úÎnä  1(c) Daan Leijen 1999-2001, (c) Paolo Martini 2007 BSD-style (see the LICENSE file)NoneAn  OperatorTable is a list of Operator• lists. The list is ordered in descending precedence. All operators in one list have the same precedence (but may have a different associativity).?This data type specifies operators that work on values of type az. An operator is either binary infix or unary prefix or postfix. A binary operator has also an associated associativity.NThis data type specifies the associativity of operators: left, right or none.  buildExpressionParser table term( builds an expression parser for terms term with operators from table8, taking the associativity and precedence specified in table^ into account. Prefix and postfix operators of the same precedence can only occur once (i.e. --2 is not allowed if -h is prefix negate). Prefix and postfix operators of the same precedence associate to the left (i.e. if ++ is postfix increment, than -2++ equals -1, not -3).The buildExpressionParserº takes care of all the complexity involved in building expression parser. Here is an example of an expression parser that handles prefix signs, postfix increment and basic arithmetic. ÿ^ expr = buildExpressionParser table term <?> "expression" term = parens expr <|> natural <?> "simple expression" table = [ [prefix "-" negate, prefix "+" id ] , [postfix "++" (+1)] , [binary "*" (*) AssocLeft, binary "/" (div) AssocLeft ] , [binary "+" (+) AssocLeft, binary "-" (-) AssocLeft ] ] binary name fun assoc = Infix (do{ reservedOp name; return fun }) assoc prefix name fun = Prefix (do{ reservedOp name; return fun }) postfix name fun = Postfix (do{ reservedOp name; return fun })        attoparsec-expr-0.1.1.2Data.Attoparsec.Expr OperatorTableOperatorPostfixPrefixInfixAssoc AssocRight AssocLeft AssocNonebuildExpressionParser