Utility functions and headers used by the sample store app, function objects, lists and strawman pointer utils. Started to implement a generic value holder object that can help exchange data with scripting components.

git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@814481 13f79535-47bb-0310-9956-ffa450edef68

4 files changed, 1193 insertions, 0 deletions

diff --git a/cpp/sca/runtime/core/src/tuscany/function.hpp b/cpp/sca/runtime/core/src/tuscany/function.hpp
new file mode 100644
index 0000000000..e0e8889dad
--- /dev/null
+++ b/cpp/sca/runtime/core/src/tuscany/function.hpp
@@ -0,0 +1,235 @@
+/*
+ * 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_function_hpp
+#define tuscany_function_hpp
+
+/**
+ * Lambda function type, used to represent service operations.
+ */
+
+#include <iostream>
+#include "gc.hpp"
+
+using std::ostream;
+
+namespace tuscany {
+
+/**
+ * Debug counters.
+ */
+long int countProxies;
+long int countFProxies = 0;
+long int countCProxies = 0;
+long int countLambdas = 0;
+long int countELambdas = 0;
+long int countCLambdas = 0;
+long int countFLambdas = 0;
+
+bool resetLambdaCounters() {
+    countLambdas = countELambdas = countCLambdas = countFLambdas = countProxies = countFProxies = countCProxies = 0;
+    return true;
+}
+
+bool printLambdaCounters() {
+    using std::cout;
+    using std::endl;
+    cout << "countLambdas " << countLambdas << endl;
+    cout << "countELambdas " << countELambdas << endl;
+    cout << "countFLambdas " << countFLambdas << endl;
+    cout << "countCLambdas " << countCLambdas << endl;
+    cout << "countProxies " << countProxies << endl;
+    cout << "countFProxies " << countFProxies << endl;
+    cout << "countCProxies " << countCProxies << endl;
+    return true;
+}
+
+/**
+ * Lambda function type.
+ */
+
+template<typename R, typename... P> class Callable {
+public:
+    unsigned int refCount;
+
+    Callable() : refCount(0) {
+    }
+
+    virtual const int size() const = 0;
+
+    virtual const R operator()(P... p) const = 0;
+
+    virtual ~Callable() {
+    }
+
+    unsigned int acquire() {
+        return ++refCount;
+    }
+
+    unsigned int release() {
+        return --refCount;
+    }
+
+    template<typename F> class Proxy: public Callable {
+    public:
+        explicit Proxy(const F& f) : function(f) {
+            countProxies++;
+            countFProxies ++;
+        }
+
+        Proxy(const Proxy& p) : function(p.function) {
+            countProxies++;
+            countCProxies ++;
+        }
+
+        ~Proxy() {
+            countProxies--;
+        }
+
+        virtual const R operator() (P... p) const {
+            return function(std::forward<P>(p)...);
+        }
+
+        virtual const int size() const {
+            return sizeof(function);
+        }
+
+    private:
+        const F function;
+    };
+
+};
+
+template<typename S> class lambda;
+
+template<typename R, typename... P> class lambda<R(P...)> {
+public:
+    lambda() : callable(0) {
+        countLambdas++;
+        countELambdas++;
+    }
+
+    template<typename F> explicit lambda(const F f) : callable(0) {
+        typedef typename CallableType::template Proxy<F> ProxyType;
+
+        countLambdas++;
+        countFLambdas++;
+        callable = gc_counting_ptr<CallableType>(new ProxyType(f));
+    }
+
+    lambda(const lambda& l) {
+        countLambdas++;
+        countCLambdas++;
+        callable = l.callable;
+    }
+
+    const lambda& operator=(const lambda& l) {
+        if (this == &l)
+        return *this;
+        callable = l.callable;
+        return *this;
+    }
+
+    ~lambda() {
+        countLambdas--;
+    }
+
+    const bool operator==(const lambda& l) const {
+        if (this == &l)
+        return true;
+        return callable == l.callable;
+    }
+
+    const bool operator!=(const lambda& l) const {
+        return !this->operator==(l);
+    }
+
+    const R operator()(P... p) const {
+        return (*callable)(std::forward<P>(p)...);
+    }
+
+    template<typename S> friend ostream& operator<<(ostream&, const lambda<S>&);
+
+private:
+    typedef Callable<R,P...> CallableType;
+    gc_counting_ptr<CallableType> callable;
+};
+
+template<typename S> ostream& operator<<(ostream& out, const lambda<S>& l) {
+    return out << "lambda::" << l.callable;
+}
+
+/**
+ * Creates a lambda function from a pointer to a function.
