Pangram checker

You are encouraged to solve this task according to the task description, using any language you may know.
A pangram is a sentence that contains all the letters of the English alphabet at least once.

For example:   The quick brown fox jumps over the lazy dog.



Task

Write a function or method to check a sentence to see if it is a   pangram   (or not)   and show its use.



Related tasks

   determine if a string has all the same characters
   determine if a string has all unique characters


proc nonrec pangram(*char s) bool:
    ulong letters;
    char c;
    byte b;
    byte A = pretend('a', byte);
    byte Z = pretend('z', byte);
 
    letters := 0L0;
    while
        c := s*;
        s := s + 1;
        c /= '\e'
    do
        b := pretend(c, byte) | 32;
        if b >= A and b <= Z then
            letters := letters | 0L1 << (b-A)
        fi
    od;
    letters = 0x3FFFFFF
corp
 
proc nonrec test(*char s) void:
    writeln("\"", s, "\": ", 
            if pangram(s) then "yes" else "no" fi)
corp
 
proc nonrec main() void:
    test("The quick brown fox jumps over the lazy dog.");
    test("The five boxing wizards jump quickly.");
    test("Not a pangram")
corp