vhdl/step8_macros.vhdl

   1 entity step8_macros is
   2 end entity step8_macros;
   3
   4 library STD;
   5 use STD.textio.all;
   6 library WORK;
   7 use WORK.pkg_readline.all;
   8 use WORK.types.all;
   9 use WORK.printer.all;
  10 use WORK.reader.all;
  11 use WORK.env.all;
  12 use WORK.core.all;
  13
  14 architecture test of step8_macros is
  15
  16   shared variable repl_env: env_ptr;
  17
  18   procedure mal_READ(str: in string; ast: out mal_val_ptr; err: out mal_val_ptr) is
  19   begin
  20     read_str(str, ast, err);
  21   end procedure mal_READ;
  22
  23   procedure is_pair(ast: inout mal_val_ptr; pair: out boolean) is
  24   begin
  25     pair := is_sequential_type(ast.val_type) and ast.seq_val'length > 0;
  26   end procedure is_pair;
  27
  28   procedure quasiquote(ast: inout mal_val_ptr; result: out mal_val_ptr) is
  29     variable ast_pair, a0_pair: boolean;
  30     variable seq: mal_seq_ptr;
  31     variable a0, rest: mal_val_ptr;
  32   begin
  33     is_pair(ast, ast_pair);
  34     if not ast_pair then
  35       seq := new mal_seq(0 to 1);
  36       new_symbol("quote", seq(0));
  37       seq(1) := ast;
  38       new_seq_obj(mal_list, seq, result);
  39       return;
  40     end if;
  41     a0 := ast.seq_val(0);
  42     if a0.val_type = mal_symbol and a0.string_val.all = "unquote" then
  43       result := ast.seq_val(1);
  44     else
  45       is_pair(a0, a0_pair);
  46       if a0_pair and a0.seq_val(0).val_type = mal_symbol and a0.seq_val(0).string_val.all = "splice-unquote" then
  47         seq := new mal_seq(0 to 2);
  48         new_symbol("concat", seq(0));
  49         seq(1) := a0.seq_val(1);
  50         seq_drop_prefix(ast, 1, rest);
  51         quasiquote(rest, seq(2));
  52         new_seq_obj(mal_list, seq, result);
  53       else
  54         seq := new mal_seq(0 to 2);
  55         new_symbol("cons", seq(0));
  56         quasiquote(a0, seq(1));
  57         seq_drop_prefix(ast, 1, rest);
  58         quasiquote(rest, seq(2));
  59         new_seq_obj(mal_list, seq, result);
  60       end if;
  61     end if;
  62   end procedure quasiquote;
  63
  64   -- Forward declaration
  65   procedure EVAL(in_ast: inout mal_val_ptr; in_env: inout env_ptr; result: out mal_val_ptr; err: out mal_val_ptr);
  66
  67   procedure apply_func(fn: inout mal_val_ptr; args: inout mal_val_ptr; result: out mal_val_ptr; err: out mal_val_ptr);
  68
  69   procedure is_macro_call(ast: inout mal_val_ptr; env: inout env_ptr; is_macro: out boolean) is
  70     variable f, env_err: mal_val_ptr;
  71   begin
  72     is_macro := false;
  73     if ast.val_type = mal_list and
  74        ast.seq_val'length > 0 and
  75        ast.seq_val(0).val_type = mal_symbol then
  76       env_get(env, ast.seq_val(0), f, env_err);
  77       if env_err = null and f /= null and
  78          f.val_type = mal_fn and f.func_val.f_is_macro then
  79         is_macro := true;
  80       end if;
  81     end if;
  82   end procedure is_macro_call;
  83
  84   procedure macroexpand(in_ast: inout mal_val_ptr; env: inout env_ptr; result: out mal_val_ptr; err: out mal_val_ptr) is
  85     variable ast, macro_fn, call_args, macro_err: mal_val_ptr;
  86     variable is_macro: boolean;
  87   begin
  88     ast := in_ast;
  89     is_macro_call(ast, env, is_macro);
  90     while is_macro loop
  91       env_get(env, ast.seq_val(0), macro_fn, macro_err);
  92       seq_drop_prefix(ast, 1, call_args);
  93       apply_func(macro_fn, call_args, ast, macro_err);
  94       if macro_err /= null then
  95         err := macro_err;
  96         return;
  97       end if;
  98       is_macro_call(ast, env, is_macro);
  99     end loop;
 100     result := ast;
 101   end procedure macroexpand;
 102
 103   procedure fn_eval(args: inout mal_val_ptr; result: out mal_val_ptr; err: out mal_val_ptr) is
 104   begin
 105     EVAL(args.seq_val(0), repl_env, result, err);
 106   end procedure fn_eval;
 107
