I/O changes
===========

While many agents may be created, there is still only one set of hook
functions and I/O routines.  To manage the complexities of identifying
agents, the following data structures are used:

agent * soar_agent;      /* The current Soar agent */
agent * global_agent;    /* The Soar control or global agent */

and a macro: current_agent(x) Many globals and some variables local to files
have been moved into a struct termed agent.  There are approximately 200
fields in this struct and anyone with I/O code should check to see if any
globals have been moved into this struct.  All references to a field foo
should be made as current_agent(foo) so that you can pick up the data
relevant to the current agent.  E.g., any reference to lexeme would be
replaced with current_agent(lexeme). Reference soar_agent and global_agent
only as pointers and avoid dereferencing them to get fields of the agent
struct.  The reason for this is that the organization of records may change
and the macro current_agent will remain stable, while the access path to a
record field may not.

A list of globals affected in this way may be found in the file
"global_vars.c"