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Increment digit part of string in JavaScript

I have a string that contains digit at the end. I want to increase the digit part by 1 when some actions happened.
e.g.
var myString = 'AA11111'
increaseStringValue(myString)
# myString new value => 'AA11112'
also how can I increase chars when string value reached to 'AA99999' so new value of string will be 'AB11111'?

You can split char and digit parts so you can handle them separately.
like:
function increaseStringValue(str){
let charPart = str.substring(0,2);
let digitPart = str.substring(2);
digitPart = +digitPart+1
if(digitPart >= 99999){
digitPart = 11111;
if(charPart[1] == 'Z'){
if(charPart[0] == 'Z'){
throw 'Overflow happened'
}
charPart = String.fromCharCode(charPart.charCodeAt(0)+1) + 'A'
}else{
charPart = charPart[0] + String.fromCharCode(charPart.charCodeAt(1)+1)
}
}
return charPart + digitPart;
}
increaseStringValue('AA11111'); // 'AA11112'
increaseStringValue('AA99999'); // 'AB11111'
increaseStringValue('AZ99999'); // 'BA11111'
increaseStringValue('ZZ99999'); // Exception: Overflow happened
This links will be helpful for you:
ASCII CODES
what is a method that can be used to increment letters?
Edit:
Following function will be suite for unknown length string with dynamic position of char and digit.
function increaseStringValue(str) {
let charOverFlowed = true;
let result = ""
for (let i = str.length - 1; i >= 0; i--) {
let currentChar = str[i];
if ('123456789'.indexOf(currentChar) !== -1) {
if (charOverFlowed) {
currentChar = +currentChar + 1
charOverFlowed = false;
}
if (currentChar > 9) {
currentChar = 1;
charOverFlowed = true;
}
} else if (charOverFlowed) {
currentChar = String.fromCharCode(currentChar.charCodeAt(0) + 1)
charOverFlowed = false;
if (currentChar > 'Z') {
if(i == 0){
throw 'Overflow Happened'
}
currentChar = 'A'
charOverFlowed = true
}
}
result = currentChar + result;
}
return result;
}
increaseStringValue('AAAACA')
// "AAAACB"
increaseStringValue('AAAACA1111')
// "AAAACA1112"
increaseStringValue('A1')
// "A2"
increaseStringValue('Z')
// Uncaught Overflow Happened
increaseStringValue('A1999')
// "A2111"

function increaseStringValue(myString){
return myString.replace(/\d+/ig, function(a){ return a*1+1;});
}
console.log(increaseStringValue("asg61"));
And for next question:
function increaseStringValue(myString){
return myString.replace(/(A)(\d+)/ig, function(a, b, c){
var r = c*1+1; return r==99999+1?"B11111":"A"+r;
});
}
console.log(increaseStringValue("AA99999"));
And Whole way:
function increaseStringValue(myString){
return myString.replace(/([a-e])(\d+)/ig, function(a, b, c){
var r = c*1+1; return r==99999+1?String.fromCharCode(a.charCodeAt(0)+1)+"11111":b+r;
});
}
console.log(increaseStringValue("AB99999"));

Please find the snippet useful. If this is what you are expecting.
let stringNum = 'AA11111';//initialise string
let clickTriggered = ()=>{
let startString = "AA";
let newNum = ()=>{
let numberPart = stringNum.split("AA")[1];
let lastChar = stringNum[stringNum.length-1];
return Number(numberPart) != NaN || Number(numberPart) <= 99999 ? Number(numberPart)+1 : 11111;
};
stringNum = `${startString}${newNum()}`
console.log(stringNum)
}
<h1 onclick="clickTriggered()">click here</h1>

You can use String#replace and provide your increment logic in the function callback of the string#replace.
const increaseStringValue = (str) => str.replace(/\d+$/, n => n === '99999' ? 11111 : +n + 1);
console.log(increaseStringValue('AA99999'));
console.log(increaseStringValue('AA11315'));
console.log(increaseStringValue('AA11111'));

