plpgsql trigger parse error - Mailing list pgsql-general

I am having trouble getting a pl/PgSQL function to parse correctly and
my usual divide and conquer strategy is not working very well.  The
full function appears at the bottom.  When I simplified it to only the
first if (...) clause, it works.  When I added the first else if (...)
clause, as shown immediately below, it fails.

create function deepsky_nodups() returns opaque as '
    begin
        if (NEW.suffix is NULL and NEW.component is NULL) then
            if (exists (select id from deepsky where catalog = NEW.catalog and entry = NEW.entry and suffix is null and
componentis null)) then 
                return NULL;
            end if;
        else if (NEW.component is NULL) then
            if (exists (select id from deepsky where catalog = NEW.catalog and entry = NEW.entry and suffix =
NEW.suffixand component is null)) then 
                return NULL;
            end if
        end if;
        return NEW;
    end;
' language 'plpgsql';

create trigger ds_nodups before insert on deepsky
   for each row execute procedure deepsky_nodups();

When it fires via the following insert

    insert into deepsky (catalog, entry) values ('NGC', '1');

I get this error

NOTICE:  plpgsql: ERROR during compile of deepsky_nodups near line 6
ERROR:  parse error at or near "else"

I've stared at this so long I've run out of ideas on what might be
wrong.  I started by cutting it down to the first if (...) and exists
clause.  That works fine, i.e.,

create function deepsky_nodups() returns opaque as '
    begin
        if (NEW.suffix is NULL and NEW.component is NULL) then
            if (exists (select id from deepsky where catalog = NEW.catalog and entry = NEW.entry and suffix is null and
componentis null)) then 
                return NULL;
            end if;
        end if;
        return NEW;
    end;
' language 'plpgsql';

is fine.  The full function gives me a different error,

NOTICE:  plpgsql: ERROR during compile of deepsky_nodups near line 20
ERROR:  parse error at or near ";"

Here is the full function:

create function deepsky_nodups() returns opaque as '
    begin
        if (NEW.suffix is NULL and NEW.component is NULL) then
            if (exists (select id from deepsky where catalog = NEW.catalog and entry = NEW.entry and suffix is null and
componentis null)) then 
                return NULL;
            end if;
        else if (NEW.component is NULL) then
            if (exists (select id from deepsky where catalog = NEW.catalog and entry = NEW.entry and suffix =
NEW.suffixand component is null)) then 
                return NULL;
            end if;
        else if (NEW.suffix is NULL) then
            if (exists (select id from deepsky where catalog = NEW.catalog and entry = NEW.entry and component =
NEW.componentand suffix is null)) then 
                return NULL;
            end if;
        else
            if (exists (select id from deepsky where catalog = NEW.catalog and entry = NEW.entry and component =
NEW.componentand suffix = NEW.suffix)) then 
                return NULL;
            end if;
        end if;
        return NEW;
    end;
' language 'plpgsql';

What am I missing?

roland
--
                       PGP Key ID: 66 BC 3B CD
Roland B. Roberts, PhD                             RL Enterprises
roland@rlenter.com                     76-15 113th Street, Apt 3B
roland@astrofoto.org                       Forest Hills, NY 11375