+ */
+template<typename R, typename... P> lambda<R(P...)> makeLambda(const R (* const f)(P...)) {
+    return lambda<R(P...)>(f);
+}
+
+/**
+ * Curry a lambda function.
+ */
+template<typename R, typename T, typename... P> class Curried {
+private:
+    const T v;
+    const lambda<R(T, P...)>f;
+
+public:
+    Curried(const lambda<R(T, P...)>& f, const T& v): v(v), f(f) {
+    }
+
+    const R operator()(P... p) const {
+        return f(v, std::forward<P>(p)...);
+    }
+
+};
+
+template<typename R, typename T, typename... P> const lambda<R(P...)> curry(const lambda<R(T, P...)>& f, const T& t) {
+    return (lambda<R(P...)>)Curried<R, T, P...>(f, t);
+}
+
+template<typename R, typename T, typename U, typename... P> const lambda<R(P...)> curry(const lambda<R(T, U, P...)>& f, const T& t, const U& u) {
+    return curry(curry(f, t), u);
+}
+
+template<typename R, typename T, typename U, typename V, typename... P> const lambda<R(P...)> curry(const lambda<R(T, U, P...)>& f, const T& t, const U& u, const V& v) {
+    return curry(curry(curry(f, t), u), v);
+}
+
+/**
+ * A lambda function that returns the given value.
+ */
+template<typename T> struct unitReturn {
+    const T v;
+    unitReturn(const T& v) :
+        v(v) {
+    }
+    const T operator()() const {
+        return v;
+    }
+};
+
+template<typename T> const lambda<T()> unit(const T& v) {
+    return lambda<T()> (unitReturn<T> (v));
+}
+
+}
+#endif /* tuscany_function_hpp */
diff --git a/cpp/sca/runtime/core/src/tuscany/gc.hpp b/cpp/sca/runtime/core/src/tuscany/gc.hpp
new file mode 100644
index 0000000000..803ec31643
--- /dev/null
+++ b/cpp/sca/runtime/core/src/tuscany/gc.hpp
@@ -0,0 +1,269 @@
+/*
+ * 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_gc_hpp
+#define tuscany_gc_hpp
+
+/**
+ * Garbage collected pointer.
+ */
+
+#include <ostream>
+
+using std::ostream;
+
+namespace tuscany
+{
+
+template<typename T> class gc_ptr {
+public:
+    explicit gc_ptr(T* p = 0) throw() : countingRef(p == 0? 0 : new CountingRef(p)) {
+    }
+
+    ~gc_ptr() throw() {
+        release();
+    }
+
+    gc_ptr(const gc_ptr& r) throw() : countingRef(r.countingRef) {
+        acquire(r.countingRef);
+    }
+
+    gc_ptr& operator=(const gc_ptr& r) throw() {
+        if(this == &r)
+            return *this;
+        acquire(r.countingRef);
+        release();
+        countingRef = r.countingRef;
+        return *this;
+    }
+
+    const bool operator==(const gc_ptr& r) const throw() {
+        if (this == &r)
+            return true;
+        if (countingRef == NULL)
+            return r.countingRef == NULL;
+        if (r.countingRef == NULL)
+            return false;
+        return countingRef-> ptr == r.countingRef->ptr;
+    }
+
+    const bool operator!=(const gc_ptr& r) const throw() {
+        return !this->operator ==(r);
+    }
+
+    T& operator*() const throw() {
+        return *countingRef->ptr;
+    }
+
+    T* operator->() const throw() {
+        return countingRef->ptr;
+    }
+
+    operator T*() const throw() {
+        return countingRef->ptr;
+    }
+
+    template<typename X> friend ostream& operator<<(ostream&, const gc_ptr<X>&);
+
+private:
+    struct CountingRef {
+        T* ptr;
+        unsigned count;
+
+        CountingRef(T* p) throw() :
+            ptr(p), count(1) {
+        }
+    }* countingRef;
+
+    void acquire(CountingRef* ref) throw() {
+        if(ref)
+            ++ref->count;
+    }
+
+    void release() throw() {
+        if(countingRef) {
+            if(--countingRef->count == 0) {
+                delete countingRef->ptr;
+                delete countingRef;
+            }
+        }
+    }
+};
+
+template<typename T> ostream& operator<<(ostream& out, const gc_ptr<T>& p) {
+    return out << p.countingRef->ptr;
+}
+
+/**
+ * Garbage collected pointer to an array.
