plpgsql/step8_macros.sql

   1 -- ---------------------------------------------------------
   2 -- step8_macros.sql
   3
   4 \i init.sql
   5 \i io.sql
   6 \i types.sql
   7 \i reader.sql
   8 \i printer.sql
   9 \i envs.sql
  10 \i core.sql
  11
  12 -- ---------------------------------------------------------
  13
  14 CREATE SCHEMA mal;
  15
  16 -- read
  17 CREATE FUNCTION mal.READ(line varchar) RETURNS integer AS $$
  18 BEGIN
  19     RETURN reader.read_str(line);
  20 END; $$ LANGUAGE plpgsql;
  21
  22 -- eval
  23 CREATE FUNCTION mal.is_pair(ast integer) RETURNS boolean AS $$
  24 BEGIN
  25     RETURN types._sequential_Q(ast) AND types._count(ast) > 0;
  26 END; $$ LANGUAGE plpgsql;
  27
  28 CREATE FUNCTION mal.quasiquote(ast integer) RETURNS integer AS $$
  29 DECLARE
  30     a0   integer;
  31     a00  integer;
  32 BEGIN
  33     IF NOT mal.is_pair(ast) THEN
  34         RETURN types._list(ARRAY[types._symbolv('quote'), ast]);
  35     ELSE
  36         a0 := types._nth(ast, 0);
  37         IF types._symbol_Q(a0) AND a0 = types._symbolv('unquote') THEN
  38             RETURN types._nth(ast, 1);
  39         ELSE
  40             a00 := types._nth(a0, 0);
  41             IF types._symbol_Q(a00) AND
  42                a00 = types._symbolv('splice-unquote') THEN
  43                 RETURN types._list(ARRAY[types._symbolv('concat'),
  44                                          types._nth(a0, 1),
  45                                          mal.quasiquote(types._rest(ast))]);
  46             END IF;
  47         END IF;
  48         RETURN types._list(ARRAY[types._symbolv('cons'),
  49                                  mal.quasiquote(types._first(ast)),
  50                                  mal.quasiquote(types._rest(ast))]);
  51     END IF;
  52 END; $$ LANGUAGE plpgsql;
  53
  54 CREATE FUNCTION mal.is_macro_call(ast integer, env integer) RETURNS boolean AS $$
  55 DECLARE
  56     a0      integer;
  57     f       integer;
  58     result  boolean = false;
  59 BEGIN
  60     IF types._list_Q(ast) THEN
  61         a0 = types._first(ast);
  62         IF types._symbol_Q(a0) AND
  63            envs.find(env, types._valueToString(a0)) IS NOT NULL THEN
  64             f := envs.get(env, a0);
  65             SELECT macro INTO result FROM types.value WHERE value_id = f;
  66         END IF;
  67     END IF;
  68     RETURN result;
  69 END; $$ LANGUAGE plpgsql;
  70
  71 CREATE FUNCTION mal.macroexpand(ast integer, env integer) RETURNS integer AS $$
  72 DECLARE
  73     mac  integer;
  74 BEGIN
  75     WHILE mal.is_macro_call(ast, env)
  76     LOOP
  77         mac := envs.get(env, types._first(ast));
  78         ast := types._apply(mac, types._valueToArray(types._rest(ast)));
  79     END LOOP;
  80     RETURN ast;
  81 END; $$ LANGUAGE plpgsql;
  82
  83 CREATE FUNCTION mal.eval_ast(ast integer, env integer) RETURNS integer AS $$
  84 DECLARE
  85     type           integer;
  86     seq            integer[];
  87     eseq           integer[];
  88     hash           hstore;
  89     ehash          hstore;
  90     kv             RECORD;
  91     e              integer;
  92     result         integer;
  93 BEGIN
  94     SELECT type_id INTO type FROM types.value WHERE value_id = ast;
  95     CASE
  96     WHEN type = 7 THEN
  97     BEGIN
  98         result := envs.get(env, ast);
  99     END;
 100     WHEN type IN (8, 9) THEN
 101     BEGIN
 102         SELECT val_seq INTO seq FROM types.value WHERE value_id = ast;
 103         -- Evaluate each entry creating a new sequence
 104         FOR i IN 1 .. COALESCE(array_length(seq, 1), 0) LOOP
 105             eseq[i] := mal.EVAL(seq[i], env);
 106         END LOOP;
 107         INSERT INTO types.value (type_id, val_seq) VALUES (type, eseq)
 108             RETURNING value_id INTO result;
 109     END;
 110     WHEN type = 10 THEN
 111     BEGIN
 112         SELECT val_hash INTO hash FROM types.value WHERE value_id = ast;
