D6: how to get one ctr from Richedit

I want to spell check words from a Richedit.Text but am having trouble 
in my GetWord routine. Here is the code. 

function GetWord(var p:integer):string;
{Get a word from Richedit1 starting at pos p.
Return changed p.
}
var s:string;
    c:char;
    i:integer;
begin
c:=midstr(Form1.Richedit1.text,p,1);
s:=''; //Beginning string
while (c in ['A'..'Z','a'..'z','-','1'..'0']) do //allowable ctrs.
    begin
    s:=s+c;
    inc(p);
    c:=midstr(Richedit1.text,p,1);
    end; //while
dec(p);
GetWord:=s;
end; //GetWord
{*******************************************************}
procedure TForm1.mnuSpell2Click(Sender: TObject);
var s:string;
    l,i,pos:integer;

begin
//Get a word, then check it.
pos:=0;
l:=length(Richedit1.text);
while (pos<l) do
    begin
    s:=GetWord(pos);
    if s=uppercase(s) then break; //Ignore all caps
    if ExecRegExpr('[0-9\.]+',s) then break; //Ignore all digits.
    if ExecRegExpr('[A-Z][a-z]+',s) then break; //Ignore initial capped 
words.
    if ExecRegExpr('[a-zA-Z]*[0-9]+[A-Za-z]*',s) then break; //Ignore 
words containing a digit. 
    janSpeller1.Spell(s);
    Richedit1.Seltext:=s;
    end;

end;

You will notice I want to skip certain types of words, so I have to 
check for those manually since my speller doesn't. But in GetWord, c is 
a char but midstr returns a string, thus I get a compile error (char 
and string incompatible or something). How do I get one char at a time 
from a Richedit1, while passing the current position pointer back from 
GetWord to mnuSpell2Click? 

Thanks.
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