> # Excerpts from a MUG posting
> #
> #From: "John B. Cosgrave" <johnbcos@iol.ie>
> #
> #I would like to thank all those who offered help in connection with my
> #recent question about enlarging the 'to_number' and 'from_number' procedures
> #in the Maple worksheet 'encrypt.ms' (which is in the examples directory of
> #MapleV - Release3). Some helpers communicated with me directly, and others through
> #the Maple Users Group. 
> #
> #I hope none of those who communicated with me will be
> #offended by my recording that the most helpful reply that I received was
> #from Joe Riel (somewhere in California) who directly sent me the following
> #invaluable (for me) reply, which I would like to share with other members of
> #the Maple Users Group:
> #
> #
> #Dear John (somewhere in Ireland, I presume),
> #
> #A simple solution to your problem is to unalias I, that is, execute
> #the command alias(I=I) before loading the procedures.  A better solution,
> #in my opinion, is to rewrite the procedures to use a global alphabet.
> #Here is my modification.
> #
> #You will want to modify the alphabet to be whatever is appropriate.
> #Note that the backquote is doubled, also there is no backslash.
> #
> `crypt/alphabet` := `abcdefghijklmnopqrstuvwxyz`
>                    .`ABCDEFGHIJKLMNOPQRSTUVWXYZ`
>                    .```1234567890-=~!@#$%^&*()_+`
>                    .` ,./<?;':"[]{}|`:
> 
> to_number := proc(st::string)
> local ll,nn,ss,ii;
> global `crypt/alphabet`;
>     ll := length(st);
>     if ll = 0 then RETURN(0) fi;
>     nn := 1;
>     for ii to ll do
>         ss := SearchText(substring(st,ii .. ii),`crypt/alphabet`);
>         if not type(ss,numeric) or ss = 0 then
>             ERROR(`the letter `.(substring(st,ii .. ii))
>                   .` is not in the alphabet`)
>         fi;
>         nn := 100*nn+ss
>     od;
>     nn-10^(2*ll)
> end:
> 
> from_number := proc(nn::integer)
> local ss,mm,ll,pp,ii,ans;
> global `crypt/alphabet`;
>     mm := nn;
>     ll := floor(1/2*trunc(evalf(log10(mm))))+1;
>     ans := ``;
>     for ii to ll do
>         mm := mm/100;
>         pp := 100*frac(mm);
>         if pp  length(`crypt/alphabet`) then
>             ERROR(`there is no letter in the alphabet corresponding to `
>                  .`the number `.(convert(pp,string))) fi;
>         ss := substring(`crypt/alphabet`, pp..pp);
>         ans := cat(ss,ans);
>         mm := trunc(mm)
>     od;
>     ans
> end:
> #
> #Joe Riel
> #
> #
> #Thanking you all once again,
> #
> #John Cosgrave,
> #Mathematics Department,
> #St.Patrick's College,
> #Drumcondra,
> #Dublin 9,
> #Ireland.
> #
> #P.S. We are all still surviving there without e-mail. I am contemplating
> #suggesting to my College's Administration that we should consider turning
> #our disadvantage to our advantage by turning the College into a
> #"theme-park". We could advertise holidays there for school children, with
> #slogans like: 
> #Visit St.Patrick's!! Why bother using your CD-ROM to see crude pictures of
> #dinosaurs? Why not see some real dinosaurs, and even talk to them!! ... .