I solve this with this solution
let app = new Vue({
el: '#app',
data: {
text: "AA995"
},
methods: {
addOneString: function(str) {
var alphabet = 'abcdefghijklmnopqrstuvwxyz',
length = alphabet.length,
result = str,
i = str.length,
value = str;
while(i >= 0) {
var last = str.charAt(--i),
next = '',
carry = false;
if (isNaN(last)) {
index = alphabet.indexOf(last.toLowerCase());
if (index === -1) {
next = last;
carry = true;
}
else {
var isUpperCase = last === last.toUpperCase();
next = alphabet.charAt((index + 1) % length);
if (isUpperCase) {
next = next.toUpperCase();
}
carry = index + 1 >= length;
if (carry && i === 0) {
var added = isUpperCase ? 'A' : 'a';
result = added + next + result.slice(1);
break;
}
}
}
else {
next = +last + 1;
if(next > 9) {
next = 0;
carry = true;
}
if (carry && i === 0) {
result = '1' + next + result.slice(1);
break;
}
}
result = result.slice(0, i) + next + result.slice(i + 1);
if (!carry) {
break;
}
}
console.log("result",result);
if (value !== result ) this.text = result;
}
}
})
<script src="https://unpkg.com/vue/dist/vue.js"></script>
<div class="container" id="app">
<button #click="addOneString(text)">Add one</button>
</br>
<p> {{text}} </p>
</div>

How to convert from Path to XPath, given a browser event

On a MouseEvent instance, we have a property called path, it might look like this:
Does anybody know if there is a reliable way to translate this path array into an XPath? I assume that this path data is the best data to start from? Is there a library I can use to do the conversion?
This library looks promising, but it doesn't use the path property of an event: https://github.com/johannhof/xpath-dom

