replModuleSource =
 "  }\n"
 "\n"
 "  previousHistory() {\n"
-"    if (_historyIndex == 0) return\n"
-"\n"
-"    _historyIndex = _historyIndex - 1\n"
-"    _line = _history[_historyIndex]\n"
+"    _line = _history.previous().entry || _line\n"
 "    _cursor = _line.count\n"
 "  }\n"
 "\n"
 "  nextHistory() {\n"
-"    if (_historyIndex >= _history.count) return\n"
-"\n"
-"    _historyIndex = _historyIndex + 1\n"
-"    if (_historyIndex < _history.count) {\n"
-"      _line = _history[_historyIndex]\n"
-"      _cursor = _line.count\n"
-"    } else {\n"
+"    _line = _history.next().entry || _line\n"
+"    // if we are at the bottom and have not edited the buffer then\n"
+"    // allow us to move down into an empty line\n"
+"    if (_history.isBottom && _history.lastEntry == _line) {\n"
 "      _line = \"\"\n"
-"      _cursor = 0\n"
 "    }\n"
+"    _cursor = _line.count\n"
 "  }\n"
 "\n"
 "  executeInput() {\n"
 "    // Remove the completion hint.\n"
 "    refreshLine(false)\n"
 "\n"
-"    // Add it to the history (if the line is interesting).\n"
-"    if (_line != \"\" && (_history.isEmpty || _history[-1] != _line)) {\n"
-"      _history.add(_line)\n"
-"      _historyIndex = _history.count\n"
-"    }\n"
+"    _history.add(_line)\n"
 "\n"
 "    // Reset the current line.\n"
 "    var input = _line\n"