Lift the (X11 license) line editor from csharp.exe. it's not readline…

… but it's something. fixes sorear#148

Makefile

@@ -11,7 +11,7 @@ WGET_O=wget --no-check-certificate -O
 cskernel=Kernel.cs Builtins.cs Cursor.cs JSYNC.cs NieczaCLR.cs Utils.cs \
 	 ObjModel.cs BigInteger.cs Printf.cs CodeGen.cs \
 	 GeneratedTrigFunctions.cs Serialize.cs UCD.cs \
-	 SpecialMathFunctions.cs CompilerBinding.cs
+	 SpecialMathFunctions.cs CompilerBinding.cs GetLine.cs
 
 # Tell make to regard the following targets as not being filenames
 .PHONY: all aot test spectest clean realclean

lib/CodeGen.cs

@@ -12,6 +12,7 @@
 using System.IO;
 
 using Niecza;
+using Mono.Terminal;
 
 namespace Niecza.CLRBackend {
     // The portable format is a subset of JSON, and is currently read
@@ -4688,5 +4689,20 @@ public class DowncallReceiver : CallReceiver {
         public static object get_codepoint(object[] args) {
             return Niecza.UCD.DataSet.GetCodepoint((string)args[1]);
         }
+
+        public static object getline_init(object[] args) {
+            return new Handle( new LineEditor( (string)args[1], (int)args[2] ) );
+        }
+
+        public static object getline_edit(object[] args) {
+            var edit = (LineEditor) Handle.Unbox(args[1]);
+            return edit.Edit( (string)args[2], (string)args[3] );
+        }
+
+        public static object getline_close(object[] args) {
+            var edit = (LineEditor) Handle.Unbox(args[1]);
+            edit.SaveHistory();
+            return null;
+        }
     }
 }