71 lines
2.2 KiB
Factor
71 lines
2.2 KiB
Factor
! Copyright (C) 2003, 2005 Slava Pestov.
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! See http://factor.sf.net/license.txt for BSD license.
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IN: errors
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USING: kernel kernel-internals ;
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: catchstack* ( -- cs ) 6 getenv ; inline
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: catchstack ( -- cs ) catchstack* clone ; inline
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: set-catchstack ( cs -- ) clone 6 setenv ; inline
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IN: kernel
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USING: namespaces sequences ;
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TUPLE: continuation data c call name catch ;
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: c-stack ( -- c-stack )
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#! In the interpreter, this is a no-op. The compiler has an
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#! an intrinsic for this word.
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f ;
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: set-c-stack ( c-stack -- )
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[ "not supported" throw ] when ;
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: interpret ( quot -- )
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#! Call the quotation in the interpreter. When compiled,
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#! the quotation is ignored.
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call ;
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: continuation ( -- interp )
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#! The continuation is reified from after the *caller* of
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#! this word returns. It must be declared inline for this
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#! invariant to be preserved in compiled code too.
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datastack c-stack callstack [ dup pop* dup pop* ] interpret
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namestack catchstack <continuation> ; inline
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: >continuation< ( continuation -- data c call name catch )
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[ continuation-data ] keep
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[ continuation-c ] keep
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[ continuation-call ] keep
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[ continuation-name ] keep
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continuation-catch ; inline
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: ifcc ( terminator balance -- | quot: continuation -- )
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#! Note that the branch at the end must not be optimized out
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#! by the compiler.
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[
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continuation
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dup continuation-data f over push f swap push dup
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] call 2swap if ; inline
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: callcc0 ( quot -- | quot: continuation -- )
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#! Call a quotation with the current continuation, which may
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#! be restored using continue.
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[ drop ] ifcc ; inline
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: continue ( continuation -- )
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#! Restore a continuation.
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>continuation< set-catchstack set-namestack set-callstack
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>r set-datastack r> set-c-stack ; inline
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: (continue-with) 9 getenv ;
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: callcc1 ( quot -- | quot: continuation -- )
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#! Call a quotation with the current continuation, which may
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#! be restored using continue-with.
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[ drop (continue-with) ] ifcc ; inline
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: continue-with ( object continuation -- object )
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#! Restore a continuation, and place the object in the
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#! restored data stack.
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swap 9 setenv continue ; inline
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