40 lines
1.1 KiB
Factor
40 lines
1.1 KiB
Factor
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IN: format
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USE: kernel
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USE: math
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USE: namespaces
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USE: strings
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USE: test
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: decimal-split ( string -- string string )
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#! Split a string before and after the decimal point.
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dup "." index-of dup -1 = [ drop f ] [ str// ] ifte ;
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: decimal-tail ( count str -- string )
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#! Given a decimal, trims all but a count of decimal places.
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[ str-length min ] keep str-head ;
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: decimal-cat ( before after -- string )
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#! If after is of zero length, return before, otherwise
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#! return "before.after".
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dup str-length 0 = [
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drop
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] [
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"." swap cat3
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] ifte ;
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: decimal-places ( num count -- string )
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#! Trims the number to a count of decimal places.
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>r decimal-split dup [
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r> swap decimal-tail decimal-cat
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] [
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r> 2drop
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] ifte ;
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[ "123" ] [ 4 "123" decimal-tail ] unit-test
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[ "12" ] [ 2 "123" decimal-tail ] unit-test
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[ "123" ] [ "123" 2 decimal-places ] unit-test
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[ "123.12" ] [ "123.12" 2 decimal-places ] unit-test
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[ "123.123" ] [ "123.123" 5 decimal-places ] unit-test
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[ "123" ] [ "123.123" 0 decimal-places ] unit-test
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