# compose

## Description:

Performs a single composition step of the Unicode canonical composition algorithm.

This function includes algorithmic Hangul Jamo composition, but it is not exactly the inverse of
decompose. No composition can have either of `a`

or `b`

equal to zero. To be precise, this function composes if and only if there exists a Primary Composite P which is canonically equivalent to the
sequence <`a`

,`b`

>. See the Unicode Standard for the definition of Primary Composite.

If `a`

and `b`

do not compose a new character, `ch`

is set to zero.

See UAX#15 for details.

## Parameters:

b |
a Unicode character |

ch |
return location for the composed character |

a |
a Unicode character |

## Returns:

true if the characters could be composed |