 108   procedure fn_swap(args: inout mal_val_ptr; result: out mal_val_ptr; err: out mal_val_ptr) is
 109     variable atom: mal_val_ptr := args.seq_val(0);
 110     variable fn: mal_val_ptr := args.seq_val(1);
 111     variable call_args_seq: mal_seq_ptr;
 112     variable call_args, eval_res, sub_err: mal_val_ptr;
 113   begin
 114     call_args_seq := new mal_seq(0 to args.seq_val'length - 2);
 115     call_args_seq(0) := atom.seq_val(0);
 116     call_args_seq(1 to call_args_seq'length - 1) := args.seq_val(2 to args.seq_val'length - 1);
 117     new_seq_obj(mal_list, call_args_seq, call_args);
 118     apply_func(fn, call_args, eval_res, sub_err);
 119     if sub_err /= null then
 120       err := sub_err;
 121       return;
 122     end if;
 123     atom.seq_val(0) := eval_res;
 124     result := eval_res;
 125   end procedure fn_swap;
 126
 127   procedure apply_native_func(func_sym: inout mal_val_ptr; args: inout mal_val_ptr; result: out mal_val_ptr; err: out mal_val_ptr) is
 128   begin
 129     if func_sym.string_val.all = "eval" then
 130       fn_eval(args, result, err);
 131     elsif func_sym.string_val.all = "swap!" then
 132       fn_swap(args, result, err);
 133     else
 134       eval_native_func(func_sym, args, result, err);
 135     end if;
 136   end procedure apply_native_func;
 137
 138   procedure apply_func(fn: inout mal_val_ptr; args: inout mal_val_ptr; result: out mal_val_ptr; err: out mal_val_ptr) is
 139     variable fn_env: env_ptr;
 140   begin
 141     case fn.val_type is
 142       when mal_nativefn =>
 143         apply_native_func(fn, args, result, err);
 144       when mal_fn =>
 145         new_env(fn_env, fn.func_val.f_env, fn.func_val.f_args, args);
 146         EVAL(fn.func_val.f_body, fn_env, result, err);
 147       when others =>
 148         new_string("not a function", err);
 149         return;
 150     end case;
 151   end procedure apply_func;
 152
 153   procedure eval_ast_seq(ast_seq: inout mal_seq_ptr; env: inout env_ptr; result: inout mal_seq_ptr; err: out mal_val_ptr) is
 154     variable eval_err: mal_val_ptr;
 155   begin
 156     result := new mal_seq(0 to ast_seq'length - 1);
 157     for i in result'range loop
 158       EVAL(ast_seq(i), env, result(i), eval_err);
 159       if eval_err /= null then
 160         err := eval_err;
 161         return;
 162       end if;
 163     end loop;
 164   end procedure eval_ast_seq;
 165
 166   procedure eval_ast(ast: inout mal_val_ptr; env: inout env_ptr; result: out mal_val_ptr; err: out mal_val_ptr) is
 167     variable key, val, eval_err, env_err: mal_val_ptr;
 168     variable new_seq: mal_seq_ptr;
 169     variable i: integer;
 170   begin
 171     case ast.val_type is
 172       when mal_symbol =>
 173         env_get(env, ast, val, env_err);
 174         if env_err /= null then
 175           err := env_err;
 176           return;
 177         end if;
 178         result := val;
 179         return;
 180       when mal_list | mal_vector | mal_hashmap =>
 181         eval_ast_seq(ast.seq_val, env, new_seq, eval_err);
 182         if eval_err /= null then
 183           err := eval_err;
 184           return;
 185         end if;
 186         new_seq_obj(ast.val_type, new_seq, result);
 187         return;
 188       when others =>
 189         result := ast;
 190         return;
 191     end case;
 192   end procedure eval_ast;
 193
 194   procedure EVAL(in_ast: inout mal_val_ptr; in_env: inout env_ptr; result: out mal_val_ptr; err: out mal_val_ptr) is
 195     variable i: integer;
 196     variable ast, evaled_ast, a0, call_args, val, vars, sub_err, fn: mal_val_ptr;
 197     variable env, let_env, fn_env: env_ptr;
 198   begin
 199     ast := in_ast;
 200     env := in_env;
 201     loop
 202       if ast.val_type /= mal_list then
 203         eval_ast(ast, env, result, err);
 204         return;
 205       end if;
 206
 207       macroexpand(ast, env, ast, sub_err);
 208       if sub_err /= null then
 209         err := sub_err;
 210         return;
 211       end if;