There's not a unique XPath to a node, so you'll have to decide what's the most appropriate way of constructing a path. Use IDs where available? Numeral position in the document? Position relative to other elements?
See getPathTo() in this answer for one possible approach.
PS: Taken from Javascript get XPath of a node
Another option is to use SelectorGadget from below link
https://dv0akt2986vzh.cloudfront.net/unstable/lib/selectorgadget.js
The actual code for the DOM path is at
https://dv0akt2986vzh.cloudfront.net/stable/lib/dom.js
Usage: on http://google.com
elem = document.getElementById("q")
predict = new DomPredictionHelper()
predict.pathOf(elem)
// gives "body.default-theme.des-mat:nth-child(2) div#_Alw:nth-child(4) form#f:nth-child(2) div#fkbx:nth-child(2) input#q:nth-child(2)"
predict.predictCss([elem],[])
// gives "#q"
CODE if link goes down
// Copyright (c) 2008, 2009 Andrew Cantino
// Copyright (c) 2008, 2009 Kyle Maxwell
function DomPredictionHelper() {};
DomPredictionHelper.prototype = new Object();
DomPredictionHelper.prototype.recursiveNodes = function(e){
var n;
if(e.nodeName && e.parentNode && e != document.body) {
n = this.recursiveNodes(e.parentNode);
} else {
n = new Array();
}
n.push(e);
return n;
};
DomPredictionHelper.prototype.escapeCssNames = function(name) {
if (name) {
try {
return name.replace(/\s*sg_\w+\s*/g, '').replace(/\\/g, '\\\\').
replace(/\./g, '\\.').replace(/#/g, '\\#').replace(/\>/g, '\\>').replace(/\,/g, '\\,').replace(/\:/g, '\\:');
} catch(e) {
console.log('---');
console.log("exception in escapeCssNames");
console.log(name);
console.log('---');
return '';
}
} else {
return '';
}
};
DomPredictionHelper.prototype.childElemNumber = function(elem) {
var count = 0;
while (elem.previousSibling && (elem = elem.previousSibling)) {
if (elem.nodeType == 1) count++;
}
return count;
};
DomPredictionHelper.prototype.pathOf = function(elem){
var nodes = this.recursiveNodes(elem);
var self = this;
var path = "";
for(var i = 0; i < nodes.length; i++) {
var e = nodes[i];
if (e) {
path += e.nodeName.toLowerCase();
var escaped = e.id && self.escapeCssNames(new String(e.id));
if(escaped && escaped.length > 0) path += '#' + escaped;
if(e.className) {
jQuery.each(e.className.split(/ /), function() {
var escaped = self.escapeCssNames(this);
if (this && escaped.length > 0) {
path += '.' + escaped;
}
});
}
path += ':nth-child(' + (self.childElemNumber(e) + 1) + ')';
path += ' '
}
}
if (path.charAt(path.length - 1) == ' ') path = path.substring(0, path.length - 1);
return path;
};
DomPredictionHelper.prototype.commonCss = function(array) {
try {
var dmp = new diff_match_patch();
} catch(e) {
throw "Please include the diff_match_patch library.";
}
if (typeof array == 'undefined' || array.length == 0) return '';
var existing_tokens = {};
var encoded_css_array = this.encodeCssForDiff(array, existing_tokens);
var collective_common = encoded_css_array.pop();
jQuery.each(encoded_css_array, function(e) {
var diff = dmp.diff_main(collective_common, this);
collective_common = '';
jQuery.each(diff, function() {
if (this[0] == 0) collective_common += this[1];
});
});
return this.decodeCss(collective_common, existing_tokens);
};
DomPredictionHelper.prototype.tokenizeCss = function(css_string) {
var skip = false;
var word = '';
var tokens = [];
var css_string = css_string.replace(/,/, ' , ').replace(/\s+/g, ' ');
var length = css_string.length;
var c = '';
for (var i = 0; i < length; i++){
c = css_string[i];
if (skip) {
skip = false;
} else if (c == '\\') {
skip = true;
} else if (c == '.' || c == ' ' || c == '#' || c == '>' || c == ':' || c == ',') {
if (word.length > 0) tokens.push(word);
word = '';
}
word += c;
if (c == ' ' || c == ',') {
tokens.push(word);
