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Questions tagged [parsing]

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

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38
votes
2answers
8k views

Do modern languages still use parser generators?

I was researching about the gcc compiler suite on wikipedia here, when this came up: GCC started out using LALR parsers generated with Bison, but gradually switched to hand-written recursive-...
14
votes
3answers
28k views

Generic file parser design in Java using the Strategy pattern

I am working on a product in which the responsibility of one of the modules is to parse XML files and dump the required content in a database. Even though the present requirement is only to parse XML ...
5
votes
2answers
261 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
3answers
2k views

How exactly is bytecode “parsed”?

How is Bytecode "parsed"? It is my understand that Bytecode is a binary, intermediate representation of the syntax of a given programming language. Certain programming languages convert their source ...
9
votes
2answers
5k views

Language parsing to find important words

I'm looking for some input and theory on how to approach a lexical topic. Let's say I have a collection of strings, which may just be one sentence or potentially multiple sentences. I'd like to ...
24
votes
6answers
2k views

What are the arguments against parsing the Cthulhu way?

I have been assigned the task of implementing a Domain Specific Language for a tool that may become quite important for the company. The language is simple but not trivial, it already allows nested ...
81
votes
12answers
28k views

Should I use a parser generator or should I roll my own custom lexer and parser code?

What specific advantages and disadvantages of each way to working on a programming language grammar? Why/When should I roll my own? Why/When should I use a generator?
27
votes
8answers
5k views

Is it possible to statically predict when to deallocate memory---from source code only?

Memory (and resource locks) are returned to the OS at deterministic points during a program's execution. The control flow of a program by itself is enough to know where, for sure, a given resource can ...
11
votes
5answers
44k views

Getting data from a webpage in a stable and efficient way

Recently I've learned that using a regex to parse the HTML of a website to get the data you need isn't the best course of action. So my question is simple: What then, is the best / most efficient and ...
10
votes
3answers
2k views

Writing a Compiler Compiler - Insight on Use and Features

This is part of a series of questions which focuses on the sister project to the Abstraction Project, which aims to abstract the concepts used in language design in the form of a framework. The ...
18
votes
5answers
6k views

Are separate parsing and lexing passes good practice with parser combinators?

When I began to use parser combinators my first reaction was a sense of liberation from what felt like an artificial distinction between parsing and lexing. All of a sudden everything was just ...
5
votes
2answers
3k views

How is a abstract syntax tree used to execute source code?

After researching how a parser generates an AST, I believe that I can know attempt to create one. Before I started on this project, I began to ponder what I should be done next after creating a AST ...
2
votes
2answers
1k 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 ...
14
votes
2answers
6k views

Do compilers utilize multithreading for faster compile times?

If I remember my compilers course correctly, the typical compiler has the following simplified outline: A lexical analyzer scans (or calls some scanning function on) the source code character-by-...
14
votes
5answers
4k views

Coming up with tokens for a lexer

I'm writing a parser for a markup language that I have created (writing in python, but that's not really relevant to this question -- in fact if this seems like a bad idea, I'd love a suggestion for a ...
8
votes
3answers
1k views

Clarification about Grammars , Lexers and Parsers

Background info (May Skip): I am working on a task we have been set at uni in which we have to design a grammar for a DSL we have been provided with. The grammar must be in BNF or EBNF. As well as ...
1
vote
4answers
1k 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 ...
6
votes
4answers
3k views

What is the responsibility or benefit of a Tokenizer?

Suppose I had a grammar like: object { members } members pair pair string : value value number string string " chars " chars char char chars number digit ...
5
votes
5answers
2k views

How to store math expression in c++ list

I am parsing a infix math expression to a postfix form. I want to store it in a list like [4.5, 3, 0.25, +, -] so that I can process it once it's parsed. I could store it in a string again, but I ...
3
votes
2answers
7k 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
2answers
326 views

What is the name of a grammar which can change its tokenizer in mid parse?

I was creating a language and discovered that my language tokenizer would have to change depending where in the parse it is. I.e. abc[1] would be parsed as 4 tokens (abc, [, 1, ]), where as { abc[1] }...