35 lines
1.0 KiB
Factor
35 lines
1.0 KiB
Factor
! Copyright (C) 2004, 2005 Slava Pestov.
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! See http://factor.sf.net/license.txt for BSD license.
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IN: kernel
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USING: kernel-internals lists ;
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DEFER: callcc1
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IN: errors
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TUPLE: no-method object generic ;
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: no-method ( object generic -- )
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#! We 2dup here to leave both values on the stack, for
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#! post-mortem inspection.
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<no-method> throw ;
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! This is a very lightweight exception handling system.
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: catchstack ( -- cs ) 6 getenv ;
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: set-catchstack ( cs -- ) 6 setenv ;
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: >c ( catch -- ) catchstack cons set-catchstack ;
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: c> ( catch -- ) catchstack uncons set-catchstack ;
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: catch ( try catch -- )
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#! Call the try quotation. If an error occurs restore the
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#! datastack, push the error, and call the catch block.
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#! If no error occurs, push f and call the catch block.
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[ >c >r call c> drop f r> f ] callcc1 rot drop swap call ;
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: rethrow ( error -- )
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#! Use rethrow when passing an error on from a catch block.
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#! For convinience, this word is a no-op if error is f.
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[ c> call ] when* ;
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GENERIC: error. ( error -- )
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