Integers

Integers are digit sequences, which depending on the prefix, allow different characters. The digit sequences must be at least one digit long (prefix excluded).

Decimal integers, which don't have a prefix, but cannot start with 0. They use the decimal digits. Example:

0
100
44
// but not: 0

Hexidecimal integers (base 16) start with the prefix '0x'. They use decimal digits and the letters A - F, both lowercase and uppercase. Example:

0xFF
0x10
0xFA1
// but not: 0x

Octal integers (base 8) start with the prefix '0o'. The use the digits 0 - 7. Example:

0o1
0o71
// but not: 0o

To further denote the data type of the integer, suffixes are used. If no suffix is used the data type is int32.

u: Can be front of the suffixes s, S, l and L. Denotes that the data type is unsigned.
s: Very short. Data type is i8 or u8 if preceeded by u.
S: Short. Data type is i16 or u16 if preceeded by u.
l: long. Data type is i32 or u32 if preceeded by u.
L: Very long. Data type is i64 or u64 if preceeded by u.

All other letters are invalid, resulting in an error. So

0z
0h
0j

are considered invalid. Also letters after the suffix are invalid. Therefore

0ula
0la
100sD

are all invalid.