word = '';
}
}
if (word.length > 0) tokens.push(word);
return tokens;
};
DomPredictionHelper.prototype.decodeCss = function(string, existing_tokens) {
var inverted = this.invertObject(existing_tokens);
var out = '';
jQuery.each(string.split(''), function() {
out += inverted[this];
});
return this.cleanCss(out);
};
// Encode css paths for diff using unicode codepoints to allow for a large number of tokens.
DomPredictionHelper.prototype.encodeCssForDiff = function(strings, existing_tokens) {
var codepoint = 50;
var self = this;
var strings_out = [];
jQuery.each(strings, function() {
var out = new String();
jQuery.each(self.tokenizeCss(this), function() {
if (!existing_tokens[this]) {
existing_tokens[this] = String.fromCharCode(codepoint++);
}
out += existing_tokens[this];
});
strings_out.push(out);
});
return strings_out;
};
DomPredictionHelper.prototype.simplifyCss = function(css, selected_paths, rejected_paths) {
var self = this;
var parts = self.tokenizeCss(css);
var best_so_far = "";
if (self.selectorGets('all', selected_paths, css) && self.selectorGets('none', rejected_paths, css)) best_so_far = css;
for (var pass = 0; pass < 4; pass++) {
for (var part = 0; part < parts.length; part++) {
var first = parts[part].substring(0,1);
if (self.wouldLeaveFreeFloatingNthChild(parts, part)) continue;
if ((pass == 0 && first == ':') || // :nth-child
(pass == 1 && first != ':' && first != '.' && first != '#' && first != ' ') || // elem, etc.
(pass == 2 && first == '.') || // classes
(pass == 3 && first == '#')) // ids
{
var tmp = parts[part];
parts[part] = '';
var selector = self.cleanCss(parts.join(''));
if (selector == '') {
parts[part] = tmp;
continue;
}
if (self.selectorGets('all', selected_paths, selector) && self.selectorGets('none', rejected_paths, selector)) {
best_so_far = selector;
} else {
parts[part] = tmp;
}
}
}
}
return self.cleanCss(best_so_far);
};
DomPredictionHelper.prototype.wouldLeaveFreeFloatingNthChild = function(parts, part) {
return (((part - 1 >= 0 && parts[part - 1].substring(0, 1) == ':') &&
(part - 2 < 0 || parts[part - 2] == ' ') &&
(part + 1 >= parts.length || parts[part + 1] == ' ')) ||
((part + 1 < parts.length && parts[part + 1].substring(0, 1) == ':') &&
(part + 2 >= parts.length || parts[part + 2] == ' ') &&
(part - 1 < 0 || parts[part - 1] == ' ')));
};
DomPredictionHelper.prototype.cleanCss = function(css) {
return css.replace(/\>/, ' > ').replace(/,/, ' , ').replace(/\s+/g, ' ').replace(/^\s+|\s+$/g, '').replace(/,$/, '');
};
DomPredictionHelper.prototype.getPathsFor = function(arr) {
var self = this;
var out = [];
jQuery.each(arr, function() {
if (this && this.nodeName) {
out.push(self.pathOf(this));
}
})
return out;
};
DomPredictionHelper.prototype.predictCss = function(s, r) {
var self = this;
if (s.length == 0) return '';
var selected_paths = self.getPathsFor(s);
var rejected_paths = self.getPathsFor(r);
var css = self.commonCss(selected_paths);
var simplest = self.simplifyCss(css, selected_paths, rejected_paths);
// Do we get off easy?
if (simplest.length > 0) return simplest;
// Okay, then make a union and possibly try to reduce subsets.
var union = '';
jQuery.each(s, function() {
union = self.pathOf(this) + ", " + union;
});
union = self.cleanCss(union);
return self.simplifyCss(union, selected_paths, rejected_paths);
};
DomPredictionHelper.prototype.fragmentSelector = function(selector) {
var self = this;
var out = [];
jQuery.each(selector.split(/\,/), function() {
var out2 = [];
jQuery.each(self.cleanCss(this).split(/\s+/), function() {
out2.push(self.tokenizeCss(this));
});
out.push(out2);
});
return out;
};
// Everything in the first selector must be present in the second.
