| 1 | -- --------------------------------------------------------- |
| 2 | -- reader.sql |
| 3 | |
| 4 | CREATE SCHEMA reader; |
| 5 | |
| 6 | CREATE FUNCTION reader.tokenize(str varchar) RETURNS varchar[] AS $$ |
| 7 | DECLARE |
| 8 | re varchar = E'[[:space:] ,]*(~@|[\\[\\]{}()\'`~@]|"(?:[\\\\].|[^\\\\"])*"|;[^\n]*|[^\\s \\[\\]{}()\'"`~@,;]*)'; |
| 9 | BEGIN |
| 10 | RETURN ARRAY(SELECT tok FROM |
| 11 | (SELECT (regexp_matches(str, re, 'g'))[1] AS tok) AS x |
| 12 | WHERE tok <> '' AND tok NOT LIKE ';%'); |
| 13 | END; $$ LANGUAGE plpgsql IMMUTABLE; |
| 14 | |
| 15 | -- read_atom: |
| 16 | -- takes a tokens array and position |
| 17 | -- returns new position and value_id |
| 18 | CREATE FUNCTION reader.read_atom(tokens varchar[], |
| 19 | INOUT pos integer, OUT result integer) AS $$ |
| 20 | DECLARE |
| 21 | str_id integer; |
| 22 | str varchar; |
| 23 | token varchar; |
| 24 | BEGIN |
| 25 | token := tokens[pos]; |
| 26 | pos := pos + 1; |
| 27 | -- RAISE NOTICE 'read_atom: %', token; |
| 28 | IF token = 'nil' THEN -- nil |
| 29 | result := 0; |
| 30 | ELSIF token = 'false' THEN -- false |
| 31 | result := 1; |
| 32 | ELSIF token = 'true' THEN -- true |
| 33 | result := 2; |
| 34 | ELSIF token ~ '^-?[0-9][0-9]*$' THEN -- integer |
| 35 | -- integer |
| 36 | INSERT INTO types.value (type_id, val_int) |
| 37 | VALUES (3, CAST(token AS integer)) |
| 38 | RETURNING value_id INTO result; |
| 39 | ELSIF token ~ '^".*"' THEN -- string |
| 40 | -- string |
| 41 | str := substring(token FROM 2 FOR (char_length(token)-2)); |
| 42 | str := replace(str, '\"', '"'); |
| 43 | str := replace(str, '\n', E'\n'); |
| 44 | str := replace(str, '\\', E'\\'); |
| 45 | result := types._stringv(str); |
| 46 | ELSIF token ~ '^:.*' THEN -- keyword |
| 47 | -- keyword |
| 48 | result := types._keywordv(substring(token FROM 2 FOR (char_length(token)-1))); |
| 49 | ELSE |
| 50 | -- symbol |
| 51 | result := types._symbolv(token); |
| 52 | END IF; |
| 53 | END; $$ LANGUAGE plpgsql; |
| 54 | |
| 55 | -- read_seq: |
| 56 | -- takes a tokens array, type (8, 9, 10), first and last characters |
| 57 | -- and position |
| 58 | -- returns new position and value_id for a list (8), vector (9) or |
| 59 | -- hash-map (10) |
| 60 | CREATE FUNCTION reader.read_seq(tokens varchar[], first varchar, last varchar, |
| 61 | INOUT p integer, OUT items integer[]) AS $$ |
| 62 | DECLARE |
| 63 | token varchar; |
| 64 | key varchar = NULL; |
| 65 | item_id integer; |
| 66 | BEGIN |
| 67 | token := tokens[p]; |
| 68 | p := p + 1; |
| 69 | IF token <> first THEN |
| 70 | RAISE EXCEPTION 'expected ''%''', first; |
| 71 | END IF; |
| 72 | items := ARRAY[]::integer[]; |
| 73 | LOOP |
| 74 | IF p > array_length(tokens, 1) THEN |
| 75 | RAISE EXCEPTION 'expected ''%''', last; |
| 76 | END IF; |
| 77 | token := tokens[p]; |
| 78 | IF token = last THEN EXIT; END IF; |
| 79 | SELECT * FROM reader.read_form(tokens, p) INTO p, item_id; |
| 80 | items := array_append(items, item_id); |
| 81 | END LOOP; |
| 82 | |
| 83 | p := p + 1; |
| 84 | END; $$ LANGUAGE plpgsql; |
| 85 | |
| 86 | -- read_form: |
| 87 | -- takes a tokens array and position |
| 88 | -- returns new position and value_id |
| 89 | CREATE FUNCTION reader.read_form(tokens varchar[], |
