Numbers

All numbers in Gab are IEEE 754 64-bit floating point values. There is no distinct integer type.

1
-42
1.2e4
0.2

3.14?   # => gab\number

Numbers less than one require a leading zero: 0.5, not .5. A bare . is the empty message send in Gab.

Arithmetic

The standard arithmetic operators are all message sends:

10 + 3   # => 13
10 - 3   # => 7
10 * 3   # => 30
10 / 3   # => 3.33333
10 % 3   # => 1

Bitwise Operations and 52-bit Integers

For bitwise operations, Gab uses 52-bit integers. This is because 64-bit floats can only represent integers losslessly up to 2^52. Limiting integers to 52 bits guarantees that Gab can convert freely between its float representation and integer operations without loss.

1 << 52   # => -4.5036e+15
1 << 53   # => 0

The standard bitwise operators:

4 & 6    # => 4   (AND)
4 | 2    # => 6   (OR)
4 << 1   # => 8   (left shift)
4 >> 1   # => 2   (right shift)

Bit-Shifting Edge Cases

Gab defines behaviour for several cases that are undefined or implementation-defined in C.

Shifting by a negative amount is treated as a shift in the opposite direction:

4 >> -1   # => 8
4 << -1   # => 2

Shifting by more than 52 returns zero:

4 >> 65   # => 0
4 << 65   # => 0

Shifting negative integers follows Lua’s semantics: the shift is performed on the unsigned bit representation, then converted back. This means right-shifting a negative number does not preserve the sign bit — it produces a large positive number:

-4 >> 1   # => 9223372036854775806
-4 << 1   # => -8

This is asymmetric but is the most efficient implementation, and shifting negative integers is uncommon enough that the trade-off is worthwhile.