Constants

    const_dcl : 'const' const_type ID '=' const_exp
    const_type : integer_type | boolean_type | 
            floating_pt_type | 'string' 
            | type_name // must designate a simple type
    integer_type : [ 'unsigned' ] ( 'long' | 'short' )
    boolean_type : 'boolean'
    floating_pt_type : 'float' | 'double'
    const_exp : exp1 ( '|' exp1 )*
    exp1 : exp2 ( '^' exp2 )*
    exp2 : exp3 ( '&' exp3 )*
    exp3 : exp4 ( shift_op exp4 )*
    exp4 : exp5 ( add_op exp5 )*
    exp5 : exp6 ( mul_op exp6 )*
    exp6 : [ unary_op ] atom
    atom : const_name | literal | '(' const_exp ')'
    shift_op : '<<' | '>>'
    add_op : '+' | '-'
    mul_op : '*' | '/' | '%'
    unary_op : '+' | '-' | '~'
    literal :
        INTEGER_CONSTANT
        | STRING_LITERAL
        | CHARACTER_CONSTANT
        | FLOATING_CONSTANT
        | 'true' | 'false'
    const_name : scoped_name // must designate a const

A const_dcl binds a name to a simple (unstructured) constant value. Constants may be defined by C-like expressions involving literals and names of other constants. The type of the constant is explicitly indicated. An integer type must be explicitly indicated as long or short; there is no default integer size. Only one precision of floating point is supported.

Examples

    const long Kilobyte = 1<<10;
    const long Megabyte = 1<<20;
    const long BytesPerPage = 4*Kilobyte;
    const long MemSize = 20*Kilobyte;
    const long MaxPages = MemSize / BytesPerPage;
    const float PI = 3.1415926525;
    const float Avogadro = 6.02E24;
    const string Message = "Error";