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sbmpei
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Файл:8-12
.rbclass XML
# Create an instance of this class, specifying a stream or object to
# hold the output. This can be any object that responds to <<(String).
def initialize(out)
@out = out # Remember where to send our output
end
# Output the specified object as CDATA, return nil.
def content(text)
@out << text.to_s
nil
end
# Output the specified object as a comment, return nil.
def comment(text)
@out << "<!-- #{text} -->"
nil
end
# Output a tag with the specified name and attributes.
# If there is a block invoke it to output or return content.
# Return nil.
def tag(tagname, attributes={})
# Output the tag name
@out << "<#{tagname}"
# Output the attributes
attributes.each {|attr,value| @out << " #{attr}='#{value}'" }
if block_given?
# This block has content
@out << '>' # End the opening tag
content = yield # Invoke the block to output or return content
if content # If any content returned
@out << content.to_s # Output it as a string
end
@out << "</#{tagname}>" # Close the tag
else
# Otherwise, this is an empty tag, so just close it.
@out << '/>'
end
nil # Tags output themselves, so they don't return any content
end
# The code below is what changes this from an ordinary class into a DSL.
# First: any unknown method is treated as the name of a tag.
alias method_missing tag
# Second: run a block in a new instance of the class.
def self.generate(out, &block)
XML.new(out).instance_eval(&block)
end
end
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