Implement basic key parsing

This is not complete, but it already does the basics. - Define Key type - Define KeyReader effect for reading Keys - Implement basic KeyReader for terminal escape codes. Not complete - Implement for JLineTerminal - Update Prompt example to use KeyReader
creativescala · Feb 7, 2025 · bb08941 · bb08941
1 parent fc484d6
commit bb08941
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diff --git a/core/jvm/src/main/scala/terminus/JLineTerminal.scala b/core/jvm/src/main/scala/terminus/JLineTerminal.scala
@@ -20,11 +20,12 @@ import org.jline.terminal.Terminal as JTerminal
 import org.jline.terminal.TerminalBuilder
 import org.jline.utils.InfoCmp.Capability
 import terminus.effect.Eof
+import terminus.effect.TerminalKeyReader
 import terminus.effect.Timeout
 
 import scala.concurrent.duration.Duration
 
-class JLineTerminal(terminal: JTerminal) extends Terminal {
+class JLineTerminal(terminal: JTerminal) extends Terminal, TerminalKeyReader {
   private val reader = terminal.reader()
   private val writer = terminal.writer()
 

diff --git a/core/jvm/src/main/scala/terminus/Prompt.scala b/core/jvm/src/main/scala/terminus/Prompt.scala
@@ -16,13 +16,16 @@
 
 package terminus
 
-import terminus.effect.Ascii
 import terminus.effect.Eof
+import terminus.effect.Key
 
+import scala.annotation.tailrec
+
+// The only keys we care about
 enum KeyCode {
-  case Down
-  case Up
   case Enter
+  case Up
+  case Down
 }
 
 // Clear the text we've written
@@ -47,34 +50,17 @@ def write(selected: Int): Program[Unit] = {
   Terminal.flush()
 }
 
+@tailrec
 def read(): Program[KeyCode] = {
-  Terminal.read() match {
+  Terminal.readKey() match {
     case Eof =>
       throw new Exception("Received an EOF")
-    case char: Char =>
-      char match {
-        case Ascii.LF | Ascii.CR => KeyCode.Enter
-        case Ascii.ESC =>
-          Terminal.read() match {
-            // Normal mode
-            case '[' =>
-              Terminal.read() match {
-                case 'A'   => KeyCode.Up
-                case 'B'   => KeyCode.Down
-                case other => read()
-              }
-
-            // Application mode
-            case 'O' =>
-              Terminal.read() match {
-                case 'A'   => KeyCode.Up
-                case 'B'   => KeyCode.Down
-                case other => read()
-              }
-
-            case other => read()
-          }
-        case other => read()
+    case key: Key =>
+      key match {
+        case Key.Enter => KeyCode.Enter
+        case Key.Up    => KeyCode.Up
+        case Key.Down  => KeyCode.Down
+        case other     => read()
       }
   }
 }

diff --git a/core/jvm/src/main/scala/terminus/Terminal.scala b/core/jvm/src/main/scala/terminus/Terminal.scala
@@ -23,6 +23,7 @@ trait Terminal
       effect.Cursor,
       effect.Display[Terminal],
       effect.Erase,
+      effect.KeyReader,
       effect.NonBlockingReader,
       effect.Peeker,
       effect.RawMode[Terminal],
@@ -37,6 +38,7 @@ object Terminal
       Cursor,
       Display,
       Erase,
+      KeyReader,
       NonBlockingReader,
       Peeker,
       RawMode,

