Parse::RecDescent is a large, object-oriented, well-documented Perl 5 module. It incrementally generates top-down recursive-descent text parsers from simple yacc-like grammar specifications.
This module is best for learning about parsing, for designing complex (context-sensitive or dynamic) grammars, or any situation where input is short or performance is no issue.
For alternatives, try the "official" successor Regexp::Grammars; or Parse::Yapp or Parse::EYapp.
Questions tagged [parse-recdescent]
21 questions
4
votes
1 answer
Disable critic for an entire file - Parse::RecDescent precompiled parser & PerlCritic/Tidyall
I'm trying to remove an error from my sanity-checking [when I push code to my git repo, there's a hook that checks the code with perltidy & critic... using tidyall as the handler.]
The specific issue I have is with a pre-compiled Grammar Parser....…
CodeGorilla
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3
votes
1 answer
Should I use Parse::RecDescent or Regexp::Grammars to extract tables from documents?
I have lots of large plain text documents I wish to parse with perl. Each document has mostly English paragraphs in it, with a couple of plain text marked up tables in each document.
I have created a grammar to describe the table structure, but am…
Matthew Lock
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3
votes
2 answers
Parse::RecDescent : Parsing nested arithmetic expression?
Currently I use this to parse Arithmetic expressions :
expr : '(' expr ')'
| number op expr
| variable op expr
| number
| variable
|
It works for simple expressions, but can't handle nested…
sten
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3
votes
1 answer
Is Perl's Parse::RecDescent thread safe?
I have a web application that uses a parser created with Parse::RecDescent. A parser object is needed in several parts of the application and since the parser takes quite a bit of memory I have up to now treated the parser object as a singleton.…
oyse
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3
votes
1 answer
Parse::RecDescent grammar not working as expected
All I managed to get working is STRING, PARAMS, VARIABLE and FUNCNAME
There seems to be a problem with FUNCTION, but I just can't see it.
use strict;
use Parse::RecDescent;
$::RD_ERRORS = 1; # Make sure the parser dies when it encounters an…
AlfredoVR
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3
votes
1 answer
Parsing string with nested parentheses using Parse::RecDescent
I'm trying to use Parse::RecDescent make a parser which can parse parenthetical expressions and the unary operator ?.
What I have so far is failing when I create the parser because the rule expression is left-recursive:
use strict;
use warnings;
use…
Nate Glenn
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2
votes
1 answer
Interpolating variables in a Parse::RecDescent regex
I'm working on a Parse::RecDescent grammar to read a given human-readable set of rules and then spit out a file that is much easier for a computer to read.
One of the tokens is a list of "keywords"; about 26 different keywords. These may change over…
Paul Nathan
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2
votes
2 answers
parsing different files of the same grammar and calculating file to file similarities
I've got a bunch of ACPI Source Language files and I want to calculate file to file similarities between them. I thought of using something like Perl's Parse::RecDescent
but I am stuck at:
1) Translating the ACPI Grammar…
719016
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2
votes
1 answer
Whitespace-important parsing with Parse::RecDescent (eg. HAML, Python)
I'm trying to parse HAML (haml.info) with Parse::RecDescent. If you don't know haml, the problem in question is the same as parsing Python - blocks of syntax are grouped by the indentation level.
Starting with a very simple subset, I've tried a few…
Mark
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2
votes
1 answer
Collecting data with Parse::RecDescent
I have a list of strings (30,000+) which are a collection of statements. Logically, Parse::RecDescent is the tool to use to parse the string to gather the data, but I just can't get my head round the construction of the grammar specification.
The…
CodeGorilla
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1
vote
2 answers
Parse::RecDescent - getting information from it
I'm working with the Parse::RecDescent parser in Perl, and I seem to have the most terrible time getting information from it. The information readily available online does not seem to have non-trivial examples.
Here is the code:
event_function:…
Paul Nathan
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1
vote
1 answer
Why does my Parse::RecDescent give me all these warnings and errors?
Having a lot of pain with the following Perl file parsing code [last reply on PM @http://www.perlmonks.org/index.pl?node_id=754947] below:
#!/usr/bin/perl -w
use strict;
use warnings;
#use diagnostics;
use Parse::RecDescent;
use Data::Dumper;
#…
PoorLuzer
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1
vote
1 answer
Parse::RecDescent and operators with quotes
I have something like the following:
((x=2 or y=3 ) and (r=3 and c=3) or (x=5 and g=6))
I defined:
Token : /\w \= \d/
operator or|and
expression : token operator(s)
quoted_expression : "("expression")"
query : expression…
jsor
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1
vote
1 answer
Parse::RecDescent and Grammar
I defined the following grammar using Parse::RecDescent
my $grammar = q{
top : operand equal value { print $item{value} }
operand: /\w+/
equal : /\=/
value : { my $value = extract_quotelike($text) ;$return =$value;}
};
which i wants it…
jsor
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1
vote
0 answers
parsing syntax with Perl
I am using Parse::RecDescent(the below code) to parse something like this
this x=2 and y=2 and z=3
why the below code only print x!=2 and not all the above line (i.e x!=2 and y!=2 and z!=3) even the above line is parsed by the below code any idea…
jsor
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