Hi, Freeman Gilmore <freeman.gilm...@gmail.com> writes:
> On Sun, Dec 16, 2018 at 3:15 AM Mark H Weaver <m...@netris.org> wrote: > > Freeman Gilmore <freeman.gilm...@gmail.com> writes: > > > I am looking for a procedure that will read the numeric value, field 8, of > > an Unicode numeric character. Has anyone written this procedure or know > > where I can find it? > > The 'r7rs-wip' branch of the Guile git repository contains a procedure > that does this, with a lookup table derived from Unicode 6.3.0. > > > https://git.savannah.gnu.org/cgit/guile.git/tree/module/scheme/char.scm?h=r7rs-wip > > The file is written as an R7RS library form, which won't work on current > releases of Guile, but for now you could simply extract the > 'digit-value' procedure from it, provided that you preserve the > copyright notice. > > Mark > > Thank you Mark: > > That is only half the battle, let me explain. I do not want to read > the standard Unicode table. I want to directly read field 8 of a > numeric character in the privet use area of the Unicode. > > This is not part of scheme. The other half, I need to finger out how > to put the numeric values in field 8 for the characters I want to use. If the mapping from code points to numeric values is static, then you could simply modify the lookup table in the code I suggested above. If the mapping is dynamic, then you'll need a different strategy. One simple approach would be to use a hash table mapping from characters to digit values: (define digit-value-table (make-hash-table)) (define (set-digit-value! char value) (hashv-set! digit-value-table char value)) (define (digit-value char) (hashv-ref digit-value-table char #f)) If the range of relevant code points is small enough, another approach would be to use a vector: (define private-code-point-start #xE000) (define private-code-point-end #xF900) (define (code-point-in-range? cp) (<= private-code-point-start cp private-code-point-end)) (define digit-value-table (make-vector (- private-code-point-end private-code-point-start) #f)) (define (set-digit-value! char value) (let ((cp (char->integer char))) (unless (code-point-in-range? cp) (error "set-digit-value!: code point out of range:" cp)) (vector-set! digit-value-table (- cp private-code-point-start) value))) (define (digit-value char) (let ((cp (char->integer char))) (and (code-point-in-range? cp) (vector-ref digit-value-table (- cp private-code-point-start))))) For a more compact representation, you could use a SRFI-4 homogeneous numeric vector instead, although you'd need to designate a special numeric value to represent "not a digit". Regards, Mark