 113         -- Evaluate each value for every key/value
 114         FOR kv IN SELECT * FROM each(hash) LOOP
 115             e := mal.EVAL(CAST(kv.value AS integer), env);
 116             IF ehash IS NULL THEN
 117                 ehash := hstore(kv.key, CAST(e AS varchar));
 118             ELSE
 119                 ehash := ehash || hstore(kv.key, CAST(e AS varchar));
 120             END IF;
 121         END LOOP;
 122         INSERT INTO types.value (type_id, val_hash) VALUES (type, ehash)
 123             RETURNING value_id INTO result;
 124     END;
 125     ELSE
 126         result := ast;
 127     END CASE;
 128
 129     RETURN result;
 130 END; $$ LANGUAGE plpgsql;
 131
 132 CREATE FUNCTION mal.EVAL(ast integer, env integer) RETURNS integer AS $$
 133 DECLARE
 134     type     integer;
 135     a0       integer;
 136     a0sym    varchar;
 137     a1       integer;
 138     let_env  integer;
 139     idx      integer;
 140     binds    integer[];
 141     el       integer;
 142     fn       integer;
 143     fname    varchar;
 144     args     integer[];
 145     cond     integer;
 146     fast     integer;
 147     fparams  integer;
 148     fenv     integer;
 149     result   integer;
 150 BEGIN
 151   LOOP
 152     -- PERFORM writeline(format('EVAL: %s [%s]', pr_str(ast), ast));
 153     SELECT type_id INTO type FROM types.value WHERE value_id = ast;
 154     IF type <> 8 THEN
 155         RETURN mal.eval_ast(ast, env);
 156     END IF;
 157
 158     ast := mal.macroexpand(ast, env);
 159     SELECT type_id INTO type FROM types.value WHERE value_id = ast;
 160     IF type <> 8 THEN
 161         RETURN mal.eval_ast(ast, env);
 162     END IF;
 163     IF types._count(ast) = 0 THEN
 164         RETURN ast;
 165     END IF;
 166
 167     a0 := types._first(ast);
 168     IF types._symbol_Q(a0) THEN
 169         a0sym := (SELECT val_string FROM types.value WHERE value_id = a0);
 170     ELSE
 171         a0sym := '__<*fn*>__';
 172     END IF;
 173
 174     CASE
 175     WHEN a0sym = 'def!' THEN
 176     BEGIN
 177         RETURN envs.set(env, types._nth(ast, 1),
 178                         mal.EVAL(types._nth(ast, 2), env));
 179     END;
 180     WHEN a0sym = 'let*' THEN
 181     BEGIN
 182         let_env := envs.new(env);
 183         a1 := types._nth(ast, 1);
 184         binds := (SELECT val_seq FROM types.value WHERE value_id = a1);
 185         idx := 1;
 186         WHILE idx < array_length(binds, 1) LOOP
 187             PERFORM envs.set(let_env, binds[idx],
 188                                       mal.EVAL(binds[idx+1], let_env));
 189             idx := idx + 2;
 190         END LOOP;
 191         env := let_env;
 192         ast := types._nth(ast, 2);
 193         CONTINUE; -- TCO
 194     END;
 195     WHEN a0sym = 'quote' THEN
 196     BEGIN
 197         RETURN types._nth(ast, 1);
 198     END;
 199     WHEN a0sym = 'quasiquote' THEN
 200     BEGIN
 201         ast := mal.quasiquote(types._nth(ast, 1));
 202         CONTINUE; -- TCO
 203     END;
 204     WHEN a0sym = 'defmacro!' THEN
 205     BEGIN
 206         fn := mal.EVAL(types._nth(ast, 2), env);
 207         fn := types._macro(fn);
 208         RETURN envs.set(env, types._nth(ast, 1), fn);
 209     END;
 210     WHEN a0sym = 'macroexpand' THEN
 211     BEGIN
 212         RETURN mal.macroexpand(types._nth(ast, 1), env);
 213     END;
 214     WHEN a0sym = 'do' THEN
 215     BEGIN
 216         PERFORM mal.eval_ast(types._slice(ast, 1, types._count(ast)-1), env);
 217         ast := types._nth(ast, types._count(ast)-1);
 218         CONTINUE; -- TCO
 219     END;
 220     WHEN a0sym = 'if' THEN
 221     BEGIN
 222         cond := mal.EVAL(types._nth(ast, 1), env);
 223         SELECT type_id INTO type FROM types.value WHERE value_id = cond;
 224         IF type = 0 OR type = 1 THEN -- nil or false
 225             IF types._count(ast) > 3 THEN
 226                 ast := types._nth(ast, 3);
