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Diffstat (limited to 'lib/psych/parser.rb')
-rw-r--r-- | lib/psych/parser.rb | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/lib/psych/parser.rb b/lib/psych/parser.rb new file mode 100644 index 0000000000..0e38a4ae7d --- /dev/null +++ b/lib/psych/parser.rb @@ -0,0 +1,44 @@ +module Psych + ### + # YAML event parser class. This class parses a YAML document and calls + # events on the handler that is passed to the constructor. The events can + # be used for things such as constructing a YAML AST or deserializing YAML + # documents. It can even be fed back to Psych::Emitter to emit the same + # document that was parsed. + # + # See Psych::Handler for documentation on the events that Psych::Parser emits. + # + # Here is an example that prints out ever scalar found in a YAML document: + # + # # Handler for detecting scalar values + # class ScalarHandler < Psych::Handler + # def scalar value, anchor, tag, plain, quoted, style + # puts value + # end + # end + # + # parser = Psych::Parser.new(ScalarHandler.new) + # parser.parse(yaml_document) + # + # Here is an example that feeds the parser back in to Psych::Emitter. The + # YAML document is read from STDIN and written back out to STDERR: + # + # parser = Psych::Parser.new(Psych::Emitter.new($stderr)) + # parser.parse($stdin) + # + # Psych uses Psych::Parser in combination with Psych::TreeBuilder to + # construct an AST of the parsed YAML document. + + class Parser + # The handler on which events will be called + attr_accessor :handler + + ### + # Creates a new Psych::Parser instance with +handler+. YAML events will + # be called on +handler+. See Psych::Parser for more details. + + def initialize handler = Handler.new + @handler = handler + end + end +end |