Merge branch 'python-script-runner'

Author: ctrueden

.gitignore

@@ -1,4 +1,5 @@
 /.classpath
+/.idea/
 /.project
 /.settings/
 /target

README.md

@@ -2,4 +2,21 @@
 
 # Python Scripting
 
-Test repository for a [PyImageJ](https://github.com/imagej/pyimagej) based SciJava scripting language engine.
+This library provides a
+[JSR-223-compliant](https://en.wikipedia.org/wiki/Scripting_for_the_Java_Platform)
+scripting plugin for the [Python](https://python.org/) language, built on
+the [scyjava](https://github.com/scijava/scyjava) Python package.
+
+It is implemented as a `ScriptLanguage` plugin for the [SciJava
+Common](https://github.com/scijava/scijava-common) platform, which means that
+in addition to being usable directly as a `javax.script.ScriptEngineFactory`,
+it also provides some functionality on top, such as the ability to generate
+lines of script code based on SciJava events.
+
+For a complete list of scripting languages available as part of the SciJava
+platform, see the
+[Scripting](https://github.com/scijava/scijava-common/wiki/Scripting) page on
+the SciJava Common wiki.
+
+See also:
+* [Python Scripting](https://imagej.net/scripting/python) on the ImageJ wiki.

repl.sh

@@ -0,0 +1,45 @@
+#!/bin/sh
+set -e
+cd "$(dirname "$0")"
+python -c '
+import os.path
+import xml.etree.ElementTree as ET
+import scyjava
+import subprocess
+from pathlib import Path
+
+def exec(cmd):
+    try:
+        args = cmd.split(" ")
+        subprocess.check_output(cmd.split(" "))
+    except subprocess.CalledProcessError as e:
+        print("== OPERATION FAILED ==")
+        print(e.stdout.decode())
+        print(e.stderr.decode())
+        raise e
+
+pom = ET.parse("pom.xml")
+artifactId = pom.find("{http://maven.apache.org/POM/4.0.0}artifactId").text
+version = pom.find("{http://maven.apache.org/POM/4.0.0}version").text
+jar = Path(f"target/{artifactId}-{version}.jar")
+if not jar.exists():
+    print("Building JAR file...")
+    exec("mvn -Denforcer.skip -Dmaven.test.skip clean package")
+deps_dir = Path("target/dependency")
+if not deps_dir.exists():
+    print("Copying dependencies...")
+    exec("mvn -DincludeScope=runtime dependency:copy-dependencies")
+
+scyjava.config.add_option("-Djava.awt.headless=true")
+scyjava.config.add_classpath(jar.absolute())
+deps = scyjava.config.find_jars(deps_dir.absolute())
+scyjava.config.add_classpath(*deps)
+Context = scyjava.jimport("org.scijava.Context")
+context = Context(False)
+print(f"Context created with {context.getServiceIndex().size()} services.")
+scyjava.enable_python_scripting(context)
+ScriptREPL = scyjava.jimport("org.scijava.script.ScriptREPL")
+repl = ScriptREPL(context, "Python")
+repl.loop()
+context.dispose()
+'

src/main/java/org/scijava/plugins/scripting/python/PythonScriptEngine.java

@@ -34,9 +34,12 @@
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
+import java.util.function.Function;
 
 import javax.script.Bindings;
+import javax.script.ScriptContext;
 import javax.script.ScriptEngine;
 import javax.script.ScriptException;
 
@@ -45,11 +48,10 @@
 import org.scijava.object.ObjectService;
 import org.scijava.plugin.Parameter;
 import org.scijava.script.AbstractScriptEngine;
-import org.scijava.ui.DialogPrompt;
-import org.scijava.ui.UIService;
 
 /**
- * A script engine for Python (PyImageJ).
+ * A script engine for Python (CPython, not Jython!), backed by the
+ * <a href="https://github.com/scijava/scyjava">scyjava</a> library.
  *
  * @author Curtis Rueden
  * @author Karl Duderstadt
@@ -58,29 +60,30 @@
 public class PythonScriptEngine extends AbstractScriptEngine {
 
 	@Parameter
-	ObjectService objectService;
+	private ObjectService objectService;
 
 	@Parameter
-	LogService logService;
+	private LogService logService;
 
-	@Parameter
-	UIService uiService;
-
-	public PythonScriptEngine(Context context) {
+	public PythonScriptEngine(final Context context) {
 		context.inject(this);
 		setLogService(logService);
 		engineScopeBindings = new ScriptBindings();
 	}
 
 	@Override
-	public Object eval(String script) throws ScriptException {
-		if (objectService.getObjects(PythonScriptRunner.class).stream().count() > 0)
-			return objectService.getObjects(PythonScriptRunner.class).get(0).run(script, engineScopeBindings, scriptContext);
-		
-		uiService.showDialog("The PythonScriptRunner could not be found in the ObjectService. To use the\n" +
-			                   "Conda Python 3 script engine Fiji must be launched from python inside a conda\n " +
-			                   "environment and a PythonScriptRunner must be added to the ObjectService.\n", DialogPrompt.MessageType.ERROR_MESSAGE);
-		return null;
+	public Object eval(final String script) throws ScriptException {
+		final Optional<Function> pythonScriptRunner = //
+			objectService.getObjects(Function.class).stream()//
+				.filter(obj -> "PythonScriptRunner".equals(objectService.getName(obj)))//
+				.findFirst();
+		if (!pythonScriptRunner.isPresent()) {
+			throw new IllegalStateException(//
+				"The PythonScriptRunner could not be found in the ObjectService. To use the\n" +
+					"Python script engine, you must call scyjava.enable_scijava_scripting(context)\n" +
+					"with this script engine's associated SciJava context before using it.");
+		}
+		return pythonScriptRunner.get().apply(new Args(script, engineScopeBindings, scriptContext));
 	}
 
 	@Override
@@ -105,10 +108,10 @@ public Bindings createBindings() {
 	}
 
 	//Somehow just type casting did not work...
-	class ScriptBindings implements Bindings {
-		
-		private Map<String, Object> bindingsMap; 
-		
+	private static class ScriptBindings implements Bindings {
+
+		private Map<String, Object> bindingsMap;
+
 		ScriptBindings() {
 			bindingsMap = new HashMap<String, Object>();
 		}
@@ -173,4 +176,16 @@ public Object remove(Object key) {
 			return bindingsMap.remove(key);
 		}
 	}
+
+	private static class Args {
+		public final String script;
+		public final Map<String, Object> vars;
+		public final ScriptContext scriptContext;
+
+		public Args(final String script, final Map<String, Object> vars, final ScriptContext scriptContext) {
+			this.script = script;
+			this.vars = vars;
+			this.scriptContext = scriptContext;
+		}
+	}
 }