# Sequences

A sequence is zero or more comma separated items enclosed by
parentheses. Since they are enclosed by parentheses, sequences can be
passed to macros as single arguments making them an important unit of
encapsulation in this domain.

```{warning}
Some sequence macros may be limited to 30 items.
```

```{doxygendefine} CORE_PP_IS_SEQ
```

```{doxygendefine} CORE_PP_HEAD_SEQ
```

```{doxygendefine} CORE_PP_REST_SEQ
```

```{doxygendefine} CORE_PP_SECOND_SEQ
```

```{doxygendefine} CORE_PP_THIRD_SEQ
```

```{doxygendefine} CORE_PP_COUNT_SEQ
```

```{doxygendefine} CORE_PP_HEAD_LIST_OR_SEQ
```