67 lines
1.8 KiB
Ruby
67 lines
1.8 KiB
Ruby
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# The base class for all your parsers. Use as follows:
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#
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# require 'parslet'
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#
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# class MyParser < Parslet::Parser
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# rule(:a) { str('a').repeat }
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# root(:a)
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# end
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#
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# pp MyParser.new.parse('aaaa') # => 'aaaa'
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# pp MyParser.new.parse('bbbb') # => Parslet::Atoms::ParseFailed:
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# # Don't know what to do with bbbb at line 1 char 1.
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#
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# Parslet::Parser is also a grammar atom. This means that you can mix full
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# fledged parsers freely with small parts of a different parser.
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#
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# Example:
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# class ParserA < Parslet::Parser
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# root :aaa
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# rule(:aaa) { str('a').repeat(3,3) }
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# end
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# class ParserB < Parslet::Parser
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# root :expression
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# rule(:expression) { str('b') >> ParserA.new >> str('b') }
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# end
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#
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# In the above example, ParserB would parse something like 'baaab'.
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#
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class Parslet::Parser < Parslet::Atoms::Base
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include Parslet
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class <<self # class methods
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# Define the parsers #root function. This is the place where you start
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# parsing; if you have a rule for 'file' that describes what should be
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# in a file, this would be your root declaration:
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#
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# class Parser
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# root :file
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# rule(:file) { ... }
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# end
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#
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# #root declares a 'parse' function that works just like the parse
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# function that you can call on a simple parslet, taking a string as input
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# and producing parse output.
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#
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# In a way, #root is a shorthand for:
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#
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# def parse(str)
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# your_parser_root.parse(str)
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# end
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#
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def root(name)
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define_method(:root) do
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self.send(name)
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end
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end
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end
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def try(source, context, consume_all)
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root.try(source, context, consume_all)
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end
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def to_s_inner(prec)
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root.to_s(prec)
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end
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end |