Mark: I have been away and just getting back to email. Thank you for replying.
So it looks like the library is just a lookup table. I though it was more complicated than that, reading from a Unicode data file. The hash table may be better and more portable. I could also change the numeric value for the given code points as needed. I do not know what " SRFI-4 homogeneous numeric vector" is, but I did google it, a lot there. I am to new to this but I did copy your hash table that you made for me and added the correction. Thanks for your time here. I will probably be using it (if I learn enough). You all have a good year. ƒg On Mon, Dec 17, 2018 at 1:43 PM Mark H Weaver <m...@netris.org> wrote: > 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 >