See region.h

Plash has some functions for handling strings of bytes, which are used for text and binary data. There are facilities for constructing strings, and decomposing strings.

The seqf_t type ("flat sequence") is a struct which represents a string stored contiguously in memory.

The seqt_t type ("tree sequence") represents a string that need not stored contiguously. It is a tree structure containing strings to be concatenated together.

You can concatenate seqt_ts using the functions cat2, cat3, cat4, etc. These all use a region to allocate nodes.

The flatten function turns a seqt_t into a seqf_t.