DomPredictionHelper.prototype.selectorBlockMatchesSelectorBlock = function(selector_block1, selector_block2) {
for (var j = 0; j < selector_block1.length; j++) {
if (jQuery.inArray(selector_block1[j], selector_block2) == -1) {
return false;
}
}
return true;
};
// Assumes list is an array of complete CSS selectors represented as strings.
DomPredictionHelper.prototype.selectorGets = function(type, list, the_selector) {
var self = this;
var result = true;
if (list.length == 0 && type == 'all') return false;
if (list.length == 0 && type == 'none') return true;
var selectors = self.fragmentSelector(the_selector);
var cleaned_list = [];
jQuery.each(list, function() {
cleaned_list.push(self.fragmentSelector(this)[0]);
});
jQuery.each(selectors, function() {
if (!result) return;
var selector = this;
jQuery.each(cleaned_list, function(pos) {
if (!result || this == '') return;
if (self._selectorGets(this, selector)) {
if (type == 'none') result = false;
cleaned_list[pos] = '';
}
});
});
if (type == 'all' && cleaned_list.join('').length > 0) { // Some candidates didn't get matched.
result = false;
}
return result;
};
DomPredictionHelper.prototype._selectorGets = function(candidate_as_blocks, selector_as_blocks) {
var cannot_match = false;
var position = candidate_as_blocks.length - 1;
for (var i = selector_as_blocks.length - 1; i > -1; i--) {
if (cannot_match) break;
if (i == selector_as_blocks.length - 1) { // First element on right.
// If we don't match the first element, we cannot match.
if (!this.selectorBlockMatchesSelectorBlock(selector_as_blocks[i], candidate_as_blocks[position])) cannot_match = true;
position--;
} else {
var found = false;
while (position > -1 && !found) {
found = this.selectorBlockMatchesSelectorBlock(selector_as_blocks[i], candidate_as_blocks[position]);
position--;
}
if (!found) cannot_match = true;
}
}
return !cannot_match;
};
DomPredictionHelper.prototype.invertObject = function(object) {
var new_object = {};
jQuery.each(object, function(key, value) {
new_object[value] = key;
});
return new_object;
};
DomPredictionHelper.prototype.cssToXPath = function(css_string) {
var tokens = this.tokenizeCss(css_string);
if (tokens[0] && tokens[0] == ' ') tokens.splice(0, 1);
if (tokens[tokens.length - 1] && tokens[tokens.length - 1] == ' ') tokens.splice(tokens.length - 1, 1);
var css_block = [];
var out = "";
for(var i = 0; i < tokens.length; i++) {
if (tokens[i] == ' ') {
out += this.cssToXPathBlockHelper(css_block);
css_block = [];
} else {
css_block.push(tokens[i]);
}
}
return out + this.cssToXPathBlockHelper(css_block);
};
// Process a block (html entity, class(es), id, :nth-child()) of css
DomPredictionHelper.prototype.cssToXPathBlockHelper = function(css_block) {
if (css_block.length == 0) return '//';
var out = '//';
var first = css_block[0].substring(0,1);
if (first == ',') return " | ";
if (jQuery.inArray(first, [':', '#', '.']) != -1) {
out += '*';
}
var expressions = [];
var re = null;
for(var i = 0; i < css_block.length; i++) {
var current = css_block[i];
first = current.substring(0,1);
var rest = current.substring(1);
if (first == ':') {
// We only support :nth-child(n) at the moment.
if (re = rest.match(/^nth-child\((\d+)\)$/))
expressions.push('(((count(preceding-sibling::*) + 1) = ' + re[1] + ') and parent::*)');
} else if (first == '.') {
expressions.push('contains(concat( " ", #class, " " ), concat( " ", "' + rest + '", " " ))');
} else if (first == '#') {
expressions.push('(#id = "' + rest + '")');
} else if (first == ',') {
} else {
out += current;
}
}
if (expressions.length > 0) out += '[';
for (var i = 0; i < expressions.length; i++) {
out += expressions[i];
if (i < expressions.length - 1) out += ' and ';
}
if (expressions.length > 0) out += ']';
return out;
};

