• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
Ectara

Lexical Parsing With Meaningful Errors

4 posts in this topic

I have a lexical parser that I'm writing that parses as it reads the input with a shift and reduce parser that accumulates lexemes until it can determine that there is syntactic meaning to the topmost tokens on the stack, then it groups them as children to a node of the non-terminal's type, then pushes the new node. At the end of parsing, it results in an abstract syntax tree; however, if there is an error in parsing and it is malformed, I have the feeling that the tree will be incorrectly generated, with error information being difficult to recover. The tree generation uses the lexer's underlying internal functions for handling the input text, and returning the next lexeme. If the input is perfectly formed, it would result in a correct tree, without any line numbers or information associated with the input text. Is there a better way to parse the files that would preserve the information? With slight modification, I suppose I could track column and line numbers.
0

Share this post


Link to post
Share on other sites
[quote name='Ectara' timestamp='1343246150' post='4963047']
At the end of parsing, it results in an abstract syntax tree; however, if there is an error in parsing and it is malformed, I have the feeling that the tree will be incorrectly generated, with error information being difficult to recover.
[/quote]

If there is an error in parsing, you should never reach the end. You should error with 'expected X saw ___' if possible. Otherwise, keeping track of the 'deepest' attempted parse is usually sufficient to identify where things went south. If your parsing has a bug on the otherhand... [i]shrug[/i].

From experience, it is important to carry enough information to provide a filename (or other source identification string) [i]and [/i]a line/column number - [b]all the way through to code generation. [/b]Not only does it make things easier to debug, but you need to eventually output debugging symbols, which use this info so your output itself is debuggable.
0

Share this post


Link to post
Share on other sites
Right, I understand this. Is there a better way to parse the files that would preserve the information? I could get the lexemes one by one, and keep track of it easily. However, parsing from top to bottom seems silly, when parsing from bottom to top makes the most sense. However, parsing from the bottom up cannot see the big picture, and thus when an error occurs, you wouldn't quite know it for a while, and even then, it is hard to know what was really expected. The method I have would work, but it is the unexpected error that would break its behavior.
0

Share this post


Link to post
Share on other sites
I would suggest having a look at how Clang does its error handling, cause not only does it have the most informative errors and warnings I've ever seen, its doing it for some of the most complex programming languages available (in terms of processing), plus it runs very efficiently (both speed and memory wise).
0

Share this post


Link to post
Share on other sites
I'm reading through all of its source, but it is extremely difficult to digest, especially with just about all of the code written in its headers. Does this mean I'm on the right track with a LALR parser using a shift-and-reduce method?
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0