Syntax of Oberon-00, expressed in EBNF

ident  =  letter {letter | digit}.
integer  =  digit {digit}.
factor  =  ident | integer | "TRUE" | "FALSE" | "~" factor | "ODD" factor |
  "(" expression ")" | "{" expression ":" expression "," expression "}".
term  =  factor {("*" | "/" | "&") factor}.
SimpleExpression  =  ["+"|"-"] term {("+"| "-" | "OR") term}.
expression  =  SimpleExpression [("=" | "#" | "<" | ">=" | "<=" | ">") SimpleExpression].
assignment  =  ident ":=" expression {"," ident ":=" expression}.
IfStatement  =  "IF" expression "THEN" StatementSequence ["ELSE" StatementSequence] "END".
WhileStatement  =  "WHILE" expression "DO" StatementSequence "END".
Statement  =  [assignment | IfStatement | WhileStatement].
StatementSequence  =  Statement {";" Statement}.
type  =  "BOOLEAN" | "INTEGER".
IdentList  =  ident {"," ident} ":" type.
declarations  =  ["CONST" {IdentList ";"}] "VAR" {IdentList ";"}.
module  =  "MODULE" ident ";" declarations
  "BEGIN" StatementSequence "END" ident "." .