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diff --git a/sandbox/sebastien/cpp/apr-2/modules/python/eval.hpp b/sandbox/sebastien/cpp/apr-2/modules/python/eval.hpp
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+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/* $Rev$ $Date$ */
+
+#ifndef tuscany_python_eval_hpp
+#define tuscany_python_eval_hpp
+
+/**
+ * Python script evaluation logic.
+ */
+#include <python2.6/Python.h>
+
+#include "list.hpp"
+#include "value.hpp"
+
+namespace tuscany {
+namespace python {
+
+/**
+ * Represent a Python runtime.
+ */
+class PythonRuntime {
+public:
+    PythonRuntime() {
+        if (Py_IsInitialized())
+            return;
+        Py_InitializeEx(0);
+        const char* arg0 = "";
+        PySys_SetArgv(0, const_cast<char**>(&arg0));
+    }
+};
+
+/**
+ * Return the last python error.
+ */
+const string lastError() {
+    if(PyErr_Occurred()) {
+        PyObject* type;
+        PyObject* val;
+        PyObject* trace;
+        PyErr_Fetch(&type, &val, &trace);
+        if (type != NULL && val != NULL) {
+            PyObject* stype = PyObject_Str(type);    
+            PyObject* sval = PyObject_Str(val);    
+            string msg = string() + PyString_AsString(stype) + " : " + PyString_AsString(sval);
+            Py_DECREF(stype);
+            Py_DECREF(sval);                                    
+            Py_DECREF(type);
+            Py_DECREF(val);
+            Py_XDECREF(trace);
+            PyErr_Print();
+            return msg;
+        }
+        PyErr_Print();
+        Py_XDECREF(type);
+        Py_XDECREF(val);
+        Py_XDECREF(trace);
+        PyErr_Print();
+        return "Unknown Python error";
+    }
+    return "";
+}
+
+/**
+ * Declare conversion functions.
+ */
+PyObject* valueToPyObject(const value& v);
+const value pyObjectToValue(PyObject *o);
+PyObject* valuesToPyTuple(const list<value>& v);
+const list<value> pyTupleToValues(PyObject* o);
+
+/**
+ * Callable python type used to represent a lambda expression.
+ */
+typedef struct {
+  PyObject_HEAD
+  lambda<value(const list<value>&)> func;
+} pyLambda;
+
+PyObject *mkPyLambda(const lambda<value(const list<value>&)>& l);
+
+void pyLambda_dealloc(PyObject* self) {
+    PyMem_DEL(self);
+}
+
+const string pyRepr(PyObject * o) {
+    return PyString_AsString(PyObject_Repr(o));
+}
+
+PyObject* pyLambda_call(PyObject* self, PyObject* args, unused PyObject* kwds) {
+    debug("python::call");
+    const pyLambda* pyl = (pyLambda*)self;
+    const value result = pyl->func(pyTupleToValues(args));
+    debug(result, "python::call::result");
+    Py_DECREF(args);
+    PyObject *pyr = valueToPyObject(result);
+    Py_INCREF(pyr);
+    return pyr;
+}
+
+struct pyProxy {
+    const value name;
+    const lambda<value(const list<value>&)> func;
+
+    pyProxy(const value& name, const lambda<value(const list<value>&)>& func) : name(name), func(func) {
+    }
+
+    const value operator()(const list<value>& args) const {
+        debug(name, "python::proxy::name");
+        const value result = func(cons<value>(name, args));
+        debug(result, "python::proxy::result");
+        return result;
+    }
+};
+
+PyObject* pyLambda_getattr(PyObject *self, PyObject *attrname) {
+    const string name = PyString_AsString(attrname);
+    if (substr(name, 0, 1) == "_")
+        return PyObject_GenericGetAttr(self, attrname);
+
+    if (name == "eval") {
+        Py_INCREF(self);
+        return self;
+    }
+
+    const pyLambda* pyl = (pyLambda*)self;
+    debug(name, "python::getattr::name");
+    PyObject* pyr = mkPyLambda(pyProxy(name, pyl->func));
+    Py_INCREF(pyr);
+    return pyr;
+}
+
+PyTypeObject pyLambda_type = {
+    PyObject_HEAD_INIT(0)
+    0,
+    "lambda",
+    sizeof(pyLambda),
+    0,
+    (destructor)pyLambda_dealloc,
+    0, 0, 0, 0, 0, 0, 0, 0, 0,
+    (ternaryfunc)pyLambda_call,
+    0, 
+    (binaryfunc)pyLambda_getattr,
+    0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0
+};
+
+/**
+ * Create a new python object representing a lambda expression.
+ */
+PyObject *mkPyLambda(const lambda<value(const list<value>&)>& l) {
+    pyLambda* pyl = NULL;
+    pyl = PyObject_NEW(pyLambda, &pyLambda_type);
+    if (pyl != NULL)
+      pyl->func = l;
+    return (PyObject *)pyl;
+}
+
+/**
+ * Convert a list of values to a python list.
+ */
+PyObject* valuesToPyListHelper(PyObject* l, const list<value>& v) {
+    if (isNil(v))
+        return l;
+    PyList_Append(l, valueToPyObject(car(v)));
+    return valuesToPyListHelper(l, cdr(v));
+}
+
+PyObject* valuesToPyTuple(const list<value>& v) {
+    return PyList_AsTuple(valuesToPyListHelper(PyList_New(0), v));
+}
+
+/**
+ * Convert a value to a python object.
