Greetings,
Sorry for the delayed response.
On Feb 4, 2009, at 4:11 AM, David Wingate wrote:
...
When I attempt to serialize my structure, it gives the following
error:
(serialize foodata)
Unhandled exception
Condition components:
1. &assertion
2. &who: fasl-write
3. &message: "Cannot write a non-thunk procedure; the one given has
free vars"
4. &irritants: (2)
I imagine this is NOT an error in Ikarus, but rather an error in my
thinking.
Could someone help me understand what generates this sort of error?
The fasl format in Ikarus is used primarily for serializing and
deserializing Ikarus's own data structures (primarily, compiled
library files). It has some limitations on what it can or cannot
handle. Serializing closures, continuations, system stacks, ports,
sockets, etc., are all problematic and never occur when serializing
compiled libraries (unless you're doing "too clever" things with
macros). You pretty much would be safe using it as long as
procedures (and continuations, and guardians, and general hash
tables, etc.) don't exist in the data structure you're trying to
serialize.
Now, there is a limitation in the implementation that fasl-write
allows writing procedures that have 0 lexical free variables (after
optimization), but disallows writing procedures that have any lexical
free variables. (I think it should disallow these in user code in
order to avoid this confusion.) I recommend that you don't rely on
this feature and only depend on serializing data structures that have
known structures (e.g., pairs, vectors, strings, records, chars,
numbers, booleans, (), etc.). This way, you'd keep your program more
portable by not depending on implementation-specific features.
Aziz,,,
