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_archive/rhai_engine/rhaibook/ref/numbers.md

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+Numbers
+=======
+
+
+Integers
+--------
+
+Integer numbers follow C-style format with support for decimal, binary (`0b`), octal (`0o`) and hex (`0x`) notations.
+
+Integers can also be conveniently manipulated as [bit-fields](bit-fields.md).
+
+
+Floating-Point Numbers
+----------------------
+
+Both decimal and scientific notations can be used to represent floating-point numbers.
+
+
+Decimal Numbers
+---------------
+
+When rounding errors cannot be accepted, such as in financial calculations, use the decimal type,
+which is a fixed-precision floating-point number with no rounding errors.
+
+
+Number Literals
+---------------
+
+`_` separators can be added freely and are ignored within a number – except at the very
+beginning or right after a decimal point (`.`).
+
+| Sample             | Format                    |
+| ------------------ | ------------------------- |
+| `_123`             | _improper separator_      |
+| `123_345`, `-42`   | decimal                   |
+| `0o07_76`          | octal                     |
+| `0xab_cd_ef`       | hex                       |
+| `0b0101_1001`      | binary                    |
+| `123._456`         | _improper separator_      |
+| `123_456.78_9`     | normal floating-point     |
+| `-42.`             | ending with decimal point |
+| `123_456_.789e-10` | scientific notation       |
+| `.456`             | _missing leading `0`_     |
+| `123.456e_10`      | _improper separator_      |
+| `123.e-10`         | _missing decimal `0`_     |
+
+
+Floating-Point vs. Decimal
+--------------------------
+
+Decimal numbers represents a fixed-precision floating-point number which is popular with financial
+calculations and other usage scenarios where round-off errors are not acceptable.
+
+Decimal numbers take up more space (16 bytes each) than a standard floating-point number (4-8 bytes)
+and is much slower in calculations due to the lack of CPU hardware support. Use it only when
+necessary.