Usage of Polaris with Delta

Polaris may be used interactively from the Delta system. Each Polaris function which we desire to use from Delta must have an interface routine set up in a special way to communicate with Delta. It is suggested that the routine names be of the form: <function>_pu(). The following example shows how to write a Polaris routine which writes the Fortran form of the program to ``cout'', and is usable from Delta:

extern "C" int 
write_pu(char **data, int *len)
{
    P_ASSERT_HANDLER(0);
    external_interface_init();
 
    ProgramUnit *pgm = external_program_unit( data, len );
    p_assert( pgm, "not a program" );
 
    pgm->write( cout );
 
    return setup_to_return_handle( pgm->pu_tag_ref(), data, len);
}

The next example shows how to pass arguments from Delta to Polaris in addition to passing the program. The current Delta-Polaris interface converts all of the extra arguments to strings. It is up to the routine to covert then back into whatever they should be.

extern "C" int 
unroll_loop_pu(char **data, int *len)
{
    P_ASSERT_HANDLER(0);
    external_interface_init();
 
    List<StringElem> args;
 
    ProgramUnit *pgm = external_program_unit( data, len, args );
    p_assert( pgm, "not a valid ProgramUnit" );
 
    if (args.entries() == 2) {
        Statement *s1 = pgm->stmts().find_ref( args[0] );
        p_assert(s1 && s1->stmt_class() == DO_STMT, "statement is not a loop");
 
        int count = string_to_integer( args[1] );
        p_assert( count > 0, "number of iterations must be positive" );
        unroll_loop( *pgm, *s1, count );
    }
 
    return setup_to_return_handle( pgm->pu_tag_ref(), data, len);
}