 227                 CONTINUE; -- TCO
 228             ELSE
 229                 RETURN 0; -- nil
 230             END IF;
 231         ELSE
 232             ast := types._nth(ast, 2);
 233             CONTINUE; -- TCO
 234         END IF;
 235     END;
 236     WHEN a0sym = 'fn*' THEN
 237     BEGIN
 238         RETURN types._malfunc(types._nth(ast, 2), types._nth(ast, 1), env);
 239     END;
 240     ELSE
 241     BEGIN
 242         el := mal.eval_ast(ast, env);
 243         SELECT type_id, val_string, ast_id, params_id, env_id
 244             INTO type, fname, fast, fparams, fenv
 245             FROM types.value WHERE value_id = types._first(el);
 246         args := types._restArray(el);
 247         IF type = 11 THEN
 248             EXECUTE format('SELECT %s($1);', fname)
 249                 INTO result USING args;
 250             RETURN result;
 251         ELSIF type = 12 THEN
 252             env := envs.new(fenv, fparams, args);
 253             ast := fast;
 254             CONTINUE; -- TCO
 255         ELSE
 256             RAISE EXCEPTION 'Invalid function call';
 257         END IF;
 258     END;
 259     END CASE;
 260   END LOOP;
 261 END; $$ LANGUAGE plpgsql;
 262
 263 -- print
 264 CREATE FUNCTION mal.PRINT(exp integer) RETURNS varchar AS $$
 265 BEGIN
 266     RETURN printer.pr_str(exp);
 267 END; $$ LANGUAGE plpgsql;
 268
 269
 270 -- repl
 271
 272 -- repl_env is environment 0
 273
 274 CREATE FUNCTION mal.REP(line varchar) RETURNS varchar AS $$
 275 BEGIN
 276     RETURN mal.PRINT(mal.EVAL(mal.READ(line), 0));
 277 END; $$ LANGUAGE plpgsql;
 278
 279 -- core.sql: defined using SQL (in core.sql)
 280 -- repl_env is created and populated with core functions in by core.sql
 281 CREATE FUNCTION mal.mal_eval(args integer[]) RETURNS integer AS $$
 282 BEGIN
 283     RETURN mal.EVAL(args[1], 0);
 284 END; $$ LANGUAGE plpgsql;
 285 INSERT INTO types.value (type_id, val_string) VALUES (11, 'mal.mal_eval');
 286
 287 SELECT envs.vset(0, 'eval',
 288                    (SELECT value_id FROM types.value
 289                     WHERE val_string = 'mal.mal_eval')) \g '/dev/null'
 290 -- *ARGV* values are set by RUN
 291 SELECT envs.vset(0, '*ARGV*', mal.READ('()')) \g '/dev/null'
 292
 293
 294 -- core.mal: defined using the language itself
 295 SELECT mal.REP('(def! not (fn* (a) (if a false true)))') \g '/dev/null'
 296 SELECT mal.REP('(def! load-file (fn* (f) (eval (read-string (str "(do " (slurp f) "\nnil)")))))') \g '/dev/null'
 297 SELECT mal.REP('(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list ''if (first xs) (if (> (count xs) 1) (nth xs 1) (throw "odd number of forms to cond")) (cons ''cond (rest (rest xs)))))))') \g '/dev/null'
 298
 299 CREATE FUNCTION mal.MAIN(pwd varchar, argstring varchar DEFAULT NULL)
 300     RETURNS integer AS $$
 301 DECLARE
 302     line      varchar;
 303     output    varchar;
 304     allargs   integer;
 305 BEGIN
 306     PERFORM envs.vset(0, '*PWD*', types._stringv(pwd));
 307
 308     IF argstring IS NOT NULL THEN
 309         allargs := mal.READ(argstring);
 310         PERFORM envs.vset(0, '*ARGV*', types._rest(allargs));
 311         PERFORM mal.REP('(load-file ' ||
 312                         printer.pr_str(types._first(allargs)) || ')');
 313         PERFORM io.close(1);
 314         PERFORM io.wait_flushed(1);
 315         RETURN 0;
 316     END IF;
 317
 318     WHILE true
 319     LOOP
 320         BEGIN
 321             line := io.readline('user> ', 0);
 322             IF line IS NULL THEN
 323                 PERFORM io.close(1);
 324                 RETURN 0;
 325             END IF;
 326             IF line NOT IN ('', E'\n') THEN
 327                 output := mal.REP(line);
 328                 PERFORM io.writeline(output);
 329             END IF;
 330
 331             EXCEPTION WHEN OTHERS THEN
 332                 PERFORM io.writeline('Error: ' || SQLERRM);
 333         END;
 334     END LOOP;
 335 END; $$ LANGUAGE plpgsql;