ctags-lang-sql - Man Page

ctags ... [--extras={guest}] --languages=+SQL ...

The SQL parser supports various SQL dialects. PostgreSQL is one of them.

PostgreSQL allows user-defined functions to be written in other languages (procedural languages) besides SQL and C [PL].

The SQL parser makes tags for language objects in the user-defined functions written in the procedural languages if the guest extra is enabled.

The SQL parser looks for a token coming after LANGUAGE keyword in the source code to choose a proper guest parser.

... LANGUAGE plpythonu AS '... user-defined function ' ...
... AS $$ user-defined function $$ LANGUAGE plv8 ...

In the above examples, plpythonu and plv8 are the names of procedural languages. The SQL parser trims pl at the start and u at the end of the name before finding a ctags parser.  For plpythonu and plv8, the SQL parser extracts python and v8 as the candidates of guest parsers.

For plpythonu, ctags can run its Python parser.  ctags doesn't have a parser named v8. However, the JavaScript parser in ctags has v8 as an alias. So ctags can run the JavaScript parser as the guest parser for plv8.

tagging code including a user-defined function in a string literal [GH3006]:

"input.sql"

CREATE OR REPLACE FUNCTION fun1() RETURNS VARCHAR AS '
DECLARE
        test1_var1 VARCHAR(64) := $$ABC$$;
        test1_var2 VARCHAR(64) := $xyz$XYZ$xyz$;
        test1_var3     INTEGER := 1;
BEGIN
        RETURN  TO_CHAR(test_var3, ''000'') || test1_var1 || test1_var2;
END;
' LANGUAGE plpgsql;

"output.tags" with "--options=NONE -o - --sort=no --extras=+{guest} input.sql"

fun1    input.sql       /^CREATE OR REPLACE FUNCTION fun1() RETURNS VARCHAR AS '$/;"    f
test1_var1      input.sql       /^      test1_var1 VARCHAR(64) := $$ABC$$;$/;"  v
test1_var2      input.sql       /^      test1_var2 VARCHAR(64) := $xyz$XYZ$xyz$;$/;"    v
test1_var3      input.sql       /^      test1_var3     INTEGER := 1;$/;"        v

tagging code including a user-defined function in a dollar quote [GH3006]:

"input.sql"

CREATE OR REPLACE FUNCTION fun2() RETURNS VARCHAR LANGUAGE plpgsql AS $$
DECLARE
        test2_var1 VARCHAR(64) := 'ABC2';
        test2_var2 VARCHAR(64) := 'XYZ2';
        test2_var3        INTEGER := 2;
BEGIN
        RETURN  TO_CHAR(test2_var3, '000') || test2_var1 || test2_var2;
END;
$$;

"output.tags" with "--options=NONE -o - --sort=no --extras=+{guest} input.sql"

fun2    input.sql       /^CREATE OR REPLACE FUNCTION fun2() RETURNS VARCHAR LANGUAGE plpgsql AS $\$$/;" f
test2_var1      input.sql       /^      test2_var1 VARCHAR(64) := 'ABC2';$/;"   v
test2_var2      input.sql       /^      test2_var2 VARCHAR(64) := 'XYZ2';$/;"   v
test2_var3      input.sql       /^      test2_var3        INTEGER := 2;$/;"     v

tagging code including a user-defined written in JavaScript:

-- Derived from https://github.com/plv8/plv8/blob/r3.0alpha/sql/plv8.sql
CREATE FUNCTION test(keys text[], vals text[]) RETURNS text AS
$$
        var o = {};
        for (var i = 0; i < keys.length; i++)
                o[keys[i]] = vals[i];
        return JSON.stringify(o);
$$
LANGUAGE plv8 IMMUTABLE STRICT;

"output.tags" with "--options=NONE -o - --sort=no --extras=+{guest} input.sql"

test    input.sql       /^CREATE FUNCTION test(keys text[], vals text[]) RETURNS text AS$/;"    f
o       input.sql       /^      var o = {};$/;" v

Escape sequences ('') in a string literal may make a guest parser confused.

ctags(1), ctags-client-tools(7)

[PL]

PostgreSQL 9.5.25 Documentation, "Chapter 39. Procedural Languages", https://www.postgresql.org/docs/9.5/xplang.html

[GH3006]

@bagl's comment submitted to https://github.com/universal-ctags/ctags/issues/3006