How to implement lambda /anonymous functions in JavaScript

So I am trying to implement a subset of LISP using JavaScript. I am stuck on two things related to lambdas.
How to implement the ability to create a lambda and at the same time feed it the arguments and have it immediately evaluated? For example:
((lambda(x)(* x 2)) 3)
For now I hard-coded this functionality in my eval-loop like this:
else if (isArray(expr)){
if (expr[0][0] === 'lambda' || expr[0][0] === 'string') {
console.log("This is a special lambda");
var lambdaFunc = evaluate(expr[0], env)
var lambdaArgs = [];
for(var i = 1; i < expr.length; i++){
lambdaArgs.push(expr[i]);
}
return lambdaFunc.apply(this, lambdaArgs);
}
Now this works, and if I write the above lambda with the parameter it will evaluate to 6, however, I am wondering if there is any smarter way to implement this?
If a lambda is instead bound to a symbol, for example:
(define fib (lambda(n)
(if (< n 2) 1
(+ (fib (- n 1))(fib (- n 2)))
)))
In this case, the (define fib) part will be evaluated by the eval-loop first, just as if fib was simply being assigned a number:
else if (expr[0] === 'define') { // (define var value)
console.log(expr + " is a define statement");
var newVar = expr[1];
var newVal = evaluate(expr[2], env);
env.add(newVar, newVal);
return env;
}
And the lambda-function is being created like this:
else if (expr[0] === 'lambda') { // (lambda args body)
console.log(expr + " is a lambda statement");
var args = expr[1];
var body = expr[2];
return createLambda(args, body, env);
}
Separate function to create the lambda:
function createLambda(args, body, env){ // lambda args body
function runLambda(){
var lambdaEnvironment = new environment(env, "lambda environment");
for (var i = 0; i < arguments.length; i++){
lambdaEnvironment.add(args[i], evaluate(arguments[i], env));
}
return evaluate(body, lambdaEnvironment);
}
return runLambda;
}
This works fine for lambdas such as:
(define range (lambda (a b)
(if (= a b) (quote ())
(cons a (range (+ a 1) b)))))
(define fact (lambda (n)
(if (<= n 1) 1
(* n (fact (- n 1))))))
For example, (range 0 10) returns a list from 0 to 10.
But if I try a lambda within a lambda, it does not work. For example:
(define twice (lambda (x) (* 2 x)))
(define repeat (lambda (f) (lambda (x) (f (f x)))))
I would expect the following to return 40:
((repeat twice) 10)
But instead, it returns a list looking like this:
function runLambda(){ var lambdaEnvironment = new environment(env, "lambda
environment"); for (var i = 0; i < arguments.length; i++){
lambdaEnvironment.add(args[i], evaluate(arguments[i], env)); } return
evaluate(body, lambdaEnvironment); },10
Any ideas what might be missing here?
Full JavaScript;
//functions for parsing invoice String
function parse(exp) {
return readFromTokes(tokenize(exp));//code
}
function isNumeric(arg){
return !isNaN(arg);
}
function isArray(obj){
return !!obj && obj.constructor === Array;
}
function readFromTokes(exp){
//Create abstract syntax tree
if (exp.length == 0) {
}
var token = exp.shift();
if (token == '('){
var L = [];
while (exp[0] != ')') {
L.push(readFromTokes(exp));
}
exp.shift(); //remove end paranthesis
return L;
} else {
if (token == ')') {
console.log("Unexpected )");
} else {
return atom(token);
}
}
}
function tokenize(exp){
//Convert a program in form of a string into an array (list)
var re = /\(/g;
var re2 = /\)/g;
exp = exp.replace(re, " ( ");
exp = exp.replace(re2, " ) ");
exp = exp.replace(/\s+/g, ' ');
exp = exp.trim().split(" ");
return exp;
}
function atom(exp){
if (isNumeric(exp)) {
return parseInt(exp); //A number is a number
} else {
return exp; //Everything else is a symbol
}
}
function environment(parentEnvironment, name){
var bindings = [];
var parent = parentEnvironment;
var name = name;
function add(variable, value){
console.log("variable: " + variable + " value: " + value);
bindings.push([variable, value]);
}
function printName(){
console.log(name);
}
function print() {
console.log("printing environment: ")
for (var i = 0; i < bindings.length; i++){
console.log(bindings[i][0] + " " + bindings[i][1]);
}
}
function get(variable){
for (var i = 0; i < bindings.length; i++){
if (variable == bindings[i][0]){
return bindings[i][1];
}
}
if (parent != null){
return parent.get(variable);
} else {
console.log("No such variable");
return false;
}
}
function getParent(){
return parent;
}
this.add = add;
this.get = get;
this.getParent = getParent;
this.print = print;
this.printName = printName;
return this;
}
function addPrimitives(env){
env.add("+", function() {var s = 0; for (var i = 0; i<arguments.length;i++){ s += arguments[i];} return s});