 212       if ast.val_type /= mal_list then
 213         eval_ast(ast, env, result, err);
 214         return;
 215       end if;
 216       if ast.seq_val'length = 0 then
 217         result := ast;
 218         return;
 219       end if;
 220
 221       a0 := ast.seq_val(0);
 222       if a0.val_type = mal_symbol then
 223         if a0.string_val.all = "def!" then
 224           EVAL(ast.seq_val(2), env, val, sub_err);
 225           if sub_err /= null then
 226             err := sub_err;
 227             return;
 228           end if;
 229           env_set(env, ast.seq_val(1), val);
 230           result := val;
 231           return;
 232
 233         elsif a0.string_val.all = "let*" then
 234           vars := ast.seq_val(1);
 235           new_env(let_env, env);
 236           i := 0;
 237           while i < vars.seq_val'length loop
 238             EVAL(vars.seq_val(i + 1), let_env, val, sub_err);
 239             if sub_err /= null then
 240               err := sub_err;
 241               return;
 242             end if;
 243             env_set(let_env, vars.seq_val(i), val);
 244             i := i + 2;
 245           end loop;
 246           env := let_env;
 247           ast := ast.seq_val(2);
 248           next; -- TCO
 249
 250         elsif a0.string_val.all = "quote" then
 251           result := ast.seq_val(1);
 252           return;
 253
 254         elsif a0.string_val.all = "quasiquote" then
 255           quasiquote(ast.seq_val(1), ast);
 256           next; -- TCO
 257
 258         elsif a0.string_val.all = "defmacro!" then
 259           EVAL(ast.seq_val(2), env, val, sub_err);
 260           if sub_err /= null then
 261             err := sub_err;
 262             return;
 263           end if;
 264           val.func_val.f_is_macro := true;
 265           env_set(env, ast.seq_val(1), val);
 266           result := val;
 267           return;
 268
 269         elsif a0.string_val.all = "macroexpand" then
 270           macroexpand(ast.seq_val(1), env, result, err);
 271           return;
 272
 273         elsif a0.string_val.all = "do" then
 274           for i in 1 to ast.seq_val'high - 1 loop
 275             EVAL(ast.seq_val(i), env, result, sub_err);
 276             if sub_err /= null then
 277               err := sub_err;
 278               return;
 279             end if;
 280           end loop;
 281           ast := ast.seq_val(ast.seq_val'high);
 282           next; -- TCO
 283
 284         elsif a0.string_val.all = "if" then
 285           EVAL(ast.seq_val(1), env, val, sub_err);
 286           if sub_err /= null then
 287             err := sub_err;
 288             return;
 289           end if;
 290           if val.val_type = mal_nil or val.val_type = mal_false then
 291             if ast.seq_val'length > 3 then
 292               ast := ast.seq_val(3);
 293             else
 294               new_nil(result);
 295               return;
 296             end if;
 297           else
 298             ast := ast.seq_val(2);
 299           end if;
 300           next; -- TCO
 301
 302         elsif a0.string_val.all = "fn*" then
 303           new_fn(ast.seq_val(2), ast.seq_val(1), env, result);
 304           return;
 305
 306         end if;
 307       end if;
 308
 309       eval_ast(ast, env, evaled_ast, sub_err);
 310       if sub_err /= null then
 311         err := sub_err;
 312         return;
 313       end if;
 314       seq_drop_prefix(evaled_ast, 1, call_args);
 315       fn := evaled_ast.seq_val(0);
 316       case fn.val_type is
 317         when mal_nativefn =>
 318           apply_native_func(fn, call_args, result, err);
 319           return;
 320         when mal_fn =>
 321           new_env(fn_env, fn.func_val.f_env, fn.func_val.f_args, call_args);
 322           env := fn_env;
 323           ast := fn.func_val.f_body;
 324           next; -- TCO
 325         when others =>
 326           new_string("not a function", err);
 327           return;
 328       end case;
 329     end loop;
