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Diffstat (limited to 'sca-cpp/branches/lightweight-sca/modules/js/htdocs/elemutil.js')
| -rw-r--r-- | sca-cpp/branches/lightweight-sca/modules/js/htdocs/elemutil.js | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/sca-cpp/branches/lightweight-sca/modules/js/htdocs/elemutil.js b/sca-cpp/branches/lightweight-sca/modules/js/htdocs/elemutil.js new file mode 100644 index 0000000000..37d641f7b3 --- /dev/null +++ b/sca-cpp/branches/lightweight-sca/modules/js/htdocs/elemutil.js @@ -0,0 +1,236 @@ +/* + * 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. + */ + +/** + * Functions to help represent data as lists of elements and attributes. + */ + +var element = "'element" +var attribute = "'attribute" +var atsign = "'@" + +/** + * Return true if a value is an element. + */ +function isElement(v) { + return (!(!isList(v) || isNil(v) || car(v) != element)); +} + +/** + * Return true if a value is an attribute. + */ +function isAttribute(v) { + return (!(!isList(v) || isNil(v) || car(v) != attribute)); +} + +/** + * Return the name of an attribute. + */ +attributeName = cadr; + +/** + * Return the value of an attribute. + */ +attributeValue = caddr; + +/** + * Return the name of an element. + */ +elementName = cadr; + +/** + * Return true if an element has children. + */ +function elementHasChildren(l) { + return !isNil(cddr(l)); +} + +/** + * Return the children of an element. + */ +elementChildren = cddr; + +/** + * Return true if an element has a value. + */ +function elementHasValue(l) { + var r = reverse(l); + if (isSymbol(car(r))) + return false; + return (!(isList(car(r)) && !isNil(car(r)) && isSymbol(car(car(r))))) +} + +/** + * Return the value of an element. + */ +function elementValue(l) { + return car(reverse(l)); +} + +/** + * Convert an element to a value. + */ +function elementToValueIsList(v) { + if (!isList(v)) + return false; + return isNil(v) || !isSymbol(car(v)); +} + +function elementToValue(t) { + if (isTaggedList(t, attribute)) + return mklist(atsign + attributeName(t).substring(1), attributeValue(t)); + if (isTaggedList(t, element)) { + if (elementHasValue(t)) { + if (!elementToValueIsList(elementValue(t))) + return mklist(elementName(t), elementValue(t)); + return cons(elementName(t), mklist(elementsToValues(elementValue(t)))); + } + return cons(elementName(t), elementsToValues(elementChildren(t))); + } + if (!isList(t)) + return t; + return elementsToValues(t); +} + +/** + * Convert a list of elements to a list of values. + */ +function elementToValueIsSymbol(v) { + return (!(!isList(v)) || isNil(v) || !isSymbol(car(v))); +} + +function elementToValueGroupValues(v, l) { + if (isNil(l) || !elementToValueIsSymbol(v) || !elementToValueIsSymbol(car(l))) + return cons(v, l); + if (car(car(l)) != car(v)) + return cons(v, l); + if (!elementToValueIsList(cadr(car(l)))) { + var g = mklist(car(v), mklist(cdr(v), cdr(car(l)))); + return elementToValueGroupValues(g, cdr(l)); + } + var g = mklist(car(v), cons(cdr(v), cadr(car(l)))); + return elementToValueGroupValues(g, cdr(l)); +} + +function elementsToValues(e) { + if (isNil(e)) + return e; + return elementToValueGroupValues(elementToValue(car(e)), elementsToValues(cdr(e))); +} + +/** + * Convert a value to an element. + */ +function valueToElement(t) { + if (isList(t) && !isNil(t) && isSymbol(car(t))) { + var n = car(t); + var v = isNil(cdr(t))? mklist() : cadr(t); + if (!isList(v)) { + if (n.substring(0, 2) == atsign) + return mklist(attribute, "'" + n.substring(2), v); + return mklist(element, n, v); + } + if (isNil(v) || !isSymbol(car(v))) + return cons(element, cons(n, mklist(valuesToElements(v)))); + return cons(element, cons(n, valuesToElements(cdr(t)))); + } + if (!isList(t)) + return t; + return valuesToElements(t); +} + +/** + * Convert a list of values to a list of elements. + */ +function valuesToElements(l) { + if (isNil(l)) + return l; + return cons(valueToElement(car(l)), valuesToElements(cdr(l))); +} + +/** + * Return a selector lambda function which can be used to filter elements. + */ +function selector(s) { + function evalSelect(s, v) { + if (isNil(s)) + return true; + if (isNil(v)) + return false; + if (car(s) != car(v)) + return false; + return evalSelect(cdr(s), cdr(v)); + } + + return function(v) { return evalSelect(s, v); }; +} + +/** + * Return the attribute with the given name. + */ +function namedAttribute(name, l) { + return memo(l, name, function() { + var f = filter(function(v) { return isAttribute(v) && attributeName(v) == name; }, l); + if (isNil(f)) + return null; + return car(f); + }); +} + +/** + * Return the value of the attribute with the given name. + */ +function namedAttributeValue(name, l) { + var a = namedAttribute(name, l); + if (a == null) + return null + return attributeValue(a); +} + +/** + * Return child elements with the given name. + */ +function namedElementChildren(name, l) { + return memo(l, name, function() { + return filter(function(v) { return isElement(v) && elementName(v) == name; }, l); + }); +} + +/** + * Return the child element with the given name. + */ +function namedElementChild(name, l) { + var f = namedElementChildren(name, l); + if (isNil(f)) + return null; + return car(f); +} + +/** + * Side effect functions. Use with moderation. + */ + +/** + * Set the contents of an element. + */ +function setElement(l, e) { + setlist(l, e); + l.memo = {}; +} + |