45 lines
2.0 KiB
Factor
45 lines
2.0 KiB
Factor
! Copyright (C) 2010 Doug Coleman.
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! See http://factorcode.org/license.txt for BSD license.
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USING: help.markup help.syntax io kernel quotations words
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math ;
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IN: io.streams.throwing
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HELP: stream-exhausted
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{ $values
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{ "n" integer } { "stream" "an input stream" } { "word" word }
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}
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{ $description "The exception that gets thrown when a stream is exhausted." } ;
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HELP: stream-throw-on-eof
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{ $values
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{ "stream" "an input stream" } { "quot" quotation }
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}
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{ $description "Wraps a stream in a " { $link <throws-on-eof-stream> } " tuple and calls the quotation with this stream as the " { $link input-stream } " variable. Causes a " { $link stream-exhausted } " exception to be thrown upon stream exhaustion. The stream is left open after this combinator returns." }
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"This example will throw a " { $link stream-exhausted } " exception:"
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{ $unchecked-example """USING: io.streams.throwing prettyprint ;
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"abc" <string-reader> [ 4 read ] stream-throw-on-eof"""
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""
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} ;
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HELP: throw-on-eof
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{ $values
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{ "quot" quotation }
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}
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{ $description "Wraps the value stored in the " { $link input-stream } " variable and causes a stream read that exhausts the input stream to throw a " { $link stream-exhausted } " exception. The stream is left open after this combinator returns." } $nl
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"This example will throw a " { $link stream-exhausted } " exception:"
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{ $unchecked-example """USING: io.streams.throwing prettyprint ;
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"abc" [ [ 4 read ] throw-on-eof ] with-string-reader"""
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""
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} ;
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ARTICLE: "io.streams.throwing" "Throwing exceptions on stream exhaustion"
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"The " { $vocab-link "io.streams.throwing" } " vocabulary implements combinators for changing the behavior of a stream to throw an exception upon exhaustion instead of returning " { $link f } "." $nl
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"A general combinator to wrap any stream:"
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{ $subsections stream-throw-on-eof }
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"A combinator for the " { $link input-stream } " variable:"
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{ $subsections throw-on-eof }
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"The exception itself:"
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{ $subsections stream-exhausted } ;
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ABOUT: "io.streams.throwing"
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