diff --git a/core/shared/src/main/scala/terminus/KeyReader.scala b/core/shared/src/main/scala/terminus/KeyReader.scala
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2024 Creative Scala
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+package terminus
+
+import terminus.effect.Eof
+import terminus.effect.Key
+
+trait KeyReader {
+
+  /** Block waiting for a key. */
+  def readKey(): effect.KeyReader ?=> Eof | Key =
+    effect ?=> effect.readKey()
+}
diff --git a/core/shared/src/main/scala/terminus/effect/Key.scala b/core/shared/src/main/scala/terminus/effect/Key.scala
@@ -0,0 +1,173 @@
+/*
+ * Copyright 2024 Creative Scala
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+package terminus.effect
+
+/** Enumeration describing the key presses we recognize from the terminal */
+enum Key {
+
+  /** A standard character, like 'A' or 'z.' */
+  case Character(char: Char)
+  case Space
+  case Escape
+  case ShiftEscape
+  case Return
+  case ControlAt
+  case ControlA
+  case ControlB
+  case ControlC
+  case ControlD
+  case ControlE
+  case ControlF
+  case ControlG
+  case ControlH
+  case ControlI
+  case ControlJ
+  case ControlK
+  case ControlL
+  case ControlM
+  case ControlN
+  case ControlO
+  case ControlP
+  case ControlQ
+  case ControlR
+  case ControlS
+  case ControlT
+  case ControlU
+  case ControlV
+  case ControlW
+  case ControlX
+  case ControlY
+  case ControlZ
+  case Control1
+  case Control2
+  case Control3
+  case Control4
+  case Control5
+  case Control6
+  case Control7
+  case Control8
+  case Control9
+  case Control0
+  case ControlShift1
+  case ControlShift2
+  case ControlShift3
+  case ControlShift4
+  case ControlShift5
+  case ControlShift6
+  case ControlShift7
+  case ControlShift8
+  case ControlShift9
+  case ControlShift0
+  case ControlBackslash
+  case ControlSquareClose
+  case ControlCircumflex
+  case ControlUnderscore
+  case Left
+  case Right
+  case Up
+  case Down
+  case Home
+  case End
+  case Insert
+  case Delete
+  case PageUp
+  case PageDown
+  case ControlLeft
+  case ControlRight
+  case ControlUp
+  case ControlDown
+  case ControlHome
+  case ControlEnd
+  case ControlInsert
+  case ControlDelete
+  case ControlPageUp
+  case ControlPageDown
+  case ShiftLeft
+  case ShiftRight
+  case ShiftUp
+  case ShiftDown
+  case ShiftHome
+  case ShiftEnd
+  case ShiftInsert
+  case ShiftDelete
+  case ShiftPageUp
+  case ShiftPageDown
+  case ControlShiftLeft
+  case ControlShiftRight
+  case ControlShiftUp
+  case ControlShiftDown
+  case ControlShiftHome
+  case ControlShiftEnd
+  case ControlShiftInsert
+  case ControlShiftDelete
+  case ControlShiftPageUp
+  case ControlShiftPageDown
+  case BackTab
+  case Backspace
+  case Enter
+  case Tab
+  case F1
+  case F2
+  case F3
+  case F4
+  case F5
+  case F6
+  case F7
+  case F8
+  case F9
+  case F10
+  case F11
+  case F12
+  case F13
+  case F14
+  case F15
+  case F16
+  case F17
+  case F18
+  case F19
+  case F20
+  case F21
+  case F22
+  case F23
+  case F24
+  case ControlF1
+  case ControlF2
+  case ControlF3
+  case ControlF4
+  case ControlF5
+  case ControlF6
+  case ControlF7
+  case ControlF8
+  case ControlF9
+  case ControlF10
+  case ControlF11
+  case ControlF12
+  case ControlF13
+  case ControlF14
+  case ControlF15
+  case ControlF16
+  case ControlF17
+  case ControlF18
+  case ControlF19
+  case ControlF20
+  case ControlF21
+  case ControlF22
+  case ControlF23
+  case ControlF24
+  case ScrollUp
+  case ScrollDown
+}
diff --git a/core/shared/src/main/scala/terminus/effect/KeyReader.scala b/core/shared/src/main/scala/terminus/effect/KeyReader.scala
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2024 Creative Scala
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+package terminus.effect
+
+trait KeyReader extends Effect {
+  def readKey(): Eof | Key
+}