Analyzing (un)structured data to convert it into a structured, normalized format.

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4
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2answers
607 views

Learning YACC nowadays, does it make sense? [closed]

I have a huge project that is using YACC and I would need to fix a bug in it. I might ask someone else who wrote that to fix it but I'm interested in how compilers work. Does it make sense to learn ...
4
votes
3answers
621 views

Any good reason to open files in text mode?

(Almost-)POSIX-compliant operating systems and Windows are known to distinguish between 'binary mode' and 'text mode' file I/O. While the former mode doesn't transform any data between the actual file ...
4
votes
1answer
274 views

How to line-break an email address?

After some discussion, I have come across a rather complicated situation. Say I intend to display an email address. I have, obviously, limited space available on the screen - be that browser or ...
4
votes
1answer
325 views

Object oriented parser model review

First time I make use of Code Review. At the moment I'm creating an Android application and the company I'm developing it for, has a specific file format that can be used to give text based data ...
4
votes
1answer
227 views

Is there such thing as an example driven parser generator or ad-hoc DSL development?

I'm intrested to know if there exists a tool that lets you input examples of valid documents and lets you then generalize from that to a reusable parser. I can imagine this, but everytime i start ...
4
votes
5answers
862 views

What would happen if you defined your system's CSV delimiter as being a quotation mark?

Title says it all. If the CSV's system delimiter was " (as opposed to a comma or pipe or other common alternatives), how would anything deal with it? The crux of the matter is of course that by ...
3
votes
3answers
647 views

How do I translate user input into a fictitious language?

For experimental reasons, I am trying to convert user input into a fictitious language. All of the translation can be 1:1. I would prefer if I could accomplish this with PHP. Should I use gettext ...
3
votes
3answers
918 views

How exactly is an Abstract Syntax Tree created?

I think I understand the goal of an AST, and I've built a couple of tree structures before, but never an AST. I'm mostly confused because the nodes are text and not number, so I can't think of a nice ...
3
votes
1answer
256 views

Showing a grammar is ambiguous

I have the following question taken from a compilers course exam: Show that the following grammar is ambiguous. S = XcY X = a Y = b | Z Z = bW W = d | ϵ I drew the following tree: Am I correct ...
3
votes
1answer
1k views

Any ASN.1 parsers written completely in managed code & safe from buffer overflows

ASN.1 is a data format used on HTTPS certificates, and various other critical pieces of infrastructure. I need to analyze some potentially hostile ASN.1 data, and want to ensure my code is safe from ...
3
votes
1answer
132 views

Recursively parse without resorting to ugly design patterns

I'm currently building a crochet pattern parser in Java, and I've hit upon some trouble. I'll call the language used for input Crochet Pattern Code (CPC). I have a rather large writeup on the ...
3
votes
2answers
130 views

Need overview of concepts and tools to translate a DSL to regular expressions

I'm looking for a little guidance. Until this morning, this was all over my head. After spending today researching Wikipedia, StackOverflow, etc., I'd say I've got my nose above the water. I'm tasked ...
3
votes
1answer
71 views

How to parse different number types with LALR(1)

Consider a LALR(1) parser for a file format that allows integer numbers and floating point numbers. As usual, something like 42 shall be a valid integer and a valid float (with some automagic ...
3
votes
1answer
204 views

Sentence Tree v/s Words List

I was recently tasked with building a Name Entity Recognizer as part of a project. The objective was to parse a given sentence and come up with all the possible combinations of the entities. One ...
3
votes
1answer
2k views

Extracting color profile information from JPEG files

I'm trying to look up info about reading JPEG's color profile info and to my surprise there's very little open specific how-to information on that regard, but rather lots of general explanation on ...
3
votes
2answers
119 views

Process to generate hierarchical structure based on relational data?

I have a csv of employee ids, names, and a reference column with the id of their direct manager, say something like this emp_id, emp_name, mgr_id 1,The Boss,, 2,Manager Joe,1 3,Manager Sally,1 ...
3
votes
1answer
297 views

Chosing a parser for a code beautifier

I'm in the planning stage of making a code beautifier (similar to AStyle or Uncrustify) - originally I was going to just contribute to one of those projects, but reviewing their source led me to the ...
3
votes
2answers
2k views

How to get lookahead symbol when constructing LR(1) NFA for parser?