+ */
+PyObject* valueToPyObject(const value& v) {
+    switch (type(v)) {
+    case value::List:
+        return valuesToPyTuple(v);
+    case value::Lambda:
+        return mkPyLambda(v);
+    case value::Symbol:
+        return PyString_FromString(c_str(string("'") + v));
+    case value::String:
+        return PyString_FromString(c_str(v));
+    case value::Number:
+        return PyFloat_FromDouble((double)v);
+    case value::Bool:
+        return (bool)v? Py_True : Py_False;
+    default:
+        return Py_None;
+    }
+}
+
+/**
+ * Convert a python tuple to a list of values.
+ */
+
+const list<value> pyTupleToValuesHelper(PyObject* o, const size_t i, const size_t size) {
+    if (i == size)
+        return list<value>();
+    return cons(pyObjectToValue(PyTuple_GetItem(o, i)), pyTupleToValuesHelper(o, i + 1, size));
+}
+
+const list<value> pyTupleToValues(PyObject* o) {
+    return pyTupleToValuesHelper(o, 0, PyTuple_Size(o));
+}
+
+/**
+ * Lambda function used to represent a python callable object.
+ */
+struct pyCallable {
+    PyObject* func;
+
+    pyCallable(PyObject* func) : func(func) {
+        Py_INCREF(func);
+    }
+
+    ~pyCallable() {
+        Py_DECREF(func);
+    }
+
+    const value operator()(const list<value>& args) const {
+        PyObject* pyargs = valuesToPyTuple(args);
+        PyObject* result = PyObject_CallObject(func, pyargs);
+        Py_DECREF(pyargs);
+        const value v = pyObjectToValue(result);
+        Py_DECREF(result);
+        return v;
+    }
+};
+
+/**
+ * Convert a python object to a value.
+ */
+const value pyObjectToValue(PyObject *o) {
+    if (PyString_Check(o)) {
+        const char* s = PyString_AsString(o);
+        if (*s == '\'')
+            return value(s + 1);
+        return value(string(s));
+    }
+    if (PyBool_Check(o))
+        return value(o == Py_True);
+    if (PyInt_Check(o))
+        return value((double)PyInt_AsLong(o));
+    if (PyLong_Check(o))
+        return value((double)PyLong_AsLong(o));
+    if (PyFloat_Check(o))
+        return value((double)PyFloat_AsDouble(o));
+    if (PyTuple_Check(o))
+        return pyTupleToValues(o);
+    if (PyCallable_Check(o))
+        return lambda<value(const list<value>&)>(pyCallable(o));
+    return value();
+}
+
+/**
+ * Convert a python script path to a module name.
+ */
+const string moduleName(const string& path) {
+    return join(".", tokenize("/", substr(path, 0, length(path) -3)));
+}
+
+/**
+ * Evaluate an expression against a script provided as a python object.
+ */
+const failable<value> evalScript(const value& expr, PyObject* script) {
+
+    // Get the requested function
+    PyObject* func = PyObject_GetAttrString(script, c_str(car<value>(expr)));
+    if (func == NULL) {
+
+        // The start, stop, and restart functions are optional
+        const value fn = car<value>(expr);
+        if (fn == "start" || fn == "stop") {
+            PyErr_Clear();
+            return value(lambda<value(const list<value>&)>());
+        }
+
+        return mkfailure<value>(string("Couldn't find function: ") + car<value>(expr) + " : " + lastError());
+    }
+    if (!PyCallable_Check(func)) {
+        Py_DECREF(func);
+        return mkfailure<value>(string("Couldn't find callable function: ") + car<value>(expr));
+    }
+
+    // Convert args to python objects
+    PyObject* args = valuesToPyTuple(cdr<value>(expr));
+
+    // Call the function
+    PyObject* result = PyObject_CallObject(func, args);
+    Py_DECREF(args);
+    Py_DECREF(func);
+    if (result == NULL)
+        return mkfailure<value>(string("Function call failed: ") + car<value>(expr) + " : " + lastError());
+
+    // Convert python result to a value
+    const value v = pyObjectToValue(result);
+    Py_DECREF(result);
+    return v;
+}
+
+/**
+ * Read a python script from an input stream.
+ */
+const failable<PyObject*> readScript(const string& name, const string& path, istream& is) {
+    const list<string> ls = streamList(is);
+    ostringstream os;
+    write(ls, os);
+    PyObject* code = Py_CompileStringFlags(c_str(str(os)), c_str(path), Py_file_input, NULL);
+    if (code == NULL)
+        return mkfailure<PyObject*>(string("Couldn't compile script: ") + path + " : " + lastError());
+    PyObject* mod = PyImport_ExecCodeModuleEx(const_cast<char*>(c_str(name)), code, const_cast<char*>(c_str(path)));
+    if (mod == NULL)
+        return mkfailure<PyObject*>(string("Couldn't import module: ") + path + " : " + lastError());
+    return mod;
+}
+
+/**
+ * Evaluate an expression against a script provided as an input stream.
+ */
+const failable<value> evalScript(const value& expr, istream& is) {
+    failable<PyObject*> script = readScript("script", "script.py", is);
+    if (!hasContent(script))
+        return mkfailure<value>(reason(script));
+    return evalScript(expr, content(script));
+}
+
+}
+}
+#endif /* tuscany_python_eval_hpp */