Merge pull request #1934 from usethesource/clipboard

added default clipboard utility (ported from Eclipse environment), which should work on any non-headless JVM environment

src/org/rascalmpl/library/util/Clipboard.java

@@ -0,0 +1,39 @@
+package org.rascalmpl.library.util;
+
+import java.awt.datatransfer.DataFlavor;
+import java.awt.datatransfer.StringSelection;
+import java.awt.datatransfer.UnsupportedFlavorException;
+import java.io.IOException;
+import org.rascalmpl.debug.IRascalMonitor;
+import io.usethesource.vallang.IString;
+import io.usethesource.vallang.IValueFactory;
+
+public class Clipboard {
+    private final IValueFactory vf;
+    private final java.awt.datatransfer.Clipboard cp;
+    private IRascalMonitor monitor;
+
+    public Clipboard(IValueFactory vf, IRascalMonitor monitor) {
+        this.vf = vf;
+        this.cp = java.awt.Toolkit.getDefaultToolkit().getSystemClipboard();
+        this.monitor = monitor;
+    }
+
+    public void copy(IString arg) {
+        var selection = new StringSelection(arg.getValue());
+		cp.setContents(selection, selection);
+    }
+
+    public IString paste() {
+        try {
+            if (cp.isDataFlavorAvailable(DataFlavor.stringFlavor)) {
+                return vf.string(cp.getData(DataFlavor.stringFlavor).toString());
+            }
+        }
+        catch (UnsupportedFlavorException | IOException e) {
+           monitor.warning("Clipboard::paste failed", null);
+        }
+
+        return vf.string("");
+    }
+}

src/org/rascalmpl/library/util/Clipboard.rsc

@@ -0,0 +1,39 @@
+@synopsis{Programmatic access to the native system clipboard (copy and paste), with some handy (de)-escaping features.}
+module util::Clipboard
+
+@javaClass{org.rascalmpl.library.util.Clipboard}
+@synopsis{If there is textual content in the current clipboard, then return it as a string.}
+@description{
+This will transfer any plaintext content that is currently on the system clipboard, no matter
+the source to a string value.
+
+If the system's clipboard is not accessible (say we are running in a headless environment),
+then paste always returns the empty string.
+}
+@pitfalls{
+* the first time paste or copy are called the UI toolkit must boot up; it can take a few seconds.
+}
+@benefits{
+* copy/paste allow for interesting and useful user interactions, especially while experimenting on the REPL.
+* paste encodes and escapes all kinds of wild characters automatically.
+}
+java str paste();
+
+@javaClass{org.rascalmpl.library.util.Clipboard}
+@synopsis{Load the contents of a string value into the system clipboard.}
+@description{
+This will put the contents of the string value in into the system clipboard.
+So this is not the string value with quotes and escapes, but the pure string
+data.
+
+If the system's clipboard is not accessible (say we are running in a headless environment),
+then copy always has no effect.
+}
+@pitfalls{
+* the first time paste or copy are called the UI toolkit must boot up; it can take a few seconds.
+}
+@benefits{
+* copy/paste allow for interesting and useful user interactions, especially while experimenting on the REPL. 
+* copy transfers the pure content of the string, no quotes or escapes.
+}
+java void copy(str content);