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/* --- Tree representation -------------------------------------------------- */
function Node(value, children) {
this.value = value;
this.children = [];
if (children != undefined)
for (c in children)
this.children.push( new Node(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 Tree(value) {
this.root = new Node(value, []);
// add value as child of id
this.add = function(id, value, children) {
var x = this.find(id);
x.children.push( new Node(value, children) );
}
// set tree at given id to
this.setSubtree = function(id, node) {
var x = this.find(id);
x.value = node.value;
x.children = node.children;
}
// 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 id = undefined
switch (typeof _id) {
case "number": id = [_id]; break;
case "string": id = _id.split(","); break;
case "object": id = _id.get().slice(); break; // clone NodeID array
}
var node = this.root;
if (id[0] == 0) id.shift();
while (id.length>0 && node.children.length>0) {
node = node.children[id.shift()];
}
if (id.length>0)
return undefined;
return node;
}
// generic HOF for traversing tree
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);
}
}
/* --- 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 AST(fun, cat) {
function ASTNode(fun, cat) {
this.fun = fun;
this.cat = cat;
}
this.tree = new Tree(new ASTNode(fun, cat));
this.current = new NodeID(); // current id in tree
this.getFun = function() {
return this.tree.find(this.current).value.fun;
}
this.setFun = function(f) {
this.tree.find(this.current).value.fun = f;
}
this.getCat = function() {
return this.tree.find(this.current).value.cat;
}
this.setCat = function(c) {
this.tree.find(this.current).value.cat = c;
}
// Add a single fun at current node
this.add = function(fun, cat) {
this.tree.add(this.current, new ASTNode(fun,cat));
}
// Set entire subtree at current node
this.setSubtree = function(node) {
this.tree.setSubtree(this.current, node);
}
// Clear children of current node
this.removeChildren = function() {
this.tree.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.tree.find(id);
// first check children
for (i in node.children) {
var child = node.children[i];
if (!child.value.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);
}
//
this.traverse = function(f) {
this.tree.traverse(f);
}
// Return tree as string
this.toString = function() {
var s = "";
function visit(node) {
s += node.value.fun ? node.value.fun : "?" ;
if (node.children.length == 0)
return;
for (i in node.children) {
s += " (";
visit(node.children[i]);
s += ")";
}
}
visit(this.tree.root);
return s;
}
// Parse AST string into node tree
this.parseTree = function(str) {
function trim(str) {
return str.trim().replace(/^\(\s*(.*)\s*\)$/, "$1");
}
function visit(node, str) {
var parts = [];
var ix_last = 0;
var par_cnt = 0;
for (i in str) {
if (str[i] == " ") {
if (par_cnt == 0) {
parts.push(trim(str.substring(ix_last, i)));
ix_last = i;
}
}
else if (str[i] == "(")
par_cnt++;
else if (str[i] == ")")
par_cnt--;
}
parts.push(trim(str.substring(ix_last)));
var fun = parts.shift();
var cat = null; // will be filled later
node.value = new ASTNode(fun, cat);
for (i in parts) {
node.children.push(new Node());
visit(node.children[i], parts[i]);
}
}
var tree = new Node();
visit(tree, str);
return tree;
}
}
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