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Dynamic scripting for the JVM
package org.snapscript.tree.condition;
import java.util.Iterator;
import java.util.concurrent.atomic.AtomicInteger;
import org.snapscript.core.Compilation;
import org.snapscript.core.Context;
import org.snapscript.core.Evaluation;
import org.snapscript.core.Index;
import org.snapscript.core.Local;
import org.snapscript.core.Module;
import org.snapscript.core.Path;
import org.snapscript.core.Result;
import org.snapscript.core.Resume;
import org.snapscript.core.Scope;
import org.snapscript.core.Statement;
import org.snapscript.core.Table;
import org.snapscript.core.Value;
import org.snapscript.core.Yield;
import org.snapscript.core.error.ErrorHandler;
import org.snapscript.core.trace.Trace;
import org.snapscript.core.trace.TraceInterceptor;
import org.snapscript.core.trace.TraceStatement;
import org.snapscript.tree.NameReference;
import org.snapscript.tree.SuspendStatement;
import org.snapscript.tree.collection.Iteration;
import org.snapscript.tree.collection.IterationConverter;
public class ForInStatement implements Compilation {
private final Statement loop;
public ForInStatement(Evaluation identifier, Evaluation collection, Statement body) {
this.loop = new CompileResult(identifier, collection, body);
}
@Override
public Statement compile(Module module, Path path, int line) throws Exception {
Context context = module.getContext();
ErrorHandler handler = context.getHandler();
TraceInterceptor interceptor = context.getInterceptor();
Trace trace = Trace.getNormal(module, path, line);
return new TraceStatement(interceptor, handler, loop, trace);
}
private static class CompileResult extends SuspendStatement {
private final IterationConverter converter;
private final NameReference reference;
private final Evaluation collection;
private final AtomicInteger offset;
private final Statement body;
public CompileResult(Evaluation identifier, Evaluation collection, Statement body) {
this.reference = new NameReference(identifier);
this.converter = new IterationConverter();
this.offset = new AtomicInteger();
this.collection = collection;
this.body = body;
}
@Override
public Result compile(Scope scope) throws Exception {
String name = reference.getName(scope);
Index index = scope.getIndex();
int size = index.size();
int depth = index.index(name);
try {
collection.compile(scope);
offset.set(depth);
return body.compile(scope);
} finally {
index.reset(size);
}
}
@Override
public Result execute(Scope scope) throws Exception {
Value list = collection.evaluate(scope, null);
Object object = list.getValue();
Iteration iteration = converter.convert(scope, object);
Iterable iterable = iteration.getIterable(scope);
Iterator iterator = iterable.iterator();
return resume(scope, iterator);
}
@Override
public Result resume(Scope scope, Iterator iterator) throws Exception {
String name = reference.getName(scope);
Table table = scope.getTable();
Local local = Local.getReference(name, name);
int depth = offset.get();
table.add(depth, local);
while (iterator.hasNext()) {
Object entry = iterator.next();
local.setValue(entry);
Result result = body.execute(scope);
if(result.isYield()) {
return suspend(scope, result, this, iterator);
}
if (result.isReturn()) {
return result;
}
if (result.isBreak()) {
return Result.getNormal();
}
}
return Result.getNormal();
}
@Override
public Resume suspend(Result result, Resume resume, Iterator value) throws Exception {
Yield yield = result.getValue();
Resume child = yield.getResume();
return new ForInResume(child, resume, value);
}
}
}