```"The string representation of the given [[integer]] in the
base given by [[radix]]. If the given integer is negative,
the string representation will begin with `-`. Digits
consist of decimal digits `0` to `9`, together with and
lowercase letters `a` to `z` for bases greater than 10.

For example:

- `formatInteger(-46)` is `\"-46\"`
- `formatInteger(9,2)` is `\"1001\"`
- `formatInteger(10,8)` is `\"12\"`
- `formatInteger(511,16)` is `\"1ff\"`
- `formatInteger(512,32)` is `\"g0\"`"
throws (`class AssertionError`,
see (`function parseInteger`)
shared String formatInteger(
"The integer value to format."
Integer integer,
inclusive."
if (integer == 0) {
return "0";
}
variable {Character*} digits = {};
variable Integer i = integer < 0
then integer
else -integer;
while (i != 0) {
Integer d = -(i % radix);
Character c;
if (0<=d<10) {
c = (d+zeroInt).character;
}
else if (10<=d<36) {
c = (d-10+aIntLower).character;
}
else {
assert (false);
}
digits = digits.follow(c);
i = (i + d) / radix;
}
if (integer < 0) {
digits = digits.follow('-');
}
return String(digits);
}
```