grammar

BNF 語法

典型的語法範例

program: statement;
statement: whileStatement
        | ifStatement
        | // other statement possibilities ...
        | '{' statementSequence '}'
whileStatement: 'while' '(' expression ')' statement
ifStatement: simpleIf
        | ifElse
simpleIf: 'if' '(' expression ')' statement
ifElse: 'if' '(' expression ')' statement
        'else' statement
statementSequence: '' // null, i.e. the empty sequence
        | statement ';' statementSequence
expression: // definition of an expression comes here
        // more definitions follow