  The determination of block-entropies is a well established method for the
investigation of discrete data, also called symbols (7). There is a large
variety of such symbolic sequences, ranging from texts written in natural
languages, computer programs, neural spike trains, and biosequences. In this
paper a new algorithm to construct a short context-free grammar (also called
program or description) that generates a given sequence is introduced. It
follows the general lines of a former algorithm, employed to compress
biosequences (1,2) and to estimate the complexity of neural spike trains (4),
which uses as valuation function the, so called, grammar complexity (2). The
new algorithm employs the (observed) block-entropies instead. A variant, which
employs a corrected "observed entropy", as discussed in (7) is also described.
To illustrate its usefulness, applications of the program to the syntactic
analysis of a sample biological sequences (DNA and RNA) is presented.