I am reading an explanation (awesome "Parsing Techniques" by D.Grune and C.J.H.Jacobs; p.292 in the 2nd edition) about how to construct an LR(1) parser, and I am at the stage of building the initial ...
3
votes
3answers
501 views

design for a parser to handle very large files

I have written a program which records protocol messages between an application and a hardware device which matches each application request with each hardware response. This is so that I can later ...
3
votes
1answer
201 views

How to support mixed grammars?

I am currently writing a grammar for a programming language (PowerBuilder) and I am also collecting documentation about parsing and compilers creation. Now I would like to add in my grammar (that ...
3
votes
1answer
156 views

Performance issues when parsing code [closed]

I was wondering about performance issues when parsing a source file that is being edited by the user (for example, when you need to give a syntax highlight). I think that the simplest approach is to ...
3
votes
1answer
204 views

What does it mean that StAX parsers aren't complete or correct?

I've been browsing the net and found theses two slides on site of XOM (XML object model): slide1 slide2 Where they refer to SAX(push) and StAX(pull) parsers. So I'm wondering, what does it mean ...
3
votes
1answer
637 views

How can I test a parser for a bespoke XML schema?

I'm parsing a bespoke XML format into an object graph using .NET 4.0. My parser is using the System.XML namespace internally, I'm then interrogating the relevant properties of XmlNodes to create my ...
2
votes
3answers
2k views

c++ write own xml parser vs using tinyxml

I am currently in a task to generate an XML file for an srt text file containing timestamps and corresponding text. To generate an exe file which accepts file name input and outputs the relevant XML ...
2
votes
2answers
154 views

parsing terminology: comments+whitespaces vs actual code

In languages like c/c++ spacing and comments are ignored and only actual code gets into compiler. I'm interested if there is accepted way of naming these two things? comments & spacing ...
2
votes
2answers
2k views

Is there a more modern program than lex or yacc, which does not require JVM?

Is there a "modern" bison and flex equivalent which does not require the JVM or .NET or similar "heavy" runtimes? Thanks for comments, edit: By modern, I mean for example Antlr and another one in ...
2
votes
2answers
130 views

When to use ANTLR and when to use a parsing library

I've always wanted to learn how to write a compiler - I've decided to use ANTLR, and am currently reading through the book (its very good by the way) I'm pretty new to this, so go easy, but the jist ...
2
votes
4answers
216 views

The right place to embed a parser : Server or the Client?

I'm writing a database management software. It has a client-server architecture where the server has the piece of code to store and retrieve. The client has to get the input from the user, connects to ...
2
votes
1answer
359 views

REST efficiency on count and sum methods

For example, if I have a Customer Transactions Table and I create a REST for it. The fields are: date, description, and total_amount. I am trying to figure out which one is much more efficient when ...
2
votes
1answer
993 views

How to add precedence to LALR parser like in YACC?

Please note, I am asking about writing LALR parser, not writing rules for LALR parser. What I need is... ...to mimic YACC precedence definitions. I don't know how it is implemented, and below I ...
2
votes
1answer
417 views

Idea of an algorithm to detect a website's navigation structure?

Currently I am in the process of developing an importer of any existing, arbitrary (static) HTML website into the upcoming release of our CMS. While the downloading the files is solved successfully, ...
2
votes
3answers
2k views

Writing a CSS parser in C#. What do you think is the best strategy?

I'm in the middle of writing a CSS parser in C#. I'm well under way, but I also have those times where I wonder if I'm taking the best approach. The things I've considered are: Feed the CSS grammar ...
2
votes
1answer
168 views

content fingerprint algorithm

I have a database containing just simple URLs. It is as simple as it sounds for now and URL can link to a website or a document(i.e. anything parseable to text). Now I have a simple code which ...
2
votes
2answers
3k views

An ideal way to decode JSON documents in C?

