RosettaCodeData/Task/Align-columns/Factor/align-columns.factor

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Factor

USING: fry io kernel math math.functions math.order sequences
splitting strings ;
IN: rosetta.column-aligner
CONSTANT: example-text "Given$a$text$file$of$many$lines,$where$fields$within$a$line$
are$delineated$by$a$single$'dollar'$character,$write$a$program
that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$
column$are$separated$by$at$least$one$space.
Further,$allow$for$each$word$in$a$column$to$be$either$left$
justified,$right$justified,$or$center$justified$within$its$column."
: split-and-pad ( text -- lines )
"\n" split [ "$" split harvest ] map
dup [ length ] [ max ] map-reduce
'[ _ "" pad-tail ] map ;
: column-widths ( columns -- widths )
[ [ length ] [ max ] map-reduce ] map ;
SINGLETONS: +left+ +middle+ +right+ ;
GENERIC: align-string ( str n alignment -- str' )
M: +left+ align-string drop CHAR: space pad-tail ;
M: +right+ align-string drop CHAR: space pad-head ;
M: +middle+ align-string
drop
over length - 2 /
[ floor CHAR: space <string> ]
[ ceiling CHAR: space <string> ] bi surround ;
: align-columns ( columns alignment -- columns' )
[ dup column-widths ] dip '[
[ _ align-string ] curry map
] 2map ;
: print-aligned ( text alignment -- )
[ split-and-pad flip ] dip align-columns flip
[ [ write " " write ] each nl ] each ;