Parslet is a parsing Ruby library based on PEG (Parsing Expression Grammar)
Questions tagged [parslet]
35 questions
10
votes
2 answers
Indentation sensitive parser using Parslet in Ruby?
I am attempting to parse a simple indentation sensitive syntax using the Parslet library within Ruby.
The following is an example of the syntax I am attempting to parse:
level0child0
level0child1
level1child0
level1child1
level2child0
…
RyanScottLewis
- 13,396
- 16
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5
votes
2 answers
Ruby parslet: parsing multiple lines
I'm looking for a way to match multiple lines Parslet.
The code looks like this:
rule(:line) { (match('$').absent? >> any).repeat >> match('$') }
rule(:lines) { line.repeat }
However, lines will always end up in an infinite loop which is because…
Danyel
- 2,180
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3
votes
3 answers
How to define a fixed-width constraint in parslet
I am looking into parslet to write alot of data import code. Overall, the library looks good, but I'm struggling with one thing. Alot of our input files are fixed width, and the widths differ between formats, even if the actual field doesn't. For…
Jonathan
- 2,043
- 2
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3
votes
2 answers
Parslet: recognise anything but a given keyword
I'm trying to write a Ruby/Parslet parser for Handlebars but I'm getting stuck with the {{ else }} keyword.
To explain brieflt for those who do not use Handlebars, an if/else is written this way:
{{#if my_condition}}
show something
{{else}}
show…
Vincent
- 620
- 7
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3
votes
1 answer
Simple parslet parser for comma-delimited list does not work
Why does the following Parslet parser not work for parsing comma-delimited lists? When I parse, it gets stuck and does not provide an error message:
class TestParser < Parslet::Parser
rule(:name) { match['a-z'].repeat >> str(',').maybe }
…
Sean Mackesey
- 10,701
- 11
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- 66
3
votes
2 answers
How do I handle C-style comments in Ruby using Parslet?
Taking as a starting point the code example from the Parslet's own creator (available in this link) I need to extend it so as to retrieve all the non-commented text from a file written in a C-like syntax.
The provided example is able to successfully…
zml
- 617
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- 14
2
votes
2 answers
Parse before storing in MVC
I'm getting started with parsing data and getting some structure from user supplied strings (mostly pulling out digits and city names).
I've run a bit of code in the ruby interpreter, and now I want to use that same code in a web application.
I'm…
pedalpete
- 21,076
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2
votes
2 answers
Parslet Not parsing whole string
For the following Parslet Parser
require 'parslet'
require 'parslet/convenience'
class Lines < Parslet::Parser
rule(:open_tag) {str('[')}
rule(:close_tag) {str(']')}
rule(:data) {str('name') | str('name_id') }
rule(:text) {…
Darshan Patel
- 3,176
- 6
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- 49
2
votes
1 answer
Ruby & Lmstat : parslet and structured multi-line block : where to put the newline statement?
I have a Flexlm/Flexnet licenses service and I want parse the outputs of this service. All output are structured block of multi-lines. My first step is to parse the output of lmutil lmstat -c -a to have the usage of licences and…
Scapin
- 123
- 5
2
votes
1 answer
How do I use Parslet with strings not Parslet Slices
I've started using Parslet to parse some custom data. In the examples, the resulting parsed data is something like:
{ :custom_string => "data"@6 }
And I've created the Transform something like
rule(:custom_string => simple(:x)) { x.to_s }
But it…
Simmo
- 1,717
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2
votes
1 answer
Parse markdown indented code block
I am trying to parse Markdown using a grammar written with Parslet. However, I cannot get past indented code blocks because everything I tried so far got stuck in recursion. They look like this:
This is a indented code block.
Second line.
…
JMH
- 1,289
- 1
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- 19
2
votes
1 answer
How to perform lookaheads in a PEG without making the rule too greedy?
I'm writing a parser in Parslet. In the file I want to parse, I have the following structure:
Item #1
denis calls 20
anna raises 60
denis calls 40
Item #2
another player raises 60
anna calls 60
...
To parse the actions, I did the following:
As I…
Denis Lins
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2
votes
1 answer
Why does Parslet (in Ruby) return an empty array when parsing an empty string literal?
I'm playing with parslet. This is trivial parser which shows me some non-obvious behavior.
require 'parslet'
class Parser < Parslet::Parser
rule(:quote) { str('"') }
rule(:escape_char) { str('\\') }
def quoted(term)
quote >> term >>…
Viacheslav Kovalev
- 1,745
- 12
- 17
2
votes
2 answers
Parslet subtree doesn't fire
Resume (I shrinked down the following long story to the simple problem)
tree = {:properties => [{:a => 'b'}, {:c => 'd'}]}
big_tree = {:properties => [{:a => 'b'}, {:c => 'd'}], :moves => [{:a => 'b'}, {:c => 'd'}]}
trans = Parslet::Transform.new…
Dahan
- 163
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- 10
2
votes
2 answers
Parslet Alternatives Not parsing whole string
I have the following specs
it "parses a document with only an expression" do
puts parser.document.should parse("[b]Hello World[/b]")
end
it "parses a document with only text" do
puts parser.document.should parse(" Hello World")
end
…
DVG
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