YentaA Simple Recommendation Language

Kenny Rivera - TesterBecky Tang – System Architect

Shylah Weber – Systems IntegratorAnthony Yim – Project Manager

Definition

Yenta1) Yiddish word which describes an old woman who is a matchmaker - a Yentle. (Ref. Fiddler on the Roof) 2) In modern use the meaning has become that of an annoying old hag.

(http://www.urbandictionary.com)

Motivation

Recommendation engines are becoming increasingly popular

We wanted to make recommendations:• Fast

• Simple to program

• Flexible in content

Overview

Imperative language

Yenta allows recommendations based on either of the following input:

• A “seed” or example piece of data• A set of criteria or “tags”

Title Artist Album Year Genre Length

Wrapped George Strait It Just Comes Natural 2006 Country 4:10

You Got Lucky Tom Petty Greatest Hits 2000 Rock 3:36

MMMBop Hanson Middle of Nowhere 1997 Pop 4:29

Syntactic Constructs

• Sample Yenta program:

• Built-in subroutines (3 main steps)– import(string fileName)– applyBasicScore(string tag, string tagValue, double weight, . . . )– printTop(int n)

• Java-like declarations of primitive types– file type

file myMusicFile = import("music.txt");myMusicFile.applyScore("Year", ”2006", "0.8", "Genre", "Pop", "0.2");myMusicFile.printTop(3);

public void importFile(String filename)throws IOException{BufferedReader in = new BufferedReader(new FileReader(filename)); BufferedReader in2 = new BufferedReader(new FileReader(filename));

String line = in.readLine();String lineCopy = line; rows = 0;while (line != null){

rows++;line = in.readLine();

}StringTokenizer st = new StringTokenizer(lineCopy, ”\t");cols = 0;while(st.hasMoreTokens()){

st.nextToken();cols++;

}tags = new Tag[cols]; line = in2.readLine();StringTokenizer st3 = new StringTokenizer(line, ”\t");for(int k = 0; (k < cols) && st3.hasMoreTokens(); k++){ tags[k] = new Tag(st3.nextToken());

tags[k].col = k;}rows--;file = new String[rows][cols];line = in2.readLine();int i = 0;while (line != null){

StringTokenizer st2 = new StringTokenizer(line, ”\t");int j = 0;while(st2.hasMoreTokens()){

file[i][j] = st2.nextToken();j++;

}i++;line = in2.readLine();

}scores = new double[rows];

}

Equivalent Java Code for Import()

Yikes!

Other Syntactic Constructs

• Flow control– for loops– if statements

• Other types– int– double– string (seen)– scoreFunc

Translator Architecture

Java compiler

Java file representing the Yenta program

Main.java

Yenta Output

Java program

Yenta Program

Main

Java compiler

Java interpreter

Java interpreter

Translator Architecture

Java compiler

YentaProg.java

Main.java

Yenta Output

YentaProg

YentaProg.txt

Main

Java compiler

Java interpreter

Java interpreter

javac Main.javajava Main < YentaProg.txtjavac YentaProg.javajava YentaProg

Interpreter Implementation

• Wrote Java methods that are always in the output file

• Our grammar simply calls these methods with the programmer’s parameters

Development Environment

+ +

+

Tools

ANTLR v3• Parser + Lexer• Takes a LL(*) grammar as input.• “Spits out” tokens as output.

Example ANTLR grammar

Tools

ANTLRWorks parse tree

Tools

StringTemplateexample StringTemplate

Equiv. Java code that was “printed” out.

Outputs…

The Proposed Test Suite

• Unit testing– Grammar was constructed based on several

programs designed to exploit key features– Advantages:• Provides strict guidelines that code must satisfy.• Unit testing finds problems early in development

• Fuzz testing– Provides random data to our example programs to

test for errors and inconsistencies

Advantages

Yenta is a simple, easy-to-use language that is:

• Easy to learn

• Fast to write

• Concise, easy-to-read code

• Can be used by beginners but also augmented by more advanced features

Advantages

Yenta’s primary advantage is that it can be used to recommend anything a programmer wishes

(Like Columbia classes!)