Tokenised
alphabet and grammar
If
you type cmd-h with the 'option' key down you have the option to display the
alphabet in its "tokenised" form. A
tokenised
alphabet/grammar/glossar
y
is useful to show whatever the compiler has been able to understand. It is
displayed in a multi-purpose window called the "Trace" window.
Fig.11
Tokenised
alphabet
in the "Trace" window The
tokenised alphabet actually displays the entire mapping of
homomorphism
notated '
*'
that was partly defined in the original alphabet (see §2.4). Predefined
symbols '-' and '_' represent
silences
and
prolongations
respectively. These are not modified by any homomorphism. Other symbols are
specific to this "-ho.abc1" alphabet. Homomorphism '
*'
changes 'a' to 'a'', but 'a'' remains unchanged. Symbol 'chik' is also not
affected by the transformation. (See §2.4 or reference manual §4.1
to understand homomorphisms.)
Looking
carefully at the alphabet you may notice that a new terminal symbol 'sync' has
been appended: it was not in the original file "-ho.abc1". The symbol was
actually found between single quotes in the grammar, and therefore appended at
compile time. Similarly, out-time sound-objec
ts
between angle brackets <<>> may contain terminal symbols that BP2
creates at compile time.
The
tokenised grammar is shown Fig.12.
Fig.12
Tokenised grammar
in "Trace" window All
rules have been numbered and contain
weights.
(See an explanation of weights in reference manual §4.6) Rules that were
not assigned explicit weights appear with default weight <127>, a value
that fits well with MIDI parameters.
Also
note that commentaries [between square brackets] or lines starting with double
slashes have been left out.
Rule
numberin
g
has no real effect on computation. For instance, the order in which rules are
scanned in "ORD" grammars (see reference manual §4.4) is always their
actual order of occurrence in the grammar. Nevertheless, BP2 renumbers
subgrammars and rules at compile time. These numbers are used for conditional
jump
s
found in
grammar
procedures
(see §8.1 of reference manual).