 330   end procedure EVAL;
 331
 332   procedure mal_PRINT(exp: inout mal_val_ptr; result: out line) is
 333   begin
 334     pr_str(exp, true, result);
 335   end procedure mal_PRINT;
 336
 337   procedure RE(str: in string; env: inout env_ptr; result: out mal_val_ptr; err: out mal_val_ptr) is
 338     variable ast, read_err: mal_val_ptr;
 339   begin
 340     mal_READ(str, ast, read_err);
 341     if read_err /= null then
 342       err := read_err;
 343       result := null;
 344       return;
 345     end if;
 346     if ast = null then
 347       result := null;
 348       return;
 349     end if;
 350     EVAL(ast, env, result, err);
 351   end procedure RE;
 352
 353   procedure REP(str: in string; env: inout env_ptr; result: out line; err: out mal_val_ptr) is
 354     variable eval_res, eval_err: mal_val_ptr;
 355   begin
 356     RE(str, env, eval_res, eval_err);
 357     if eval_err /= null then
 358       err := eval_err;
 359       result := null;
 360       return;
 361     end if;
 362     mal_PRINT(eval_res, result);
 363   end procedure REP;
 364
 365   procedure set_argv(e: inout env_ptr; program_file: inout line) is
 366     variable argv_var_name: string(1 to 6) := "*ARGV*";
 367     variable argv_sym, argv_list: mal_val_ptr;
 368     file f: text;
 369     variable status: file_open_status;
 370     variable one_line: line;
 371     variable seq: mal_seq_ptr;
 372     variable element: mal_val_ptr;
 373   begin
 374     program_file := null;
 375     seq := new mal_seq(0 to -1);
 376     file_open(status, f, external_name => "vhdl_argv.tmp", open_kind => read_mode);
 377     if status = open_ok then
 378       if not endfile(f) then
 379         readline(f, program_file);
 380         while not endfile(f) loop
 381           readline(f, one_line);
 382           new_string(one_line.all, element);
 383           seq := new mal_seq'(seq.all & element);
 384         end loop;
 385       end if;
 386       file_close(f);
 387     end if;
 388     new_seq_obj(mal_list, seq, argv_list);
 389     new_symbol(argv_var_name, argv_sym);
 390     env_set(e, argv_sym, argv_list);
 391   end procedure set_argv;
 392
 393   procedure repl is
 394     variable is_eof: boolean;
 395     variable program_file, input_line, result: line;
 396     variable eval_sym, eval_fn, dummy_val, err: mal_val_ptr;
 397     variable outer: env_ptr;
 398     variable eval_func_name: string(1 to 4) := "eval";
 399   begin
 400     outer := null;
 401     new_env(repl_env, outer);
 402
 403     -- core.EXT: defined using VHDL (see core.vhdl)
 404     define_core_functions(repl_env);
 405     new_symbol(eval_func_name, eval_sym);
 406     new_nativefn(eval_func_name, eval_fn);
 407     env_set(repl_env, eval_sym, eval_fn);
 408     set_argv(repl_env, program_file);
 409
 410     -- core.mal: defined using the language itself
 411     RE("(def! not (fn* (a) (if a false true)))", repl_env, dummy_val, err);
 412     RE("(def! load-file (fn* (f) (eval (read-string (str " & '"' & "(do " & '"' & " (slurp f) " & '"' & "\nnil)" & '"' & ")))))", repl_env, dummy_val, err);
 413     RE("(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)))))))", repl_env, dummy_val, err);
 414
 415     if program_file /= null then
 416       REP("(load-file " & '"' & program_file.all & '"' & ")", repl_env, result, err);
 417       return;
 418     end if;
 419
 420     loop
 421       mal_readline("user> ", is_eof, input_line);
 422       exit when is_eof;
 423       next when input_line'length = 0;
 424       REP(input_line.all, repl_env, result, err);
 425       if err /= null then
 426         pr_str(err, false, result);
 427         result := new string'("Error: " & result.all);
 428       end if;
 429       if result /= null then
 430         mal_printline(result.all);
 431       end if;
 432       deallocate(result);
 433       deallocate(err);
 434     end loop;
 435     mal_printline("");
 436   end procedure repl;
 437
 438 begin
 439   repl;
 440 end architecture test;