+ */
+template<typename T> class gc_aptr {
+public:
+    explicit gc_aptr(T* p = 0) throw() : countingRef(p == 0? 0 : new CountingRef(p)) {
+    }
+
+    ~gc_aptr() throw() {
+        release();
+    }
+
+    gc_aptr(const gc_aptr& r) throw() : countingRef(r.countingRef) {
+        acquire(r.countingRef);
+    }
+
+    gc_aptr& operator=(const gc_aptr& r) throw() {
+        if(this == &r)
+            return *this;
+        acquire(r.countingRef);
+        release();
+        countingRef = r.countingRef;
+        return *this;
+    }
+
+    const bool operator==(const gc_aptr& r) const throw() {
+        if (this == &r)
+            return true;
+        if (countingRef == NULL)
+            return r.countingRef == NULL;
+        if (r.countingRef == NULL)
+            return false;
+        return countingRef-> ptr == r.countingRef->ptr;
+    }
+
+    const bool operator!=(const gc_aptr& r) const throw() {
+        return !this->operator ==(r);
+    }
+
+    T& operator*() const throw() {
+        return *countingRef->ptr;
+    }
+
+    T* operator->() const throw() {
+        return countingRef->ptr;
+    }
+
+    operator T*() const throw() {
+        return countingRef->ptr;
+    }
+
+    template<typename X> friend ostream& operator<<(ostream&, const gc_aptr<X>&);
+
+private:
+    struct CountingRef {
+        T* ptr;
+        unsigned count;
+
+        CountingRef(T* p) throw() :
+            ptr(p), count(1) {
+        }
+    }* countingRef;
+
+    void acquire(CountingRef* ref) throw() {
+        if(ref)
+            ++ref->count;
+    }
+
+    void release() throw() {
+        if(countingRef) {
+            if(--countingRef->count == 0) {
+                delete[] countingRef->ptr;
+                delete countingRef;
+            }
+        }
+    }
+};
+
+template<typename T> ostream& operator<<(ostream& out, const gc_aptr<T>& p) {
+    return out << p.countingRef->ptr;
+}
+
+/**
+ * Garbage collected pointer to a reference counting object.
+ */
+template<typename T> class gc_counting_ptr {
+public:
+    explicit gc_counting_ptr(T* p = 0) throw() : ptr(p) {
+        acquire(p);
+    }
+
+    ~gc_counting_ptr() throw() {
+        release();
+    }
+
+    gc_counting_ptr(const gc_counting_ptr& r) throw() : ptr(r.ptr) {
+        acquire(ptr);
+    }
+
+    gc_counting_ptr& operator=(const gc_counting_ptr& r) throw() {
+        if(this == &r)
+            return *this;
+        acquire(r.ptr);
+        release();
+        ptr = r.ptr;
+        return *this;
+    }
+
+    const bool operator==(const gc_counting_ptr& r) const throw() {
+        if (this == &r)
+            return true;
+        return ptr == r.ptr;
+    }
+
+    const bool operator!=(const gc_counting_ptr& r) const throw() {
+        return !this->operator ==(r);
+    }
+
+    T& operator*() const throw() {
+        return *ptr;
+    }
+
+    T* operator->() const throw() {
+        return ptr;
+    }
+
+    operator T*() const throw() {
+        return ptr;
+    }
+
+    template<typename X> friend ostream& operator<<(ostream&, const gc_counting_ptr<X>&);
+
+private:
+    T* ptr;
+
+    void acquire(T* p) throw() {
+        if(p)
+            p->acquire();
+    }
+
+    void release() throw() {
+        if(ptr) {
+            if(ptr->release() == 0) {
+                delete ptr;
+            }
+        }
+    }
+};
+
+template<typename T> ostream& operator<<(ostream& out, const gc_counting_ptr<T>& p) {
+    return out << p.ptr;
+}
+
+}
+#endif /* tuscany_gc_hpp */
diff --git a/cpp/sca/runtime/core/src/tuscany/list.hpp b/cpp/sca/runtime/core/src/tuscany/list.hpp
new file mode 100644
index 0000000000..e180ad6134
--- /dev/null
+++ b/cpp/sca/runtime/core/src/tuscany/list.hpp
@@ -0,0 +1,348 @@
+/*
+ * 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_list_hpp
+#define tuscany_list_hpp
+
+/**
+ * Simple list functions.