env.add("-", function() {var s = arguments[0]; for (var i = 1; i<arguments.length;i++){ s -= arguments[i];} return s});
env.add("*", function() {var s = 1; for (var i = 0; i<arguments.length;i++){ s *= arguments[i];} return s});
env.add("/", function(x, y) { return x / y });
env.add("false", false);
env.add("true", true);
env.add(">", function(x, y){ return (x > y) });
env.add("<", function(x, y){ return (x < y) });
env.add("=", function(x, y){ return (x === y)});
env.add(">=", function(x, y){ if (x >= y){return true;} else {return false;}});
env.add("<=", function(x, y){ if (x <= y){return true;} else {return false;}});
env.add("eq?", function() {var s = arguments[0]; var t = true; for(var i = 1; i<arguments.length; i++){ if (arguments[i] != s) {t = false }} return t;});
env.add("cons", function(x, y) { var temp = [x]; return temp.concat(y); });
env.add("car", function(x) { return x[0]; });
env.add("cdr", function(x) { return x.slice(1); });
env.add("list", function () { return Array.prototype.slice.call(arguments); });
env.add("list?", function(x) {return isArray(x); });
env.add("null", null);
env.add("null?", function (x) { return (!x || x.length === 0); });
}
function createLambda(args, body, env){ // lambda args body
function runLambda(){
var lambdaEnvironment = new environment(env, "lambda environment");
for (var i = 0; i < arguments.length; i++){
lambdaEnvironment.add(args[i], evaluate(arguments[i], env));
}
return evaluate(body, lambdaEnvironment);
}
return runLambda;
}
function evaluate(expr, env) {
console.log(expr + " has entered evaluate loop");
if (typeof expr === 'string') {
console.log(expr + " is a symbol");
return env.get(expr);
} else if (typeof expr === 'number') {
console.log(expr + " is a number");
return expr;
} else if (expr[0] === 'define') { // (define var value)
console.log(expr + " is a define statement");
var newVar = expr[1];
var newVal = evaluate(expr[2], env);
env.add(newVar, newVal);
return env;
} else if (expr[0] === 'lambda') { // (lambda args body)
console.log(expr + " is a lambda statement");
var args = expr[1];
var body = expr[2];
return createLambda(args, body, env);
} else if (expr[0] === 'quote') {
return expr[1];
} else if (expr[0] === 'cond'){
console.log(expr + " is a conditional");
for (var i = 1; i < expr.length; i++){
var temp = expr[i];
if (evaluate(temp[0], env)) {
console.log(temp[0] + " is evaluated as true");
return evaluate(temp[1], env);
}
}
console.log("no case was evaluated as true");
return;
} else if (expr[0] === 'if') {
console.log(expr + "is an if case");
return function(test, caseyes, caseno, env){
if (test) {
return evaluate(caseyes, env);
} else {
return evaluate(caseno, env);
}
}(evaluate(expr[1], env), expr[2], expr[3], env);
} else if (typeof expr[0] === 'string'){
console.log(expr + " is a function call");
var lispFunc = env.get(expr[0]);
var lispFuncArgs = [];
for(var i = 1; i < expr.length; i++){
lispFuncArgs.push(evaluate(expr[i], env));
}
return lispFunc.apply(this, lispFuncArgs);
} else if (isArray(expr)){
if (expr[0][0] === 'lambda' || expr[0][0] === 'string') {
console.log("This is a special lambda");
var lambdaFunc = evaluate(expr[0], env)
var lambdaArgs= [];
for(var i = 1; i < expr.length; i++){
lambdaArgs.push(expr[i]);
}
return lambdaFunc.apply(this, lambdaArgs);
} else {
console.log(expr + " is a list");
var evaluatedList = [];
for(var i = 0; i < expr.length; i++){
evaluatedList.push(evaluate(expr[i], env));
}
return evaluatedList;
}
} else {
console.log(expr + " cannot be interpreted");
}
}
var globalEnvironment = new environment(null, "Global");
addPrimitives(globalEnvironment);
function start(string) {
return evaluate(parse(string), globalEnvironment);
}
var output = function (string) {
try {
document.getElementById('debugdiv').innerHTML = start(string);
} catch (e) {
document.getElementById('debugdiv').innerHTML = e.name + ': ' + e.message;
}
};
Full HTML;
<html>
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Script-Type" content="text/javascript">
<title>LISP in JavaScript</title>
<script type="text/javascript" src="lisp.js"></script>
</head>
<body>
<form id="repl" name="repl" action="parse(prompt.value)">
lisp==>
<input id="prompt" size="200" value="" name="prompt" maxlength="512">
<br>
<input type=button style="width:60px;height:30px" name="btnEval" value="eval" onclick="output(prompt.value)">
<br>
</form>
<div id="debugdiv" style="background-color:orange;width=100px;height=20px">
</div>
</body>
</html>
Further thoughts, suggestions and comments are of course also welcome.
Thank you!

