Data Representation - Specifying Minimum Size

From Rosetta Code

Demonstrate how to specify the minimum size of a variable or a data type.

[edit] Ada

type Response is (Yes, No); -- Definition of an enumeration type with two values
for Response'Size use 1; -- Setting the size of Response to 1 bit, rather than the default single byte size

[edit] D

In D, any variables of static array of zero length has a size of zero. But such data is useless, as no base type element can be accessed.

typedef long[0] zeroLength ; 
writefln(zeroLength.sizeof) ; // print 0 

NOTE: a dynamic array variable's size is always 8 bytes, 4(32-bit) for length and 4 for a reference pointer of the actual storage somewhere in runtime memory.
The proper candidates of minimum size variable are empty structure, 1-byte size data type variable (include byte, ubyte, char and bool), and void, they all occupy 1 byte.

byte b ;
ubyte ub ;
char c ;
bool t ;

bool is logically 1-bit size, but it actually occupy 1 byte.
void can't be declared alone, but void.sizeof gives 1.
An empty structure is logically zero size, but still occupy 1 byte.

struct Empty { }
writefln(Empty.sizeof) ; // print 1

[edit] Perl

I suppose you could use vec() or similar to twiddle a single bit. The thing is, as soon as you store this in a variable, the SV (the underlying C implementation of the most simple data type) already takes a couple dozen of bytes.

In Perl, memory is readily and happily traded for expressiveness and ease of use.