+ */
+
+#include <iostream>
+#include "function.hpp"
+
+using std::ostream;
+
+namespace tuscany {
+
+long countlists = 0;
+long countIlists = 0;
+long countClists = 0;
+long countElists = 0;
+
+bool resetlistCounters() {
+    countlists = countIlists = countClists = countElists = 0;
+    return true;
+}
+
+bool printlistCounters() {
+    using std::cout;
+    using std::endl;
+    cout << "countlists " << countlists << endl;
+    cout << "countElists " << countElists << endl;
+    cout << "countIlists " << countIlists << endl;
+    cout << "countClists " << countClists << endl;
+    return true;
+}
+
+/**
+ * A car/cdr lisp-like pair, base structure to construct lists.
+ */
+
+template<typename T> struct list {
+    bool nil;
+    T car;
+    lambda<list<T> ()> cdr;
+
+    list(const T car, const lambda<list<T> ()> cdr) :
+        nil(false), car(car), cdr(cdr) {
+        countlists++;
+        countIlists++;
+    }
+
+    list() :
+        nil(true) {
+        countlists++;
+        countElists++;
+    }
+
+    list(const list& p) :
+        nil(p.nil), car(p.car), cdr(p.cdr) {
+        countlists++;
+        countClists++;
+    }
+
+    const list& operator=(const list<T>& p) {
+        if(this == &p)
+            return *this;
+        nil = p.nil;
+        car = p.car;
+        cdr = p.cdr;
+        return *this;
+    }
+
+    ~list() {
+        countlists--;
+    }
+
+    const bool operator==(const list<T>& p) const {
+        if(this == &p)
+            return true;
+        if(nil)
+            return p.nil;
+        if(p.nil)
+            return false;
+        if(!(car == p.car))
+            return false;
+        if(cdr == p.cdr)
+            return true;
+        return cdr() == p.cdr();
+    }
+
+    const bool operator!=(const list<T>& p) const {
+        return !this->operator==(p);
+    }
+
+    template<typename X> friend ostream& operator<<(ostream&, const list<X>&);
+
+};
+
+/**
+ * Returns true if the given list is nil.
+ */
+template<typename T> const bool isNil(const list<T>& p) {
+    return p.nil;
+}
+
+/**
+ * Write a list to an output stream.
+ */
+template<typename X> ostream& operator<<(ostream& out, const list<X>& l) {
+    if(l == list<X> ())
+        return out << "()";
+    return out << "(" << car(l) << ", " << cdr(l) << ")";
+}
+
+/**
+ * Construct a (lazy) list from a value and a lambda function that returns the cdr.
+ */
+template<typename T> const list<T> cons(const T& car, const lambda<list<T> ()>& cdr) {
+    return list<T> (car, cdr);
+}
+
+/**
+ * Construct a list from a value and a cdr list.
+ */
+template<typename T> const list<T> cons(const T& car, const list<T>& cdr) {
+    return list<T> (car, unit(cdr));
+}
+
+/**
+ * Construct a list of one value.
+ */
+template<typename T> const list<T> makeList(const T& car) {
+    return list<T> (car, unit(list<T> ()));
+}
+
+/**
+ * Construct a list of two values.
+ */
+template<typename T> const list<T> makeList(const T& a, const T& b) {
+    return cons(a, makeList(b));
+}
+
+/**
+ * Construct a list of three values.
+ */
+template<typename T> const list<T> makeList(const T& a, const T& b, const T& c) {
+    return cons(a, cons(b, makeList(c)));
+}
+
+/**
+ * Construct a list of four values.
+ */
+template<typename T> const list<T> makeList(const T& a, const T& b, const T& c, const T& d) {
+    return cons(a, cons(b, cons(c, makeList(d))));
+}
+
+/**
+ * Returns the car of a list.
+ */
+template<typename T> const T car(const list<T>& p) {
+    return p.car;
+}
+
+/**
+ * Returns the cdr of a list.
