32 lines
		
	
	
		
			944 B
		
	
	
	
		
			Factor
		
	
	
			
		
		
	
	
			32 lines
		
	
	
		
			944 B
		
	
	
	
		
			Factor
		
	
	
| ! Copyright (C) 2005, 2009 Slava Pestov.
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| ! See http://factorcode.org/license.txt for BSD license.
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| USING: fry help.markup help.topics kernel math sequences ;
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| IN: help.crossref
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| 
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| : article-links ( topic elements -- seq )
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|     [ article-content ] dip collect-elements ;
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| 
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| : article-children ( topic -- seq )
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|     { $subsection $subsections } article-links [ >link ] map ;
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| 
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| : help-path ( topic -- seq )
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|     [ article-parent ] follow rest ;
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| 
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| : set-article-parents ( parent article -- )
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|     article-children [ set-article-parent ] with each ;
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| 
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| : xref-article ( topic -- )
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|     dup set-article-parents ;
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| 
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| : prev/next ( obj seq n -- obj' )
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|     [ [ index dup ] keep ] dip swap
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|     '[ _ + _ ?nth ] when ;
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| 
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| : prev/next-article ( article n -- article' )
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|     [ dup article-parent dup ] dip
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|     '[ article-children _ prev/next ] [ 2drop f ] if ;
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| 
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| : prev-article ( article -- prev ) -1 prev/next-article ;
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| 
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| : next-article ( article -- next ) 1 prev/next-article ;
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