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Clarify role of bindings in script engine.

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This commit is contained in:
James Roseborough
2010-12-04 00:47:30 +00:00
parent 81ad4455dc
commit a07d0f7cb4
2 changed files with 46 additions and 37 deletions
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13
examples/jse/ScriptEngineSample.java
View File

@@ -17,6 +17,11 @@ public class ScriptEngineSample {
ScriptEngineManager sem = new ScriptEngineManager();
ScriptEngine e = sem.getEngineByExtension(".lua");
ScriptEngineFactory f = e.getFactory();
// uncomment to enable the lua-to-java bytecode compiler
// (require bcel library in class path)
// org.luaj.vm2.luajc.LuaJC.install();
System.out.println( "Engine name: " +f.getEngineName() );
System.out.println( "Engine Version: " +f.getEngineVersion() );
System.out.println( "LanguageName: " +f.getLanguageName() );
@@ -51,6 +56,7 @@ public class ScriptEngineSample {
System.out.println("script threw ScriptException as expected, message is '"+se.getMessage()+"'");
}
testEngineBindings(e);
testClientBindings(e);
testUserClasses(e);
@@ -65,7 +71,13 @@ public class ScriptEngineSample {
}
}
public static void testEngineBindings(ScriptEngine e) throws ScriptException {
testBindings(e, e.createBindings());
}
public static void testClientBindings(ScriptEngine e) throws ScriptException {
testBindings(e, new SimpleBindings());
}
public static void testBindings(ScriptEngine e, Bindings b) throws ScriptException {
CompiledScript cs = ((Compilable)e).compile(
"print( 'somejavaint', type(somejavaint), somejavaint )\n" +
"print( 'somejavadouble', type(somejavadouble), somejavadouble )\n" +
@@ -79,7 +91,6 @@ public class ScriptEngineSample {
"someluatable = { 999, 111 }\n" +
"someluafunction = function(x) print( 'hello, world', x ) return 678 end\n" +
"" );
Bindings b = e.createBindings();
b.put("somejavaint", 111);
b.put("somejavadouble", 222.333);
b.put("somejavastring", "abc");

70
src/jse/org/luaj/vm2/script/LuaScriptEngine.java
View File

@@ -157,47 +157,30 @@ public class LuaScriptEngine implements ScriptEngine, Compilable {
public CompiledScript compile(String script) throws ScriptException {
return compile(new StringReader(script));
}
public CompiledScript compile(Reader reader) throws ScriptException {
try {
InputStream ris = new Utf8Encoder(reader);
try {
final LuaFunction f = LoadState.load(ris, "script", null);
if ( f.isclosure() ) {
LuaClosure c = f.checkclosure();
final Prototype p = c.p;
return new CompiledScript() {
public Object eval(ScriptContext context) throws ScriptException {
Bindings b = context.getBindings(ScriptContext.ENGINE_SCOPE);
BindingsEnv env = new BindingsEnv(b);
LuaClosure c = new LuaClosure( p, env.t );
Varargs result = c.invoke(LuaValue.NONE);
env.copyGlobalsToBindings();
return result;
}
public ScriptEngine getEngine() {
return LuaScriptEngine.this;
// most compiled functions are closures with prototypes
final Prototype p = f.checkclosure().p;
return new CompiledScriptImpl() {
protected LuaFunction newFunctionInstance() {
return new LuaClosure( p, null );
}
};
} else {
// when luajc is used, functions are java class instances
final Class c = f.getClass();
return new CompiledScript() {
public Object eval(ScriptContext context) throws ScriptException {
Bindings b = context.getBindings(ScriptContext.ENGINE_SCOPE);
BindingsEnv env = new BindingsEnv(b);
LuaFunction lf;
return new CompiledScriptImpl() {
protected LuaFunction newFunctionInstance() throws ScriptException {
try {
lf = (LuaFunction) c.newInstance();
return (LuaFunction) c.newInstance();
} catch (Exception e) {
throw new ScriptException("instantiation failed: "+e.toString());
}
lf.setfenv(env.t);
Varargs result = lf.invoke(LuaValue.NONE);
env.copyGlobalsToBindings();
return result;
}
public ScriptEngine getEngine() {
return LuaScriptEngine.this;
}
};
}
@@ -211,14 +194,29 @@ public class LuaScriptEngine implements ScriptEngine, Compilable {
}
}
// ------ lua bindings ----- private static final class BindingsBackedEnv extends LuaTable {
public class BindingsEnv {
abstract protected class CompiledScriptImpl extends CompiledScript {
abstract protected LuaFunction newFunctionInstance() throws ScriptException;
public ScriptEngine getEngine() {
return LuaScriptEngine.this;
}
public Object eval(ScriptContext context) throws ScriptException {
Bindings b = context.getBindings(ScriptContext.ENGINE_SCOPE);
LuaFunction f = newFunctionInstance();
ClientBindings cb = new ClientBindings(b);
f.setfenv(cb.env);
Varargs result = f.invoke(LuaValue.NONE);
cb.copyGlobalsToBindings();
return result;
}
}
public class ClientBindings {
public final Bindings b;
public final LuaTable t;
public BindingsEnv( Bindings b ) {
public final LuaTable env;
public ClientBindings( Bindings b ) {
this.b = b;
this.t = new LuaTable();
t.setmetatable(LuaTable.tableOf(new LuaValue[] { LuaValue.INDEX, _G }));
this.env = new LuaTable();
env.setmetatable(LuaTable.tableOf(new LuaValue[] { LuaValue.INDEX, _G }));
this.copyBindingsToGlobals();
}
public void copyBindingsToGlobals() {
@@ -227,7 +225,7 @@ public class LuaScriptEngine implements ScriptEngine, Compilable {
Object val = b.get(key);
LuaValue luakey = toLua(key);
LuaValue luaval = toLua(val);
t.set(luakey, luaval);
env.set(luakey, luaval);
i.remove();
}
}
@@ -237,10 +235,10 @@ public class LuaScriptEngine implements ScriptEngine, Compilable {
CoerceJavaToLua.coerce(javaValue);
}
public void copyGlobalsToBindings() {
LuaValue[] keys = t.keys();
LuaValue[] keys = env.keys();
for ( int i=0; i<keys.length; i++ ) {
LuaValue luakey = keys[i];
LuaValue luaval = t.get(luakey);
LuaValue luaval = env.get(luakey);
String key = luakey.tojstring();
Object val = toJava( luaval );
b.put(key,val);