+ */
+template<typename T> list<T> const cdr(const list<T>& p) {
+    return p.cdr();
+}
+
+/**
+ * Returns the car of the cdr of a list.
+ */
+template<typename T> const T cadr(const list<T>& p) {
+    return car(cdr(p));
+}
+
+/**
+ * Returns the cdr of a cdr of a list.
+ */
+template<typename T> const list<T> cddr(const list<T>& p) {
+    return cdr(cdr(p));
+}
+
+/**
+ * Returns the length of a list.
+ */
+template<typename T> struct lengthRef {
+    const int operator()(const int c, const list<T>& p) {
+        if(isNil(p))
+            return c;
+        return (*this)(c + 1, cdr(p));
+    }
+};
+
+template<typename T> const int length(const list<T>& p) {
+    return lengthRef<T> ()(0, p);
+}
+
+/**
+ * Appends a list and a lambda function returning a list.
+ */
+template<typename T> struct appendCdr {
+    const list<T> a;
+    const lambda<list<T> ()> fb;
+    appendCdr(const list<T>& a, const lambda<list<T> ()>& fb) :
+        a(a), fb(fb) {
+    }
+    const list<T> operator()() const {
+        return append(a, fb);
+    }
+};
+
+template<typename T> const list<T> append(const list<T>&a, const lambda<list<T> ()>& fb) {
+    if(isNil(a))
+        return fb();
+
+    return cons(car(a), lambda<list<T> ()> (appendCdr<T> (cdr(a), fb)));
+}
+
+/**
+ * Appends two lists.
+ */
+template<typename T> const list<T> append(const list<T>&a, const list<T>& b) {
+    return append(a, unit(b));
+}
+
+/**
+ * Map a lambda function on a list.
+ */
+template<typename T, typename R> const list<R> map(const lambda<R(T)>& f, const list<T>& p) {
+    if(isNil(p))
+        return list<R> ();
+    return cons(f(car(p)), map(f, cdr(p)));
+}
+
+/**
+ * Run a reduce lambda function on a list.
+ */
+template<typename T, typename R> struct reduceAccumulate {
+    const lambda<R(R, T)> f;
+    reduceAccumulate(const lambda<R(R, T)>& f) :
+        f(f) {
+    }
+    R operator()(const R& acc, const list<T>& p) const {
+        if(isNil(p))
+            return acc;
+        return (*this)(f(acc, car(p)), cdr(p));
+    }
+};
+
+template<typename T, typename R> const R reduce(const lambda<R(R, T)>& f, const R& initial, const list<T>& p) {
+    return reduceAccumulate<T, R> (f)(initial, p);
+}
+
+/**
+ * Run a filter lambda function on a list.
+ */
+template<typename T> const list<T> filter(const lambda<bool(T)>& f, const list<T>& p) {
+    if(isNil(p))
+        return list<T> ();
+    if(f(car(p))) {
+        const lambda<list<T> (lambda<bool(T)> , list<T> )> ff(filter<T> );
+        return cons(car(p), curry(ff, f, cdr(p)));
+    }
+    return filter(f, cdr(p));
+}
+
+/**
+ * Returns a list pointing to a member of a list.
+ */
+template<typename T> const list<T> member(const T& t, const list<T>& p) {
+    if(isNil(p))
+        return list<T> ();
+    if(t == car(p))
+        return p;
+    return member(t, cdr(p));
+}
+
+/**
+ * Reverse a list.
+ */
+template<typename T> const list<T> reverseIter(const list<T>& acc, const list<T>& p) {
+    if(isNil(p))
+        return acc;
+    return reverseIter(cons(car(p), acc), cdr(p));
+}
+
+template<typename T> const list<T> reverse(const list<T>& p) {
+    return reverseIter(list<T> (), p);
+}
+
+template<typename T> const list<T> seq(const T& start, const T& end);
+
+template<typename T> struct seqGenerate {
+    const T start;
+    const T end;
+    seqGenerate(const T& start, const T&end) :
+        start(start), end(end) {
+    }
+    const list<T> operator()() const {
+        return seq<T> (start, end);
+    }
+};
+
+/**
+ * Returns a sequence of values between the given bounds.
