offending token more efficiently (per your suggestion of using
scanbuf). The new patch does the same as before:

template1=# select * frum pg_class;
ERROR:  parser: parse error at or near "frum" at character 10

It also implement's Tom's suggestion:

template1=# select * from pg_class where\g
ERROR:  parse: parse error at end of input

Gavin Sherry