You don't inspect the structure of the operand to see if it's a lambda you eval the operand. The standard way of eval is to check if it's primitive type, then check for special forms and macros, then eval the operator and operands before applying.
Just remove the part where expr[0][0] === 'lambda' || expr[0][0] === 'string' is true and instead of just returning the evaluation of the form you need to apply the operand:
else if (isArray(expr)){
const fn = evaluate(expr[0], env);
const evaluatedList = [];
for(var i = 1; i < expr.length; i++){
evaluatedList.push(evaluate(expr[i], env));
}
return fn(...evaluatedList);
}
The createLambda is wrong since you are evaluating the arguments in the wrong environment. This would be correct since the arguments are already evaluated:
function createLambda(args, body, env){ // lambda args body
function runLambda(){
const lambdaEnvironment = new environment(env, "lambda environment");
for (let i = 0; i < arguments.length; i++){
lambdaEnvironment.add(args[i], arguments[i]);
}
return evaluate(body, lambdaEnvironment);
}
return runLambda;
}

Search, count duplicated strings and add for each numbers

I have a script that is searching for duplicated text strings in an array and changing the colors.
function checkDuplicates() {
var values = new Array();
var $input = $('input[type=\'text\']');
var error = 0;
$input.each(function() {
$(this).removeClass('double-error');
var that = this;
if (that.value!='') {
values[that.value] = 0;
$('input[type=\'text\']').each(function() {
if (this.value == that.value) {
values[that.value]++;
}
});
} //endif
});
$input.each(function(key) {
if (values[this.value]>1) {
error++;
$(this).addClass('double-error');
}
});
return (error <= 0); //returns false or true
}
<style type="text/css">
.double-error {
color:red;
border:1px solid red;
}
</style>
This is working fine.
However, I need to count duplicated strings and add keep track of whether they are the first occurence of that word, the second occurence of that word, etc.
For example:
Given john, john, peter, doe, peter, john, the result would be john-1, john-2, peter-1, doe, peter-2, john-3.
This is what I currently have:
function eliminateDuplicates() {
var values = new Array();
var $input = $('input[type=\'text\']');
var error = 0;
$input.each(function() {
$(this).removeClass('double-error');
var that = this;
if (that.value!='') {
values[that.value] = 0;
$('input[type=\'text\']').each(function() {
if (this.value == that.value) {
values[that.value]++;
}
});
}
});
$input.each(function(key) {
if (values[this.value]>1) {
error++;
myArray = values[this.value];
for (var i = 0; i < myArray; i++) {
$(this).parent()
.find('input[type=\'text\']')
.val(this.value + '-' + i);
}
}
});
return error <= 0; //return error > 0 ? false : true;
}
But I got this result:
john-0-1-2, john-0-1-2, peter-0-1, doe, peter-0-1, john-0-1-2
What's wrong?
I make some modification:
function eliminateDuplicates() {
var values = new Array();
var $input = $('input[type=\'text\']');
var error = 0;
$input.each(function() {
$(this).removeClass('double-error');
var that = this;
if (that.value!='') {
values[that.value] = 0;
$('input[type=\'text\']').each(function() {
if (this.value == that.value) {
values[that.value]++;
}
});
}
});
$input.each(function(key) {
if (values[this.value]>1) {
var name=this.value;
var names = values[this.value];
values[this.value]++;
for (var i = 0; i < names; i++){
$(this).parent().find('input[type=\'text\']').val(name + '-' + i);
}
}
});
checkDoubles();
return error <= 0; //return error > 0 ? false : true;
}
now I getting counts in sequence but not from 1.
for example if I have 4 duplicated names (Peter) i getting:
Peter-3, Peter-4, Peter-5, Peter-6.
but I need
Peter-1, Peter-2, Peter-3, Peter-4.
what wrong?

I think you're looking for something like this:
function eliminateDuplicates() {
var repeats = {};
var error = false;
//cache inputs
var $inputs = $("input[type='text']");
//loop through inputs and update repeats
for (i = 0; i < $inputs.length; ++i) {
//cache current element
var cur = $inputs[i];
//remove class
$(cur).removeClass("double-error");
//get text of this element
var text = $(cur).val();
//no text -- continue
if (text === "") {
continue;
}
//first time we've came across this value -- intialize it's counter to 1
if ((text in repeats) === false) {
repeats[text] = 1;
}
//repeat offender. Increment its counter.
else {
repeats[text] = repeats[text] + 1;
}
//update the the value for this one
$(cur).val(text + "-" + repeats[text]);
}
return error; // always returns false since I'm not sure
// when it's supposed to return true.
}
PS: I didn't understand when error was supposed to be true, so it's always false. Nevertheless, this should be enough to get you going.
PPS: Plunker here.

Get only the specified styles of an element :)

I can get a style of an element just doing this:
alert (document.defaultView.getComputedStyle (document.getElementById ("element"), null).getPropertyValue ("background-color"));
I can get all styles of an element just doing this:
var styles = document.defaultView.getComputedStyle (document.getElementById ("element"), null);
var string = ""
for (var i = 0; i < styles.length; i ++) {
string = string + styles[i] + ": " + styles.getPropertyValue (styles[i]) + "\n";
}
alert (string);
But, how can I get only the specified styles of an element?

What do you mean by 'specified styles'? Do you mean:
var el = document.getElementById("element");
alert(el.style.display);
alert(el.style.background);
...etc...
or do you mean something like this:
function in_array (needle, haystack, argStrict) {
var key = '', strict = !!argStrict;
if (strict) {
for (key in haystack) {
if (haystack[key] === needle) {
return true;
}
}
} else {
for (key in haystack) {
if (haystack[key] == needle) {
return true;
}
}
}
return false;
}
var styles = document.defaultView.getComputedStyle (document.getElementById ("element"), null);
var string = "";
var whichStyles = ['display','background-color'];
for (var i = 0; i < styles.length; i ++) {
if(in_array(styles[i], whichStyles) {
string = string + styles[i] + ": " + styles.getPropertyValue (styles[i]) + "\n";
}
}
alert (string);