+ */
+template<typename T> const list<T> seq(const T& start, const T& end) {
+    if(start == end)
+        return makeList(start);
+    if(start < end)
+        return cons(start, lambda<list<T> ()> (seqGenerate<T> (start + 1, end)));
+    return cons(start, lambda<list<T> ()> (seqGenerate<T> (start - 1, end)));
+}
+
+/**
+ * Equivalent of the list assoc function.
+ */
+template<typename T> const list<T> assoc(const T& k, const list<list<T> >& p) {
+    if(isNil(p))
+        return list<T> ();
+    if(k == car(car(p)))
+        return car(p);
+    return assoc(k, cdr(p));
+}
+
+}
+#endif /* tuscany_list_hpp */
diff --git a/cpp/sca/runtime/core/src/tuscany/value.hpp b/cpp/sca/runtime/core/src/tuscany/value.hpp
new file mode 100644
index 0000000000..e92a9178ca
--- /dev/null
+++ b/cpp/sca/runtime/core/src/tuscany/value.hpp
@@ -0,0 +1,341 @@
+/*
+ * 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_value_hpp
+#define tuscany_value_hpp
+
+/**
+ * Generic value type.
+ */
+
+#include <string>
+#include <ostream>
+#include "gc.hpp"
+#include "function.hpp"
+#include "list.hpp"
+
+using std::string;
+using std::ostream;
+using std::cout;
+using std::endl;
+
+namespace tuscany
+{
+
+long int countValues = 0;
+long int countEValues = 0;
+long int countCValues = 0;
+long int countVValues = 0;
+
+bool resetValueCounters() {
+    countValues = countEValues = countCValues = countVValues = 0;
+    return true;
+}
+
+bool printValueCounters() {
+    using std::cout;
+    using std::endl;
+    cout << "countValues " << countValues << endl;
+    cout << "countEValues " << countEValues << endl;
+    cout << "countCValues " << countCValues << endl;
+    cout << "countVValues " << countVValues << endl;
+    return true;
+}
+
+class Value;
+
+class Value {
+public:
+
+    enum ValueType {
+        Undefined, Symbol, String, List, Number, Boolean, Character, Lambda
+    };
+
+    Value() :
+        type(Value::Undefined) {
+        countValues++;
+        countEValues++;
+    }
+
+    Value(const Value& v) {
+        countValues++;
+        countCValues++;
+        type = v.type;
+        switch(type) {
+        case Value::List:
+            lst() = v.lst();
+        case Value::Lambda:
+            func() = v.func();
+        case Value::Symbol:
+            str() = v.str();
+        case Value::String:
+            str() = v.str();
+        case Value::Number:
+            num() = v.num();
+        case Value::Boolean:
+            boo() = v.boo();
+        case Value::Character:
+            chr() = v.chr();
+        default:
+            break;
+        }
+    }
+
+    const Value& operator=(const Value& v) {
+        if(this == &v)
+            return *this;
+        type = v.type;
+        switch(type) {
+        case Value::List:
+            lst() = v.lst();
+        case Value::Lambda:
+            func() = v.func();
+        case Value::Symbol:
+            str() = v.str();
+        case Value::String:
+            str() = v.str();
+        case Value::Number:
+            num() = v.num();
+        case Value::Boolean:
+            boo() = v.boo();
+        case Value::Character:
+            chr() = v.chr();
+        default:
+            break;
+        }
+        return *this;
+    }
+
+    virtual ~Value() {
+        countValues--;
+    }
+
+    Value(const lambda<Value(list<Value>&)>& func) :
+        type(Value::Lambda), data(vdata(func)) {
+        countValues++;
+        countVValues++;
+    }
+
+    Value(const string& str) :
+        type(Value::String), data(vdata(unit(str))) {
+        countValues++;
+        countVValues++;
+    }
+
+    Value(const char* str) :
+        type(Value::Symbol), data(vdata(unit(string(str)))) {
+        countValues++;
+        countVValues++;
+    }
+
+    Value(const list<Value>& lst) :
+        type(Value::List), data(vdata(unit(lst))) {
+        countValues++;
+        countVValues++;
+    }
+
+    Value(const double num) :
+        type(Value::Number), data(vdata(unit(num))) {
+        countValues++;
+        countVValues++;
+    }
+
+    Value(const int num) :
+        type(Value::Number), data(vdata(unit((double)num))) {
+        countValues++;
+        countVValues++;
+    }
+
+    Value(const bool boo) :
