PawvaScript

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Introduction

Ever wish that JavaScript had fewer symbols and more dogs? We did, so we made PawvaScript!

PawvaScript is an object-oriented scripting language designed to make JavaScript more programmer-friendly (so friendly that your dog could learn it, probably). PawvaScript draws on many fundamentals from JavaScript but replaces confusing symbols with clear and (dog-friendly) readable terms, adds types (like TypeScript) to help with debugging, and throws in some paw-sitively awesome dog-related keywords just for fun and tail wags.

Check out the full Ohm description of the PawvaScript grammar here!

Features

• Language for scripting
• Object-Oriented
  • breeds are what we call classes!
• Static typing
• Functions
  • we call them tricks!
• 5 basic types
  • leash (string)
  • goodBoy (boolean)
  • toeBeans (number)
  • pack (list)
  • kennel (map)
• 5 kinds of loops
  • Forever
  • Fixed
  • While
  • For
  • ForEach
• Conditional Statements
• Spread/peanutButter syntax
• Single and multi-line comments

Example Programs

Hello, World!

Let's start with a classic.

PawvaScript	JavaScript
woof "Hello, World!"; bark "my ball!"; howl "uh-oh";	console.log("Hello, World!";) console.log("my ball!".toUpperCase()); console.error("uh-oh");

Types

PawvaScript's primitive types are similar to JavaScripts, and it also has data structures like Python's lists and dictionaries.

PawvaScript	Javascript/Python
goodBoy	boolean
leash	string
toeBeans	number
trick	function
pack	array/list
kennel	map/dictionary
breed	class/object

Variable Declaration and Assignment

Variables are declared with their type.

PawvaScript	JavaScript
leash dogName is "CeCe"; toeBeans dogAge is 12; goodBoy isGoodBoy is good; goodBoy isNaughtyDoggo is bad;	let dogName = "CeCe"; let dogAge = 12; let isGoodBoy = true; let isNaughtyDoggo = false;
pack[leash] dogNames is ["CeCe", "Fluffy"]; kennel[leash:toeBeans] dogAges is ["CeCe": 1, "Fluffy": 2];	let dogNames = ["CeCe", "Fluffy"]; let dogAges = {"CeCe": 1, "Fluffy": 2};
toeBeans cuteness; !!! Default value is 0 !!! cuteness is 100;	let cuteness = 0; cuteness = 100;
!!! cat is the equivalent of null. !!! !!! Any type can have the value cat !!! leash theBestestDog is cat;	let theBestestDog = null;

Leashes/Strings

PawvaScript supports leash interpolation and concetation:

PawvaScript	JavaScript
leash dogName is "Ce" with "Ce"; leash sentence is "![dogName] is the best dog";	let dogName = "Ce" + "Ce"; let sentence = `${dogName} is the best dog";

Packs/Lists

Packs are the PawvaScript equivalent of lists in Python or arrays in JavaScript:

PawvaScript	JavaScript
pack[leash] goodDogs is ["CeCe", "Buster", "Muffin"]; pack[toeBeans] ages is [1, 1, 2];	let goodDogs = ["CeCe", "Buster", "Muffin"]; let ages = [1, 1, 2];
!!! "without" removes elements from a pack !!! pack[leash] bestDogs is goodDogs without "Muffin";	let bestDogs = goodDogs.filter(dogName => dogName != "Muffin");
!!! "peanutButter" is the spread operator !!! pack[leash] smallDogs is ["Tiny", "Teenie", "Boo"]; pack[leash] bigDogs is ["Boofer", "Woofer," "Mo"]; pack[leash] allDogs is [ peanutButter smallDogs, peanutButter bigDogs ]; woof allDogs; !!! ["Tiny", "Teenie", "Boo", "Boofer", "Woofer", "Mo"] !!!	let smallDogs = ["Tiny", "Teenie", "Boo"]; let bigDogs = ["Boofer", "Woofer", "Mo"]; let allDogs = [ ...smallDogs, ...bigDogs ];

Kennels/Maps

Kennels are data structures like Python dictionaries.

PawvaScript	JavaScript
kennel[leash:leash] goodDogs is [ "CeCe": "German Shepherd", "Buster": "Golden Doodle", "Mo": "Potato" ]; kennel[leash:toeBeans] ages is ["CeCe": 1, "Buster": 1, "Mo": 5];	let goodDogs = { "CeCe": "German Shepherd", "Buster": "Golden Doodle", "Mo": "Potato" }; let ages = {CeCe: 1, Buster: 1, Mo: 5};

Relational Operators

Wanna compare stuff?

PawvaScript	JavaScript
goodBoy a is x equals y; a is x notEquals y; a is x isGreaterThan y; a is x isLessThan y; a is x isAtLeast y; a is x isAtMost y;	let a = x === y; a = x !== y; let a = x > y; a = x < y; let a = x >= y; a = x <= y;

Arithmetic Operators

PawvaScript	JavaScript
toeBeans a is x + y; a is x - y; a is x * y; a is x / y; a is x mod y; a is x!; a is -x;	a = x + y; a = x - y; a = x * y; a = x / y; a = x % y; a = x!; a = -x;

Conditional Statements

PawvaScript	JavaScript
if x isAtLeast y then: leash dogName is "CeCe"; else: leash dogName is "Buster"; tail	if (x <= y) { let dogName = "CeCe"; else { let dogName = "Buster"; }
if x notEquals y then: woof "CeCe is kinda cute"; else if x isGreaterThan y then: woof "CeCe is pretty cute"; else if x isLessThan y then: woof "Okay, CeCe is really cute"; else: woof "CeCe is the cutest of the cutest";	if (x !== y) { console.log("CeCe is kinda cute"); else if (x > y) { console.log("CeCe is pretty cute"); else if (x < y) { console.log("Okay, CeCe is really cute"); else { console.log("CeCe is the cutest of the cutest"); }

Comments

Let's write some comments!

