'Banana' is a simple object serialization protocol.
- Main Procedures -
(encode value [profile]) ==> byte-vector [procedure]
Turns a value into a byte-vector representing that value.
Generally, the 'none' profile is used (and PROFILE defaults to
PROFILE/NONE), and with that one can encode only integers
(positive, zero, and negative, and of any size), lists, strings,
and reals (*FIXME* Real number encoding and decoding doesn't
work right now -- I haven't a clue how to encode them in the
IEEE floating point format, which is what Banana requires).
Example:
(encode '(1 -1 ("hello")))
(not printed as byte-vectors would normally print; this is
just how Banana output is ordinarily shown)
==> 03 80 01 81 01 83 01 80 05 82 68 65 6c 6c 6c 6f
(decode input-port/string/byte-vector [profile]) [procedure]
==> value
Decodes the output of ENCODE, or reads similar output from an
input port, or processes a string similarly.
Example:
(decode (encode '(1 -1 ("hello"))))
==> (1 -1 ("hello"))
(etb? byte) [procedure]
==> boolean
Returns #T if BYTE > 127 (#x7f), #F if otherwise. BYTE must be
an exact integer.
- Exceptions -
banana-error <-- error [condition type]
Subtypes of BANANA-ERROR are raised whenever anything involving
Banana-ing goes wrong. The procedure that raised the error is
stored in each BANANA-ERROR condition, too, accessed by
BANANA-ERROR-CALLER.
(banana-error? value) [condition type predicate]
(banana-error-caller banana-error) ==> symbol [procedure]
Returns the name of the procedure that raised BANANA-ERROR.
banana:unknown-byte <-- banana-error [condition type]
Raised when DECODE encounters an element type byte (see the
Banana specification on http://twistedmatrix.com/ for what the
element type bytes are) that it can't find in the profile it was
passed.
(unknown-byte-error? value) [condition type predicate]
(unknown-byte-error-byte banana:unknown-byte) ==> byte [procedure]
Returns the byte that DECODE didn't recognize.
(unknown-byte-error-profile banana:unknown-byte) [procedure]
==> profile
Returns the profile that DECODE was searching through.
banana:unsupported-type <-- banana-error [condition type]
Raised when a profile's encoder doesn't know how to Banana a
value of a certain type.
(unsupported-type-error? value) [condition type predicate]
(unsupported-type-error-type banana:unsupported-type) [procedure]
==> string
Returns the name of the type that a profile's encoder didn't
support.
(unsupported-type-error-value banana:unsupported-type) [procedure]
==> value
Returns the value of that type that a profile's encoder didn't
support.
read-eof-error <-- read-error [condition type]
Raised when an EOF is reached and was not expected.
- Profiles -
Profiles are ways to extend the Banana protocol. See the Banana
specification for how they work in Banana.
:profile [record type]
Profiles are stored in instances of this. They have four
fields, accessed by similar names --
name -- profile-name
encoder -- profile-encoder
decoder-table -- profile-decoder-table
parent -- profile-parent
NAME is mainly for debugging purposes.
ENCODER should be a procedure of one argument and should return
a byte vector.
DECODER-TABLE is a table of element type bytes to procedures of
two arguments.
PARENT is either #F (indicating no parent) or a profile from
which another profile can inherit element type byte decoders and
such.
(make-profile string proc alist) [procedure]
Makes a profile, whose name is STRING, whose encoder is PROC,
and whose decoder table is a table made from ALIST, which should
be a list of pairs, the CAR of each being an element type byte,
and the CDR of each being a decoder procedure.
(extend-profile profile string proc alist) [procedure]
The preferred profile constructor, this one allows you to make a
profile that inherits behaviour from another profile, but is
otherwise just like MAKE-PROFILE.
The BANANA-EXTRAS package includes a couple prettifying procedures
and a couple useful procedures should one desire to extend Banana.
(posint->byte-vector nonnegative-integer) [procedure]
The name is slightly misleading, since it also works on zero,
but in any case, it returns a byte vector of NONNEGATIVE-INTEGER
encoded as the Banana specification states. Note that it does
-not- produce a byte vector with the PROFILE/NONE element type
byte for nonnegative integers.
(byte-vector->posint byte-vector) [procedure]
The converse of POSINT->BYTE-VECTOR.
(prettify-byte byte) [procedure]
Makes BYTE look like it normally does when being described in
the context of Banana.
(prettify-byte-vector byte-vector) [procedure]
Returns a list of prettified bytes in BYTE-VECTOR.
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