It means that a program could be designed to read, generate, analyse or transform other programs, and even modify itself while running. Once the domain of expert rubyists, metaprogramming is now accessible to. Metaprogramming ruby, second edition makes mastering the language enjoyable. Ruby metaprogramming study note try to hack the sample apps. In early 2002, the englishlanguage ruby talk mailing list was receiving more messages than the japaneselanguage ruby list, demonstrating ruby s increasing popularity in the nonjapanese speaking world. This pdf file contains pages extracted from metaprogramming ruby 2, published by the pragmatic. It provides programmatic access to the contents of a pdf file with a high degree of flexibility. Program like the ruby pros kindle edition by perrotta, paolo.
Im also preparing you for metaprogramming, which, if you can smell that. This method executes a string as ruby code, within the context of a. To run this sample, get started with a free trial of pdftron sdk. Starting off the list for examples of metaprogramming is monkey patching. In this article, toptal engineer nikola todorovic demystifies. Collection of metaprogrammingrelated small snippets. When hes not writing code hes usually weightlifting. Presentation mode open print download current view. It is because of this very feature that many gems, such as rspec and activerecord, can work the way they do. Download it once and read it on your kindle device, pc, phones or tablets. In some cases, this allows programmers to minimize the number. In our journey through the world of test automation with ruby we have found that sometimes the data we need to validate is locked up in some. This pdf file contains pages extracted from metaprogramming ruby.
It means that a program can be designed to read, generate, analyze or transform other programs, and even modify itself while running. First, lets briefly address two methods that are key to performing our desired metaprogramming magic. Program like the ruby pros this pdf file contains pages extracted from metaprogramming ruby 2, published by the pragmatic bookshelf. Part i, metaprogramming ruby, is the core of the book. In part one we looked at what metaprogramming is and how it works. Pdf parser php library to parse pdf files and extract. Dig under the surface and explore ruby s most advanced feature. In this lecture, we will look at systems for building and testing your code, and for managing dependencies. This guest post is by gavin morrice, managing director of katana code ltd. I discovered most of this while building dwemthys array for my cartoon ruby book. Much of the worlds data are stored in portable document format pdf files.
Ruby s object model is the land in which metaprogramming. Programming challenges that let you experiment and play with some of the most outthere metaprogramming concepts. For more information or to purchase a paperback or. Pragmatic examples of metaprogramming in action, many of which come straight from reallife gems such as rails. Copyright c 20, decorators with args 47 from functools import wraps def debugprefix. This modified text is an extract of the original stack overflow documentation created by following contributors and released under cc bysa 3.
Understanding ruby metaprogramming and dsls dzone web dev. Pdfminer allows one to obtain the exact location of text in a. Sample ruby code for using pdftron sdk to read a pdf parse and extract text. Metaprogramming the missing semester of your cs education. Ruby everything is an object, including classes and methods everything inherits from the class object, including classes and methods. Metaprogramming is the writing of computer programs with the ability to treat programs as their data. Well, it was the best collective term we could come up with for the set of things that are more about process than they are about writing code or working more efficiently. Here are some of the things you can do with metaprogramming in the ruby language. Metaprogramming is a programming technique in which computer programs have the ability to treat other programs as their data. This is not my preferred storage or presentation format, so i often convert such files into databases, graphs, or spreadsheets.
I dynamic, interpreted high level language i has a rich, accessible runtime object model i depends on metaprogramming techniques usage of an object model. Although you have worded this carefully, i think you may be better off just going direct for a software recommendation question on the beta site softwarerecs. Sql falls under the category of external dsls, which means it requires its own parser and implementation of all of the necessary components. It comes down to the fact that all ruby code is executed codethere is no separate compile or runtime phase. An introduction to metaprogramming ryerson university. Origami is a pure ruby library to parse, modify and generate pdf documents. Yes, its a weird name, but its a powerful and dangerous tool. This is the secret to rails and ruby x11 and so many other examples of metaprogramming in ruby. Metaprogramming is the writing of computer programs that write or manipulate other programs or themselves as their data, or that do part of the work at compile time that would otherwise be done at runtime. After writing my last post on rails plugin idioms, i realized that ruby metaprogramming, at its core, is actually quite simple. As a ruby programmer, you already know how much fun it is. Metaprogramming ruby 2 program like the ruby pros by paolo perrotta. Unlike other pdf related tools, it focuses entirely on getting and analyzing text data.
The following chapters tell the story of a week in the life of a newly hired ruby programmer and his or her more experienced colleague. How to convert a pdf file to text and parse it in ruby. Generic pdf to text pdfminer pdfminer is a tool for extracting information from pdf documents. In this book, youll learn metaprogramming as an essential component of ruby and discover the deep, nonobvious details of. Say you want to write a ruby program that connects to an external systemmaybe a web service or a java program. Afterwards we will look at runtime metaprogramming in ruby in chapter vi and its rich runtime object model. I in most languages most information about structure is lost after compilation i the object model represents this structure at runtime. If youd like to search text on pdf pages, see our code sample for text search.
Write powerful ruby code that is easy to maintain and change. Php library to parse pdf files and extract elements like text. Ruby metaprogramming, one of the most interesting aspects of ruby, enables the programming language to achieve an extreme level of expressiveness. Program like the ruby pros by paolo perrotta free downlaod publisher. Use features like bookmarks, note taking and highlighting while reading metaprogramming ruby. Most interpreted languages have a way of parsing and executing arbitrary strings as code, but its usually regarded as a toy or a hazard, and not given much attention.
Metaprogramming with string evaluations reflection and. Compilers templating and generics refactoring tools. Metaprogramming ruby program like the ruby pros by paolo perrotta. The 3qi labs team decided there had to be a way to automate the extraction and parsing of these pdf s within our test automation scripts and the search began. Monkey patching is an object oriented programming technique that allows developers to. Parse the request variables and select the submitted username. In this lecture, we will look at systems for building and. With this knowledge we will look at the richest compiletime. What readers are saying about metaprogramming ruby. Ruby provides powerful reflection and metaprogramming facilities7 to obtain the runtime. You can write simple class methods which will add class methods to a derived class.
With metaprogramming, you can produce elegant, clean, and beautiful programs. Metaprogramming is writing code that manipulates language constructs e. Now see how to unleash its power, digging under the surface and exploring the languages most advanced features. Asking for best ruby library to parse pdfs and using the content from your. Metaprogramming ruby 2 program like the ruby pros paolo perrotta the pragmatic bookshelf dallas, texas raleigh, north carolina. The pdfreader library implements a pdf parser conforming as much as possible to the pdf specification from adobe. Modern programming languages provide extensive metaprogramming facilities.
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