thoughts on Avro code gen.c

// a GenAvro file might look like:

// @namespace("wwm")
record timestamp {
    long seconds;
    long nanoseconds;
}

// @namespace("wwm")
record something {
    string whatever;
}

// @namespace("wwm")
record lock_activity {
    timestamp timestamp;
    long lockID;
    array<something> foo;
}

/*
That'll generate at least these files:

 * wwm_types.h
 * wwm_types_read.c
 * wwm_types_read_template.i
 * wwm_types_size.c
 * wwm_types_size_template.i
 * wwm_types_skip.c
 * wwm_types_skip_template.i
 * wwm_types_write.c
 * wwm_types_write_template.i

wwm_types_write.c would look like:
*/

#define AVRO_ENCODE(NAMESPACE, TYPE) NAMESPACE ## _encode_ ## TYPE ## _binary
#include "wwm_types_write_template.i"
#undef AVRO_ENCODE

#define AVRO_ENCODE(NAMESPACE, TYPE) NAMESPACE ## _encode_ ## TYPE ## _json
#include "wwm_types_write_template.i"
#undef AVRO_ENCODE

/*
wwm_types_write_template.i would look like:
*/

int AVRO_ENCODE(wwm, timestamp)(avro_writer_t writer, wwm_timestamp_t * this)
{
    BEGIN_ENCODER;
    CHECK(AVRO_ENCODE(avro, long)(writer, this->seconds));
    CHECK(AVRO_ENCODE(avro, long)(writer, this->nanoseconds));
    return 0;
    HANDLE_ERROR;
}

int AVRO_ENCODE(wwm, something)(avro_writer_t writer, wwm_something_t * this)
{
    BEGIN_ENCODER;
    CHECK(AVRO_ENCODE(avro, string)(writer, this->whatever));
    return 0;
    HANDLE_ERROR;
}

int AVRO_ENCODE(wwm, lock_activity)(avro_writer_t writer, wwm_lock_activity * this)
{
    BEGIN_ENCODER;
    CHECK(AVRO_ENCODE(wwm, timestamp)(this->timestamp, writer));
    CHECK(AVRO_ENCODE(avro, long)(writer, this->lockID));
    CHECK(AVRO_ENCODE(avro, array_begin)(writer, this->foo_count));
    for (int idx = 0; idx < this->foo_count; idx++) {
        CHECK(AVRO_ENCODE(wwm, something)(writer, this->foos[idx]));
    }
    CHECK(AVRO_ENCODE(avro, array_end)(writer));
    return 0;
    HANDLE_ERROR;
}

/*
And some of the utility stuff there would be defined as:
*/

#define BEGIN_ENCODER int rval
#define CHECK(INVOCATION) rval = INVOCATION; if (rval != 0) goto handle_error;
#define HANDLE_ERROR handle_error: return rval;