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Diffstat (limited to 'sca-cpp/branches/lightweight-sca/kernel/element.hpp')
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diff --git a/sca-cpp/branches/lightweight-sca/kernel/element.hpp b/sca-cpp/branches/lightweight-sca/kernel/element.hpp new file mode 100644 index 0000000000..27b5af8691 --- /dev/null +++ b/sca-cpp/branches/lightweight-sca/kernel/element.hpp @@ -0,0 +1,304 @@ +/* + * 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. + */ +bool isElement(const value& v) { + if (!isList(v) || isNil(v) || element != car<value>(v)) + return false; + return true; +} + +/** + * Returns true if a value is an attribute. + */ +bool isAttribute(const value& v) { + if (!isList(v) || isNil(v) || attribute != car<value>(v)) + return false; + return true; +} + +/** + * Returns the name of an attribute. + */ +const value attributeName(const list<value>& l) { + return cadr(l); +} + +/** + * Returns the value of an attribute. + */ +const value attributeValue(const list<value>& l) { + return caddr(l); +} + +/** + * Returns the name of an element. + */ +const value elementName(const list<value>& l) { + return cadr(l); +} + +/** + * Returns true if an element has children. + */ +const bool elementHasChildren(const list<value>& l) { + return !isNil(cddr(l)); +} + +/** + * Returns the children of an element. + */ +const list<value> elementChildren(const list<value>& l) { + return cddr(l); +} + +/** + * Returns true if an element has a value. + */ +const bool elementHasValue(const list<value>& l) { + const list<value> r = reverse(l); + if (isSymbol(car(r))) + return false; + if(isList(car(r)) && !isNil((list<value>)car(r)) && isSymbol(car<value>(car(r)))) + return false; + return true; +} + +/** + * Returns the value of an element. + */ +const value elementValue(const list<value>& l) { + return car(reverse(l)); +} + +/** + * Convert an element to a value. + */ +const bool elementToValueIsList(const value& v) { + if (!isList(v)) + return false; + const list<value> l = v; + return (isNil(l) || !isSymbol(car(l))); +} + +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 + 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. + */ +const bool elementToValueIsSymbol(const value& v) { + if (!isList(v)) + return false; + const list<value> l = v; + if (isNil(l)) + return false; + if (!isSymbol(car(l))) + return false; + return true; +} + +const list<value> elementToValueGroupValues(const value& v, const list<value>& l) { + if (isNil(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)); + +} + +const list<value> elementsToValues(const list<value>& e) { + if (isNil(e)) + return e; + return elementToValueGroupValues(elementToValue(car(e)), elementsToValues(cdr(e))); +} + +/** + * Convert a value to an element. + */ +const value valueToElement(const value& t) { + const list<value> valuesToElements(const list<value>& l); + + // Convert a name value pair + if (isList(t) && !isNil((list<value>)t) && isSymbol(car<value>(t))) { + const value n = car<value>(t); + const value v = isNil(cdr<value>(t))? value() : 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 (isNil((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. + */ +const list<value> valuesToElements(const list<value>& l) { + if (isNil(l)) + return l; + return cons<value>(valueToElement(car(l)), valuesToElements(cdr(l))); +} + +/** + * Returns a selector lambda function which can be used to filter + * elements against the given element pattern. + */ +struct selectorLambda { + const list<value> select; + selectorLambda(const list<value>& s) : select(s) { + } + const bool evalSelect(const list<value>& s, const list<value> v) const { + if (isNil(s)) + return true; + if (isNil(v)) + return false; + if (car(s) != car(v)) + return false; + return evalSelect(cdr(s), cdr(v)); + } + const bool operator()(const value& v) const { + if (!isList(v)) + return false; + return evalSelect(select, v); + } +}; + +const lambda<bool(const value&)> selector(const list<value> s) { + return selectorLambda(s); +} + +/** + * Returns the value of the attribute with the given name. + */ +struct filterAttribute { + const value name; + filterAttribute(const value& n) : name(n) { + } + const bool operator()(const value& v) const { + return isAttribute(v) && attributeName((list<value>)v) == name; + } +}; + +const value attributeValue(const value& name, const value& l) { + const list<value> f = filter<value>(filterAttribute(name), list<value>(l)); + if (isNil(f)) + return value(); + return caddr<value>(car(f)); +} + +/** + * Returns child elements with the given name. + */ +struct filterElement { + const value name; + filterElement(const value& n) : name(n) { + } + const bool operator()(const value& v) const { + return isElement(v) && elementName((list<value>)v) == name; + } +}; + +const value elementChildren(const value& name, const value& l) { + return filter<value>(filterElement(name), list<value>(l)); +} + +/** + * Return the child element with the given name. + */ +const value elementChild(const value& name, const value& l) { + const list<value> f = elementChildren(name, l); + if (isNil(f)) + return value(); + return car(f); +} + +} +#endif /* tuscany_element_hpp */ |