| 90 | INOUT pos integer, OUT result integer) AS $$ |
| 91 | DECLARE |
| 92 | vid integer; |
| 93 | meta integer; |
| 94 | token varchar; |
| 95 | BEGIN |
| 96 | token := tokens[pos]; -- peek |
| 97 | CASE |
| 98 | WHEN token = '''' THEN |
| 99 | BEGIN |
| 100 | pos := pos + 1; |
| 101 | SELECT * FROM reader.read_form(tokens, pos) INTO pos, vid; |
| 102 | result := types._list(ARRAY[types._symbolv('quote'), vid]); |
| 103 | END; |
| 104 | WHEN token = '`' THEN |
| 105 | BEGIN |
| 106 | pos := pos + 1; |
| 107 | SELECT * FROM reader.read_form(tokens, pos) INTO pos, vid; |
| 108 | result := types._list(ARRAY[types._symbolv('quasiquote'), vid]); |
| 109 | END; |
| 110 | WHEN token = '~' THEN |
| 111 | BEGIN |
| 112 | pos := pos + 1; |
| 113 | SELECT * FROM reader.read_form(tokens, pos) INTO pos, vid; |
| 114 | result := types._list(ARRAY[types._symbolv('unquote'), vid]); |
| 115 | END; |
| 116 | WHEN token = '~@' THEN |
| 117 | BEGIN |
| 118 | pos := pos + 1; |
| 119 | SELECT * FROM reader.read_form(tokens, pos) INTO pos, vid; |
| 120 | result := types._list(ARRAY[types._symbolv('splice-unquote'), vid]); |
| 121 | END; |
| 122 | WHEN token = '^' THEN |
| 123 | BEGIN |
| 124 | pos := pos + 1; |
| 125 | SELECT * FROM reader.read_form(tokens, pos) INTO pos, meta; |
| 126 | SELECT * FROM reader.read_form(tokens, pos) INTO pos, vid; |
| 127 | result := types._list(ARRAY[types._symbolv('with-meta'), vid, meta]); |
| 128 | END; |
| 129 | WHEN token = '@' THEN |
| 130 | BEGIN |
| 131 | pos := pos + 1; |
| 132 | SELECT * FROM reader.read_form(tokens, pos) INTO pos, vid; |
| 133 | result := types._list(ARRAY[types._symbolv('deref'), vid]); |
| 134 | END; |
| 135 | |
| 136 | -- list |
| 137 | WHEN token = ')' THEN |
| 138 | RAISE EXCEPTION 'unexpected '')'''; |
| 139 | WHEN token = '(' THEN |
| 140 | BEGIN |
| 141 | SELECT p, types._list(items) |
| 142 | FROM reader.read_seq(tokens, '(', ')', pos) INTO pos, result; |
| 143 | END; |
| 144 | |
| 145 | -- vector |
| 146 | WHEN token = ']' THEN |
| 147 | RAISE EXCEPTION 'unexpected '']'''; |
| 148 | WHEN token = '[' THEN |
| 149 | BEGIN |
| 150 | SELECT p, types._vector(items) |
| 151 | FROM reader.read_seq(tokens, '[', ']', pos) INTO pos, result; |
| 152 | END; |
| 153 | |
| 154 | -- hash-map |
| 155 | WHEN token = '}' THEN |
| 156 | RAISE EXCEPTION 'unexpected ''}'''; |
| 157 | WHEN token = '{' THEN |
| 158 | BEGIN |
| 159 | SELECT p, types._hash_map(items) |
| 160 | FROM reader.read_seq(tokens, '{', '}', pos) INTO pos, result; |
| 161 | END; |
| 162 | |
| 163 | -- |
| 164 | ELSE |
| 165 | SELECT * FROM reader.read_atom(tokens, pos) INTO pos, result; |
| 166 | END CASE; |
| 167 | END; $$ LANGUAGE plpgsql; |
| 168 | |
| 169 | -- read_str: |
| 170 | -- takes a string |
| 171 | -- returns a new value_id |
| 172 | CREATE FUNCTION reader.read_str(str varchar) RETURNS integer AS $$ |
| 173 | DECLARE |
| 174 | tokens varchar[]; |
| 175 | pos integer; |
| 176 | ast integer; |
| 177 | BEGIN |
| 178 | tokens := reader.tokenize(str); |
| 179 | -- RAISE NOTICE 'read_str first: %', tokens[1]; |
| 180 | pos := 1; |
| 181 | SELECT * FROM reader.read_form(tokens, pos) INTO pos, ast; |
| 182 | -- RAISE NOTICE 'pos after read_atom: %', pos; |
| 183 | RETURN ast; |
| 184 | END; $$ LANGUAGE plpgsql; |
| 185 | |