57 lines
2.6 KiB
Ruby
57 lines
2.6 KiB
Ruby
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module Parslet
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module ErrorReporter
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# An error reporter has two central methods, one for reporting errors at
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# the current parse position (#err) and one for reporting errors at a
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# given parse position (#err_at). The reporter can return an object (a
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# 'cause') that will be returned to the caller along with the information
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# that the parse failed.
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#
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# When reporting errors on the outer levels of your parser, these methods
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# get passed a list of error objects ('causes') from the inner levels. In
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# this default implementation, the inner levels are considered error
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# subtrees and are appended to the generated tree node at each level,
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# thereby constructing an error tree.
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#
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# This error tree will report in parallel with the grammar structure that
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# failed. A one-to-one correspondence exists between each error in the
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# tree and the parslet atom that produced that error.
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#
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# The implementor is really free to use these return values as he sees
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# fit. One example would be to return an error state object from these
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# methods that is then updated as errors cascade up the parse derivation
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# tree.
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#
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class Tree
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# Produces an error cause that combines the message at the current level
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# with the errors that happened at a level below (children).
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#
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# @param atom [Parslet::Atoms::Base] parslet that failed
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# @param source [Source] Source that we're using for this parse. (line
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# number information...)
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# @param message [String, Array] Error message at this level.
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# @param children [Array] A list of errors from a deeper level (or nil).
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# @return [Cause] An error tree combining children with message.
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#
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def err(atom, source, message, children=nil)
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position = source.pos
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Cause.format(source, position, message, children)
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end
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# Produces an error cause that combines the message at the current level
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# with the errors that happened at a level below (children).
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#
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# @param atom [Parslet::Atoms::Base] parslet that failed
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# @param source [Source] Source that we're using for this parse. (line
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# number information...)
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# @param message [String, Array] Error message at this level.
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# @param pos [Fixnum] The real position of the error.
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# @param children [Array] A list of errors from a deeper level (or nil).
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# @return [Cause] An error tree combining children with message.
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#
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def err_at(atom, source, message, pos, children=nil)
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position = pos
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Cause.format(source, position, message, children)
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end
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end
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end
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end
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