Whitespace 	= " " | "\t" .
Newline		= "\n" .
Digit		= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" .
Letter		= "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J" | "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z" |
                  "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" | "j" | "k" | "l" | "m" | "n" | "o" | "p" | "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" | "y" | "z".
AlNum           = Digit | Letter .
Num		= Digit { Digit } .
Name		= Letter { AlNum } .
Variable	= Name .
Function	= "(" Name ")" .
Ident		= Variable | Function .
Expression	= Term { ( "+" | "-" ) Term } .
Term		= Factor { ( "*" | "/" ) Factor } .
Factor		= Num | "(" Expression ")" | Ident .
Assignment	= Variable "=" Expression .
Condition	= Variable .
IfStatement	= "i" Condition Block "e" .
Statement	= { Assignment | IfStatement } Newline .
Block		= { Statement } .
Program		= Block "e" .