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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_element_hpp
#define tuscany_element_hpp
/**
* Functions to help represent data as lists of elements and attributes.
*/
#include "list.hpp"
#include "value.hpp"
namespace tuscany
{
/**
* Tags used to tag lists of elements and attributes.
*/
const value attribute("attribute");
const value element("element");
const string atsign("@");
/**
* Returns true if a value is an element.
*/
inline const bool isElement(const value& v) {
if (!isList(v) || isNull(v) || element != car<value>(v))
return false;
return true;
}
/**
* Returns true if a value is an attribute.
*/
inline const bool isAttribute(const value& v) {
if (!isList(v) || isNull(v) || attribute != car<value>(v))
return false;
return true;
}
/**
* Returns the name of an attribute.
*/
inline const value attributeName(const list<value>& l) {
return cadr(l);
}
/**
* Returns the value of an attribute.
*/
inline const value attributeValue(const list<value>& l) {
return caddr(l);
}
/**
* Returns the name of an element.
*/
inline const value elementName(const list<value>& l) {
return cadr(l);
}
/**
* Returns true if an element has children.
*/
inline const bool elementHasChildren(const list<value>& l) {
return !isNull(cddr(l));
}
/**
* Returns the children of an element.
*/
inline const list<value> elementChildren(const list<value>& l) {
return cddr(l);
}
/**
* Returns true if an element has a value.
*/
inline const bool elementHasValue(const list<value>& l) {
const list<value> r = reverse(l);
if (isSymbol(car(r)))
return false;
if(isList(car(r)) && !isNull((list<value>)car(r)) && isSymbol(car<value>(car(r))))
return false;
return true;
}
/**
* Returns the value of an element.
*/
inline const value elementValue(const list<value>& l) {
return car(reverse(l));
}
/**
* Convert an element to a value.
*/
inline const bool elementToValueIsList(const value& v) {
if (!isList(v))
return false;
const list<value> l = v;
return (isNull(l) || !isSymbol(car(l)));
}
inline const value elementToValue(const value& t) {
const list<value> elementsToValues(const list<value>& e);
// Convert an attribute
if (isTaggedList(t, attribute))
return mklist<value>(c_str(atsign + (string)attributeName(t)), attributeValue(t));
// Convert an element
if (isTaggedList(t, element)) {
// Convert an element's value
if (elementHasValue(t)) {
// Convert a single value
if (!elementToValueIsList(elementValue(t)))
return mklist(elementName(t), elementValue(t));
// Convert a list value
return cons(elementName(t), mklist<value>(elementsToValues(elementValue(t))));
}
// Convert an element's children
return cons(elementName(t), elementsToValues(elementChildren(t)));
}
// Convert a value
if (!isList(t))
return t;
return elementsToValues(t);
}
/**
* Convert a list of elements to a list of values.
*/
inline const bool elementToValueIsSymbol(const value& v) {
if (!isList(v))
return false;
const list<value> l = v;
if (isNull(l))
return false;
if (!isSymbol(car(l)))
return false;
return true;
}
inline const list<value> elementToValueGroupValues(const value& v, const list<value>& l) {
if (isNull(l) || !elementToValueIsSymbol(v) || !elementToValueIsSymbol(car(l)))
return cons(v, l);
if (car<value>(car(l)) != car<value>(v))
return cons(v, l);
if (!elementToValueIsList(cadr<value>(car(l)))) {
const value g = mklist<value>(car<value>(v), mklist<value>(isList(cadr<value>(v))? (value)cdr<value>(v) : cadr<value>(v), isList(cadr<value>(car(l)))? (value)cdr<value>(car(l)) : cadr<value>(car(l))));
return elementToValueGroupValues(g, cdr(l));
}
const value g = mklist<value>(car<value>(v), cons<value>(isList(cadr<value>(v))? (value)cdr<value>(v) : cadr<value>(v), (list<value>)cadr<value>(car(l))));
return elementToValueGroupValues(g, cdr(l));
}
inline const list<value> elementsToValues(const list<value>& e) {
if (isNull(e))
return e;
return elementToValueGroupValues(elementToValue(car(e)), elementsToValues(cdr(e)));
}
/**
* Convert a value to an element.
*/
inline const value valueToElement(const value& t) {
const list<value> valuesToElements(const list<value>& l);
// Convert a name value pair
if (isList(t) && !isNull((list<value>)t) && isSymbol(car<value>(t))) {
const value n = car<value>(t);
const value v = isNull(cdr<value>(t))? nilValue : cadr<value>(t);
// Convert a single value to an attribute or an element
if (!isList(v)) {
if (substr(n, 0, 1) == atsign)
return mklist<value>(attribute, c_str(substr(n, 1)), v);
return mklist(element, n, v);
}
// Convert a list value
if (isNull((list<value>)v) || !isSymbol(car<value>(v)))
return cons(element, cons(n, mklist<value>(valuesToElements(v))));
// Convert a nested name value pair value
return cons(element, cons(n, valuesToElements(cdr<value>(t))));
}
// Convert a value
if (!isList(t))
return t;
return valuesToElements(t);
}
/**
* Convert a list of values to a list of elements.
*/
inline const list<value> valuesToElements(const list<value>& l) {
if (isNull(l))
return l;
return cons<value>(valueToElement(car(l)), valuesToElements(cdr(l)));
}
/**
* Returns the value of the attribute with the given name.
*/
inline const value attributeValue(const value& name, const list<value>& l) {
const list<value> f = filter<value>([name](const value& v) {
return isAttribute(v) && attributeName((list<value>)v) == name;
}, l);
if (isNull(f))
return nilValue;
return caddr<value>(car(f));
}
/**
* Returns child elements with the given name.
*/
inline const list<value> elementChildren(const value& name, const list<value>& l) {
return filter<value>([name](const value& v) {
return isElement(v) && elementName((list<value>)v) == name;
}, l);
}
/**
* Return the child element with the given name.
*/
inline const value elementChild(const value& name, const list<value>& l) {
const list<value> f = elementChildren(name, l);
if (isNull(f))
return nilValue;
return car(f);
}
}
#endif /* tuscany_element_hpp */
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