There are several type of constant expression supported in evolve.
'A' Character value allows you to set a variable to a character value '\n' newline and '\r' carriage return can be used.
"String" A string is defined inside a set of inverted commas.
0x23ad The '0x' denoted that the value following is a hexadecimal number.
0b1010 The '0b' denotes that the number following is i binary format.
There are also special constants used for specific commands these are all capital letters and are pre fixed with a #. e.g. #RIGHT