The abstract type of buffers.

create n returns a fresh buffer, initially empty. The n parameter is the initial size of the internal byte sequence that holds the buffer contents. That byte sequence is automatically reallocated when more than n characters are stored in the buffer, but shrinks back to n characters when reset is called. For best performance, n should be of the same order of magnitude as the number of characters that are expected to be stored in the buffer (for instance, 80 for a buffer that holds one output line). Nothing bad will happen if the buffer grows beyond that limit, however. In doubt, take n = 16 for instance. If n is not between 1 and Sys.max_string_length, it will be clipped to that interval.

Return a copy of the current contents of the buffer. The buffer itself is unchanged.

add_char b c appends the character c at the end of buffer b.

Return the number of characters currently contained in the buffer.

add_string b s appends the string s at the end of buffer b.

add_substring b s ofs len takes len characters from offset ofs in string s and appends them at the end of buffer b.

add_subbytes b s ofs len takes len characters from offset ofs in byte sequence s and appends them at the end of buffer b.

• since 4.02

Get the n-th character of the buffer. Raise Invalid_argument if index out of bounds

Empty the buffer.

Empty the buffer and deallocate the internal byte sequence holding the buffer contents, replacing it with the initial internal byte sequence of length n that was allocated by Buffer.create n. For long-lived buffers that may have grown a lot, reset allows faster reclamation of the space used by the buffer.