Assuming I have an API to consume that uses JSON as a data transmission method, what is an ideal way to decode the JSON returned by each API resource? For example, in Java I'd create a class for each ...
2
votes
1answer
266 views

Practical reference for learning about graph reduction

Are there any practical references (with actual examples) for getting started implementing a small, lazy functional programming language with graph reduction? A reference that included the lexing and ...
2
votes
1answer
250 views

Best way to parse optional grammar rules?

I started to write a hand written parser just for fun. For simple rules it is working, but I have problem with the optional grammar rules. I marked the optional rules with a question mark. Here is a ...
2
votes
1answer
467 views

How to choose a proper parser generator for PHP

Some programmers avoid regexes in some situations (see this popular @nickf comment), perhaps using a parsing framework such as Lex/Yacc. Others prefer to stay within PHP, perhaps using regular ...
2
votes
2answers
4k views

Fastest C++ XML parsing library

I have thousands of .xml files from size 1MB-45MB (no DTDs). I need to parse and further manipulate these XML files before generating separate .xml files with the results of my regex. What the ...
2
votes
2answers
233 views

Building a string parser for user command and control?

My goal is to build a command parser that has basic syntax and multiple possible branches at each point. These commands come from users of the system and are text input (no GUI). The basic syntax is ...
2
votes
0answers
63 views

Loop Unfolding and Named Significant Bits

I've been writing a Parser Compiler for the last seven or so years, and I recently got to the point (yet again, never satisfied) of structuring the portion dealing with the portions of the language ...
2
votes
0answers
278 views

Haskell, Rust, or D for POSIX shell implementation? [closed]

I am planning on writing my own Bourne shell. It will be full-featured, capable of being used as a system /bin/sh. The shell will be implemented very differently from other Bourne shells, however. ...
2
votes
1answer
218 views

How and when should I design a simple mark-up language parser? [closed]

I want to write a simple markup language with its rendering engine. First, I am not completely sure when I should try this... I am only 12... But I am competent in C++ having learned through the Web ...
2
votes
0answers
155 views

Implementing semantic actions in table driven predictive parsing

When doing table driven predictive parsing on an LL(1) grammar, (as explained in good detail here for example), how can we augment the algorithm to allow processing of semantic actions while doing the ...
2
votes
1answer
342 views

LL(∞) and left-recursion [closed]

I want to understand the relation between LL/LR grammars and the left-recursion problem (for any question I know parcially the answer, but I ask them as I don't know nothing, because I am a little ...
1
vote
5answers
913 views

I need to develop a parser. Can I use Lex and Yacc for the purpose?

I need to extract very particular data from log files(of different types and formats). Since I am a recent college passout; my mind ran to using Lex and Yacc for the purpose. Now I have the following ...
1
vote
2answers
190 views

Parser and interpreter knowledge as a way to gauge programmer ability [closed]

This is only anecdotal evidence but from my past encounters with programmers at various workplaces the programmers that understand the fundamentals of parsing and interpreting seem to be overall ...
1
vote
1answer
173 views

Grammar: start: (a b)? a c; Input: a d. Which error correct at position 2? 1. expected “b”, “c”. OR expected “c”

I am writing a parser (a parser generator for PEGs) and am trying to figure out how to report errors. Grammar: rule: (a b)? a c ; Input: a d Question: Which error message correct at position 2 ...
1
vote
2answers
52 views

Passing context around AST nodes

I have various objects inside my AST, such as IfBlock, FunctionBlock, LogicExpression, etc. All of those objects share a context, which is basically a hashmap with some variables. It's a very simple ...
1
vote
2answers
225 views

Lexer/Parser for multidimensional Languages

How does Lexer/Parser work in a 2D programming language like Funciton in order to transform such an unusual source-code to the correct AST?
1
vote
4answers
450 views

Is it possible to create a single tokenizer to parse this?

This extends off this other Q&A thread, but is going into details that are out of scope from the original question. I am generating a parser that is to parse a context-sensitive grammar which can ...