PawvaScript	JavaScript
!!! I'm a one line comment !!! !!! I'm a multiline comment !!!	// I'm a comment /* I'm a multiline comment */

Loops

Forever Loop

PawvaScript	JavaScript
chase: woof "I run forever!"; tail	while (true) { console.log("I run forever\!"); }

Fixed Loop

PawvaScript	JavaScript
chase 5 times: woof "Stay."; tail	for (let i = 0; i < 5; i++) { console.log("Stay."); }

While Loop

PawvaScript	JavaScript
chase while x isAtMost 5: woof x; tail	while (x <= 5) { console.log(x); }

For Loop

PawvaScript	JavaScript
chase toeBeans i is 0 by i*2 while i isLessThan 10: woof i; tail	for (let i = 0; i < 10; i *= 2) { console.log(i); }

For Each Loop

PawvaScript	JavaScript
chase element through myPack: woof element; tail	for (let element of myArray) { console.log(element); }

Use poop and walkies to break and continue, respectively.

PawvaScript	JavaScript
chase element through myPack: if element equals cat then: poop; else if element equals "CeCe" then: walkies; tail; woof element; tail	for (let element of myArray) { if (element === null) { break; } else if (element === "CeCe") { continue; } console.log(element); }

Tricks

Let's find the greatest common divisor between two toeBeans!

PawvaScript	JavaScript
trick gcd chews[toeBeans:num1, toeBeans:num2] fetches toeBeans: toeBeans remainder; chase while (a mod b) isGreaterThan 0: remainder is (a mod b); a is b; b is remainder; tail; give a; tail	function gcd(num1, num2) { let remainder; while ((num1 % num2) > 0) { remainder = a % b; a = b; b = remainder; } return a; }
toeBeans a is 8; toeBeans b is 12; toeBeans c is gcd(a, b);	let a = 8; let b = 12; let c = gcd(a, b);

The classic Fibonacci function to get the nth term of the Fibonacci sequence:

PawvaScript	JavaScript
trick fib chews[toeBeans:n] fetches toeBeans: if n isAtMost 1 then: give n; else: give fib(n-1) + fib(n-2); tail tail	function fib(n) { if (n <=1) { return n; } else { return fib(n-1) + fib(n-2); } }
toeBeans huzzah is fib(100);	let huzzah = fib(100);

Breeds

Let's make an owner breed!

PawvaScript	JavaScript
breed Owner is: leash dogName; trick Owner chews[leash:dogName] fetches Owner; trick introduceDog: woof "My dog's name is " with Owner's dogName; tail trick command fetches leash: give Owner's dogName with ", stay!"; tail tail Owner lucille is Owner("CeCe") (lucille's introduceDog)() !!! output: "My dog's name is CeCe" !!! woof lucille's command() !!! output: "CeCe, stay." !!!	class Owner { constructor(dogName) { this.dogName = dogName; } introduceDog() { console.log(`My dog's name is ${this.dogName}`; } command() { return `${this.dogName}, stay!`; } } let lucille = new Owner("CeCe"); lucille.introduceDog(); console.log(lucille.command());

Bad Boys: Semantic Errors

• The target and source of a variable declaration must have the same type.
• The target and source of an assignment statement must have the same type.
• Types and functions cannot be declared in loops.
• Variables can only be declared once in the same block.
• Conditions in if statements must be booleans.
• Conditions in loops must be booleans.
• For loop variables must evaluate to a number.
• Through loops can only be used on lists. (We hope to expand this functionality to other types soon!)
• A through loop's variable cannot be changed in the body of the loop (read-only).
• Types can only have one constructor.
• A constructor's identifier must match the identifier of the type it constructs.
• The parameters of a constructor must be fields in their type.
• A constructor can only return the breedType it is a part of.
• If a function's signature contains a return type, the function must and can only return an object of the return type.
• Functions must be called with the same number of arguments as described in the function signature.
• Each function argument must be the same type as argument in that same positiion in the function signature.
• Spreads can only be used on list members that are also lists, and the member types of the lists must be the same.
• A dictionary's keys must all have the same type and its values must also all be of the same type.
• The unary operators "-" and "!" can only be used with numbers.
• The operator "not" can only be used with booleans.
• The binary operators "-", "+", "*", and "/" can only be used with numbers on either side.
• The operators "&" and "|" can only be used with booleans on either side.
• The operators "isGreaterThan", "isAtLeast", "isAtMost", "isLessThan", "equals", and "notEquals" can only be used with numbers and strings and the types must match on both sides.
• The operators "with" and "without" can only be used with strings and lists and the types must match on both sides.
• The "at" operator can only be used with a list on the left and numbers on the right.
• The "of" operator can only be used with a dictionary on the left and numbers on the right and the key used must match the type of the keys in the dictionary.
• Give statements can only be used in functions, methods, and loops.
• Break and continue statements can only be used in loops.

Happy PawvaScript coding! Remember: Good Dogs only!