plpgsql/step2_eval.sql

   1 \i init.sql
   2 \i types.sql
   3 \i reader.sql
   4 \i printer.sql
   5
   6 -- ---------------------------------------------------------
   7 -- step1_read_print.sql
   8
   9 -- read
  10 CREATE OR REPLACE FUNCTION READ(line varchar) RETURNS integer AS $$
  11 BEGIN
  12     RETURN read_str(line);
  13 END; $$ LANGUAGE plpgsql;
  14
  15 -- eval
  16 CREATE OR REPLACE FUNCTION just_add(args integer[]) RETURNS integer AS $$
  17 BEGIN RETURN args[1] + args[2]; END; $$ LANGUAGE plpgsql;
  18
  19 CREATE OR REPLACE FUNCTION eval_ast(ast integer, env integer) RETURNS integer AS $$
  20 DECLARE
  21     type           integer;
  22     symkey         varchar;
  23     vid            integer;
  24     i              integer;
  25     src_coll_id    integer;
  26     dst_coll_id    integer = NULL;
  27     e              integer;
  28     result         integer;
  29 BEGIN
  30     SELECT type_id INTO type FROM value WHERE value_id = ast;
  31     CASE
  32     WHEN type = 7 THEN
  33     BEGIN
  34         symkey := _vstring(ast);
  35         SELECT e.value_id FROM env e INTO result
  36             WHERE e.env_id = env
  37             AND e.key = symkey;
  38         IF result IS NULL THEN
  39             RAISE EXCEPTION '''%'' not found', symkey;
  40         END IF;
  41     END;
  42     WHEN type = 8 OR type = 9 THEN
  43     BEGIN
  44         src_coll_id := (SELECT collection_id FROM value WHERE value_id = ast);
  45         FOR vid, i IN (SELECT value_id, idx FROM collection
  46                        WHERE collection_id = src_coll_id)
  47         LOOP
  48             e := EVAL(vid, env);
  49             IF dst_coll_id IS NULL THEN
  50                 dst_coll_id := COALESCE((SELECT Max(collection_id)
  51                                          FROM collection)+1,0);
  52             END IF;
  53             -- Evaluated each entry
  54             INSERT INTO collection (collection_id, idx, value_id)
  55                 VALUES (dst_coll_id, i, e);
  56         END LOOP;
  57         -- Create value entry pointing to new collection
  58         INSERT INTO value (type_id, collection_id)
  59             VALUES (type, dst_coll_id)
  60             RETURNING value_id INTO result;
  61     END;
  62     ELSE
  63         result := ast;
  64     END CASE;
  65
  66     RETURN result;
  67 END; $$ LANGUAGE plpgsql;
  68
  69 CREATE OR REPLACE FUNCTION EVAL(ast integer, env integer) RETURNS integer AS $$
  70 DECLARE
  71     type    integer;
  72     el      integer;
  73     fname   varchar;
  74     args    integer[];
  75     result  integer;
  76 BEGIN
  77     SELECT type_id INTO type FROM value WHERE value_id = ast;
  78     IF type <> 8 THEN
  79         RETURN eval_ast(ast, env);
  80     END IF;
  81
  82     el := eval_ast(ast, env);
  83     SELECT function_name INTO fname FROM value WHERE value_id = _first(el);
  84     args := _restArray(el);
  85     -- RAISE NOTICE 'fname: %, args: %', fname, args;
  86     EXECUTE format('SELECT %s($1);', fname)
  87         INTO result USING args;
  88     RETURN result;
  89 END; $$ LANGUAGE plpgsql;
  90
  91 -- print
  92 CREATE OR REPLACE FUNCTION PRINT(exp integer) RETURNS varchar AS $$
  93 BEGIN
  94     RETURN pr_str(exp);
  95 END; $$ LANGUAGE plpgsql;
  96
  97
  98 -- repl
  99
 100 -- env table
 101 CREATE TABLE env (
 102     env_id    integer NOT NULL,
 103     key       varchar NOT NULL,
 104     value_id  integer NOT NULL
 105 );
 106
 107 CREATE OR REPLACE FUNCTION env_vset(env integer, name varchar, val integer)
 108     RETURNS void AS $$
 109 BEGIN
 110     INSERT INTO env (env_id, key, value_id) VALUES (env, name, val);
 111 END; $$ LANGUAGE plpgsql;
 112
 113
 114 CREATE OR REPLACE FUNCTION mal_intop(op varchar, args integer[]) RETURNS integer AS $$
 115 DECLARE a integer; b integer; result integer;
 116 BEGIN
 117     SELECT val_int INTO a FROM value WHERE value_id = args[1];
 118     SELECT val_int INTO b FROM value WHERE value_id = args[2];
 119     EXECUTE format('INSERT INTO value (type_id, val_int) VALUES (3, $1 %s $2)
 120                     RETURNING value_id;', op) INTO result USING a, b;
 121     RETURN result;
 122 END; $$ LANGUAGE plpgsql;
 123
 124 CREATE OR REPLACE FUNCTION mal_add(args integer[]) RETURNS integer AS $$
 125 BEGIN RETURN mal_intop('+', args); END; $$ LANGUAGE plpgsql;
 126 CREATE OR REPLACE FUNCTION mal_subtract(args integer[]) RETURNS integer AS $$
 127 BEGIN RETURN mal_intop('-', args); END; $$ LANGUAGE plpgsql;
 128 CREATE OR REPLACE FUNCTION mal_multiply(args integer[]) RETURNS integer AS $$
 129 BEGIN RETURN mal_intop('*', args); END; $$ LANGUAGE plpgsql;
 130 CREATE OR REPLACE FUNCTION mal_divide(args integer[]) RETURNS integer AS $$
 131 BEGIN RETURN mal_intop('/', args); END; $$ LANGUAGE plpgsql;
 132
 133 INSERT INTO value (type_id, function_name) VALUES (11, 'mal_add');
 134 INSERT INTO value (type_id, function_name) VALUES (11, 'mal_subtract');
 135 INSERT INTO value (type_id, function_name) VALUES (11, 'mal_multiply');
 136 INSERT INTO value (type_id, function_name) VALUES (11, 'mal_divide');
 137
 138 -- repl_env is environment 0
 139 SELECT env_vset(0, '+', (SELECT value_id FROM value WHERE function_name = 'mal_add'));
 140 SELECT env_vset(0, '-', (SELECT value_id FROM value WHERE function_name = 'mal_subtract'));
 141 SELECT env_vset(0, '*', (SELECT value_id FROM value WHERE function_name = 'mal_multiply'));
 142 SELECT env_vset(0, '/', (SELECT value_id FROM value WHERE function_name = 'mal_divide'));
 143
 144
 145 CREATE OR REPLACE FUNCTION REP(line varchar) RETURNS varchar AS $$
 146 DECLARE
 147     output varchar;
 148 BEGIN
 149     -- RAISE NOTICE 'line is %', line;
 150     -- output := 'line: ' || line;
 151     RETURN PRINT(EVAL(READ(line), 0));
 152 END; $$ LANGUAGE plpgsql;