1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
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) || isNull(v) || car(v) != element));
}
/**
* Return true if a value is an attribute.
*/
function isAttribute(v) {
return (!(!isList(v) || isNull(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 !isNull(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)) && !isNull(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 isNull(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)) || isNull(v) || !isSymbol(car(v)));
}
function elementToValueGroupValues(v, l) {
if (isNull(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 (isNull(e))
return e;
return elementToValueGroupValues(elementToValue(car(e)), elementsToValues(cdr(e)));
}
/**
* Convert a value to an element.
*/
function valueToElement(t) {
if (isList(t) && !isNull(t) && isSymbol(car(t))) {
var n = car(t);
var v = isNull(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 (isNull(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 (isNull(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 (isNull(s))
return true;
if (isNull(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 (isNull(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 (isNull(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 = {};
}
|
