Add proper 'clear' and 'quit' commands, fixes #49, closes #41

index.html

@@ -28,6 +28,23 @@
         var res = Insect.repl(globalEnv)(line);
         globalEnv = res.newEnv;
 
+        // Handle shell commands
+        if (res.msgType == "command") {
+          if (res.msg == "clear") {
+            // Clear screen:
+            this.clear();
+            return "";
+          } else if (res.msg == "quit") {
+            // Treat as reset:
+            this.clear();
+            globalEnv = Insect.initialEnvironment;
+            return "";
+          } else {
+            return "Unknown command '" + res.msg + "'";
+          }
+
+        }
+
         // Format the output
         var msg = res.msg;
 

index.js

@@ -33,7 +33,9 @@ if (process.argv.length >= 4) {
     usage();
   } else {
     var res = runInsect(arg);
-    console.log(res.msg);
+    if (res.msgType === "value") {
+      console.log(res.msg);
+    }
     process.exit(0);
   }
 }
@@ -60,18 +62,29 @@ if (interactive) {
     var res = runInsect(line);
 
     if (res) {
-      // Format output
-      var msg = res.msg;
-      if (res.msgType === "value" || res.msgType === "value-set") {
-        msg = "\n  " + colored("36", msg);
-      } else if (res.msgType == "error") {
-        msg = "\n  " + colored("31", msg);
-      } else if (res.msgType == "info") {
-        msg = msg.replace(/`([^`\n]+)`/g, '\x1b[36m$1\x1b[0m');
-        msg = msg.replace(/\*([^\*\n]+)\*/g, '\x1b[01m$1\x1b[0m');
+      if (res.msgType == "command") {
+        if (res.msg == "quit") {
+          process.exit(0);
+        } else if (res.msg == "clear") {
+          process.stdout.write('\033[2J\033[0f');
+        } else {
+          console.error("Unknown command '" + res.msg + "'");
+        }
+      }
+      else {
+        // Format output
+        var msg = res.msg;
+        if (res.msgType === "value" || res.msgType === "value-set") {
+          msg = "\n  " + colored("36", msg);
+        } else if (res.msgType == "error") {
+          msg = "\n  " + colored("31", msg);
+        } else if (res.msgType == "info") {
+          msg = msg.replace(/`([^`\n]+)`/g, '\x1b[36m$1\x1b[0m');
+          msg = msg.replace(/\*([^\*\n]+)\*/g, '\x1b[01m$1\x1b[0m');
+        }
+
+        console.log(msg + "\n");
       }
-
-      console.log(msg + "\n");
     }
 
     rl.prompt();
@@ -85,12 +98,15 @@ if (interactive) {
   lineReader.eachLine(process.stdin, function(line) {
     var res = runInsect(line);
     if (res) {
-      // Only output values and halt on errors. Ignore other message types.
+      // Only output values and halt on errors. Ignore 'info' and 'value-set'
+      // message types.
       if (res.msgType === "value") {
         console.log(res.msg);
       } else if (res.msgType == "error") {
         console.error("Error: " + res.msg);
         process.exit(1);
+      } else if (res.msgType == "command" && res.msg == "quit") {
+        process.exit(0);
       }
     }
   });

package.json

@@ -1,6 +1,6 @@
 {
   "name": "insect",
-  "version": "2.1.0",
+  "version": "2.2.0",
   "description": "REPL-style scientific calculator",
   "author": "David Peter <[email protected]>",
   "license": "MIT",

src/Insect.purs

@@ -25,6 +25,7 @@ msgTypeToString Info     = "info"
 msgTypeToString Error    = "error"
 msgTypeToString Value    = "value"
 msgTypeToString ValueSet = "value-set"
+msgTypeToString Cmd      = "command"
 
 -- | Run Insect, REPL-style.
 repl ∷ Environment → String → { msg ∷ String

src/Insect/Interpreter.purs

@@ -33,7 +33,7 @@ data EvalError
 type Expect = Either EvalError
 
 -- | Output types for highlighting.
-data MessageType = Value | ValueSet | Info | Error
+data MessageType = Value | ValueSet | Info | Error | Cmd
 
 -- | The output type of the interpreter.
 data Message = Message MessageType String
@@ -143,4 +143,5 @@ runInsect env (Command List) =
 runInsect env (Command Reset) =
   { msg: Message Info "Environment has been reset"
   , newEnv: initialEnvironment }
-runInsect env (Command _) = { msg: Message Error "???", newEnv: env }
+runInsect env (Command Quit) = { msg: Message Cmd "quit", newEnv: env}
+runInsect env (Command Clear) = { msg: Message Cmd "clear", newEnv: env }

src/Insect/Language.purs

@@ -79,6 +79,7 @@ data Command
  | Reset
  | List
  | Clear
+ | Quit
 
 derive instance eqCommand ∷ Eq Command
 derive instance genericCommand ∷ Generic Command

src/Insect/Parser.purs

@@ -51,7 +51,8 @@ insectLanguage = LanguageDef
   , identLetter: identLetter
   , opStart: oneOf ['+', '-', '*', '·', '×', '/', '÷', '^', '=', '²', '³']
   , opLetter: oneOf ['>', '*']
-  , reservedNames: ["help", "?", "list", "ls", "reset", "clear"]
+  , reservedNames: ["help", "?", "list", "ls", "reset", "clear", "cls", "quit",
+                    "exit"]
   , reservedOpNames: ["->", "+", "-", "*", "×", "/", "÷", "^", "**", "=", "²"]
   , caseSensitive: true
 }
@@ -339,7 +340,8 @@ command =
         (reserved "help" <|> reserved "?") *> pure Help
     <|> (reserved "list" <|> reserved "ls") *> pure List
     <|> (reserved "reset") *> pure Reset
-    <|> (reserved "clear") *> pure Clear
+    <|> (reserved "clear" <|> reserved "cls") *> pure Clear
+    <|> (reserved "quit" <|> reserved "exit") *> pure Quit
   ) <* eof
 
 -- | Parse a variable assignment like `x = 3m*pi`