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/* --- ID for a node in a tree ---------------------------------------------- */
function NodeID(x) {
this.id = new Array();
this.id.push(0);
// Initialize from input
if (x) {
switch (typeof x) {
case "number": this.id = [x]; break;
case "string": this.id = map(function(s){return parseInt(s)}, x.split(",")); break;
case "object": this.id = x.get().slice(); break; // another NodeID
}
}
// get id
this.get = function() {
return this.id;
}
// Add child node to id
this.add = function(x) {
this.id.push(parseInt(x));
return this.id;
}
// compare with other id
this.equals = function(other) {
return JSON.stringify(this.id)==JSON.stringify(other.id);
}
}
/* --- Abstract Syntax Tree (with state)------------------------------------- */
function ASTNode(data) {
for(var d in data) this[d]=data[d];
this.children = [];
for (c in data.children) {
this.children.push( new ASTNode(data.children[c]) );
}
this.hasChildren = function(){
return this.children.length > 0;
}
// generic HOF for traversing tree
this.traverse = function(f) {
function visit(node) {
f(node);
for (i in node.children) {
visit(node.children[i]);
}
}
visit(this);
}
}
function AST(fun, cat) {
// local helper function for building ASTNodes
newNode = function(fun, cat) {
return new ASTNode({
"fun": fun,
"cat": cat,
"children": []
});
}
this.root = newNode(fun, cat);
this.current = new NodeID(); // current id in tree
this.getFun = function() {
return this.find(this.current).fun;
}
this.setFun = function(f) {
this.find(this.current).fun = f;
}
this.getCat = function() {
return this.find(this.current).cat;
}
this.setCat = function(c) {
this.find(this.current).cat = c;
}
// Add a single fun at current node
this.add = function(fun, cat) {
this._add(this.current, newNode(fun,cat));
}
// add node as child of id
this._add = function(id, node) {
var x = this.find(id);
x.children.push(node);
}
// Set entire subtree at current node
this.setSubtree = function(node) {
this._setSubtree(this.current, node);
}
// set tree at given id
this._setSubtree = function(id, subtree) {
var lid = id.get().slice(); // clone NodeID array
var node = this.root;
if (lid.length==1)
// Insert at root
this.root = new ASTNode(subtree);
else {
lid.shift(); // throw away root
while (lid.length>1 && node.hasChildren()) {
node = node.children[lid.shift()];
}
node.children[lid.shift()] = new ASTNode(subtree);
}
}
// id should be a list of child indices [0,1,0]
// or a string separated by commas "0,1,0"
this.find = function(id) {
var lid = undefined
switch (typeof id) {
case "number": lid = [id]; break;
case "string": lid = id.split(","); break;
case "object": lid = id.get().slice(); break; // clone NodeID array
}
var node = this.root;
if (lid[0] == 0) lid.shift();
while (lid.length>0 && node.children.length>0) {
node = node.children[lid.shift()];
}
if (lid.length>0)
return undefined;
return node;
}
// Clear children of current node
this.removeChildren = function() {
this.find(this.current).children = [];
}
// Move current ID to next hole
this.toNextHole = function() {
var id = new NodeID(this.current);
// loop until we're at top
while (id.get().length > 0) {
var node = this.find(id);
// first check children
for (i in node.children) {
var child = node.children[i];
if (!child.fun) {
var newid = new NodeID(id);
newid.add(i);
this.current = newid;
return;
}
}
// otherwise go up to parent
id.get().pop();
}
}
// Move current id to child number i
this.toChild = function(i) {
this.current.add(i);
}
// generic HOF for traversing tree
// this.traverse = function(f) {
// this.root.traverse(f);
// }
this.traverse = function(f) {
function visit(id, node) {
f(node);
for (i in node.children) {
var newid = new NodeID(id);
newid.add(parseInt(i));
visit(newid, node.children[i]);
}
}
visit(new NodeID(), this.root);
}
// Return tree as string
this.toString = function() {
var s = "";
function visit(node) {
s += node.fun ? node.fun : "?" ;
if (!node.hasChildren())
// if (node.children.length == 0)
return;
for (i in node.children) {
s += " (";
visit(node.children[i]);
s += ")";
}
}
visit(this.root);
return s;
}
}
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