psql_splitter
a nom parser combinator that matches a psql statement.
Postgres has a dialect of SQL that I'm going to call pgsql.
Postgres also has a client, psql, which recognizes meta-commands and inline-copy syntax that normal pgsql does not.
This parser recognizes psql meta-commands and pgsql tokens, allowing the statement combinator to know when a statement has ended.
The statement combinator also attaches color commentary on the end of a line to the previous statement, so select 1; -- take a number is matched as one statement.
Status
This is a hack with some tests, a README, and a license.
This parser doesn't understand all the tokens in pgsql and psql, which has its pros:
psql_splitter::statementis more likely to split statements out of invalid psql- a simpler parser is easier to maintain
but also its cons:
- a simpler parser is more likely to be missing something about the enormous pgsql language
Scope/features
- the splitter should match invalid psql, always splitting the input into one or more statements
- the splitter should treat psql meta-commands as statement terminators, e.g
select 1 as foo \gsetand\d my_tablewould both be complete statements. - the splitter should ignore statement-terminators inside pgsql strings and parentheses and exotic psql such as
\if ... \endifandCOPY table_name FROM STDIN; ... \. - the splitter should somewhat-reliably split psql and pgsql statements as defined by postgres, but not neccessarily other sql-like dialects derived from postgres's psql and pgsql.
- the splitter should be correct. Speed, a small binary, and memory efficiency aren't goals, but they're nice to have.
Contributing
If you find a bug, please submit an issue with a reproduction case. PRs for tooling would also be welcome.
License
While this library is offered under the attached BSD 3-clause at ./LICENSE, ./src/*.sql are excerpts from the postgres codebase, and so are covered by the postgres license.
Prior art
libpg_query's split_with_scanner
codeschool/sqlite-parser's test-suite-extraction tools