vendored parslet, deemed stable enough and better without dependency
This commit is contained in:
67
lib/parslet/parser.rb
Normal file
67
lib/parslet/parser.rb
Normal file
@@ -0,0 +1,67 @@
|
||||
|
||||
# The base class for all your parsers. Use as follows:
|
||||
#
|
||||
# require 'parslet'
|
||||
#
|
||||
# class MyParser < Parslet::Parser
|
||||
# rule(:a) { str('a').repeat }
|
||||
# root(:a)
|
||||
# end
|
||||
#
|
||||
# pp MyParser.new.parse('aaaa') # => 'aaaa'
|
||||
# pp MyParser.new.parse('bbbb') # => Parslet::Atoms::ParseFailed:
|
||||
# # Don't know what to do with bbbb at line 1 char 1.
|
||||
#
|
||||
# Parslet::Parser is also a grammar atom. This means that you can mix full
|
||||
# fledged parsers freely with small parts of a different parser.
|
||||
#
|
||||
# Example:
|
||||
# class ParserA < Parslet::Parser
|
||||
# root :aaa
|
||||
# rule(:aaa) { str('a').repeat(3,3) }
|
||||
# end
|
||||
# class ParserB < Parslet::Parser
|
||||
# root :expression
|
||||
# rule(:expression) { str('b') >> ParserA.new >> str('b') }
|
||||
# end
|
||||
#
|
||||
# In the above example, ParserB would parse something like 'baaab'.
|
||||
#
|
||||
class Parslet::Parser < Parslet::Atoms::Base
|
||||
include Parslet
|
||||
|
||||
class <<self # class methods
|
||||
# Define the parsers #root function. This is the place where you start
|
||||
# parsing; if you have a rule for 'file' that describes what should be
|
||||
# in a file, this would be your root declaration:
|
||||
#
|
||||
# class Parser
|
||||
# root :file
|
||||
# rule(:file) { ... }
|
||||
# end
|
||||
#
|
||||
# #root declares a 'parse' function that works just like the parse
|
||||
# function that you can call on a simple parslet, taking a string as input
|
||||
# and producing parse output.
|
||||
#
|
||||
# In a way, #root is a shorthand for:
|
||||
#
|
||||
# def parse(str)
|
||||
# your_parser_root.parse(str)
|
||||
# end
|
||||
#
|
||||
def root(name)
|
||||
define_method(:root) do
|
||||
self.send(name)
|
||||
end
|
||||
end
|
||||
end
|
||||
|
||||
def try(source, context, consume_all)
|
||||
root.try(source, context, consume_all)
|
||||
end
|
||||
|
||||
def to_s_inner(prec)
|
||||
root.to_s(prec)
|
||||
end
|
||||
end
|
Reference in New Issue
Block a user