+        type(Value::Boolean), data(vdata(unit(boo))) {
+        countValues++;
+        countVValues++;
+    }
+
+    Value(const char chr) :
+        type(Value::Character), data(vdata(unit(chr))) {
+        countValues++;
+        countVValues++;
+    }
+
+    const bool operator!=(const Value& v) const {
+        return !this->operator==(v);
+    }
+
+    const bool operator==(const Value& v) const {
+        if(this == &v)
+            return true;
+        if(type != v.type)
+            return false;
+        switch(type) {
+        case Value::Undefined:
+            return true;
+        case Value::List:
+            return lst()() == v.lst()();
+        case Value::Lambda:
+            return func() == v.func();
+        case Value::Symbol:
+            return str()() == v.str()();
+        case Value::String:
+            return str()() == v.str()();
+        case Value::Number:
+            return num()() == v.num()();
+        case Value::Boolean:
+            return boo()() == v.boo()();
+        case Value::Character:
+            return chr()() == v.chr()();
+        default:
+            return false;
+        }
+    }
+
+    const Value operator()(list<Value>& args) const {
+        return func()(args);
+    }
+
+    operator string() const {
+        return str()();
+    }
+
+    operator double() const {
+        return num()();
+    }
+
+    operator int() const {
+        return num()();
+    }
+
+    operator bool() const {
+        return boo()();
+    }
+
+    operator char() const {
+        return chr()();
+    }
+
+    operator list<Value>() const {
+        return lst()();
+    }
+
+    operator lambda<Value(list<Value>&)>() const {
+        return func();
+    }
+
+    friend ostream& operator<<(ostream&, const Value&);
+
+    ValueType type;
+    lambda<char()> data;
+
+private:
+    template<typename T> lambda<T>& vdata() const {
+        return *reinterpret_cast<lambda<T> *> (const_cast<lambda<char()> *> (&data));
+    }
+
+    template<typename T> const lambda<char()>& vdata(const T& v) const {
+        return *reinterpret_cast<const lambda<char()> *> (&v);
+    }
+
+    lambda<double()>& num() const {
+        return vdata<double()> ();
+    }
+
+    lambda<bool()>& boo() const {
+        return vdata<bool()> ();
+    }
+
+    lambda<char()>& chr() const {
+        return vdata<char()> ();
+    }
+
+    lambda<string()>& str() const {
+        return vdata<string()> ();
+    }
+
+    lambda<list<Value>()>& lst() const {
+        return vdata<list<Value>()> ();
+    }
+
+    lambda<Value(list<Value>&)>& func() const {
+        return vdata<Value(list<Value>&)> ();
+    }
+
+};
+
+ostream& operator<<(ostream& out, const Value& v) {
+    switch(v.type) {
+    case Value::List:
+        return out << "List::" << v.lst()();
+    case Value::Lambda:
+        return out << "Lambda::" << v.func();
+    case Value::Symbol:
+        return out << "Symbol::" << v.str()();
+    case Value::String:
+        return out << "String::" << '\'' << v.str()() << '\'';
+    case Value::Number:
+        return out << "Number::" << v.num()();
+    case Value::Boolean:
+        if(v.boo()())
+            return out << "Boolean::" << "true";
+        else
+            return out << "Boolean::" << "false";
+    case Value::Character:
+        return out << "Character::" << v.chr()();
+    default:
+        return out << "Undefined";
+    }
+}
+
+const bool isNull(const Value& value) {
+    return value.type == Value::Undefined;
+}
+
+const bool isString(const Value& value) {
+    return value.type == Value::String;
+}
+
+const bool isSymbol(const Value& value) {
+    return value.type == Value::Symbol;
+}
+
+const bool isList(const Value& value) {
+    return value.type == Value::List;
+}
+
+const bool isNumber(const Value& value) {
+    return value.type == Value::Number;
+}
+
+const bool isBoolean(const Value& value) {
+    return value.type == Value::Boolean;
+}
+
+const bool isCharacter(const Value& value) {
+    return value.type == Value::Character;
+}
+
+const bool isTaggedList(const Value& exp, Value tag) {
+    if(isList(exp))
+        return car((list<Value> )exp) == tag;
+    return false;
+}
+
+}
+#endif /* tuscany_value_hpp */