plsql/step0_repl.sql

   1 --\i init.sql
   2 @io.sql
   3
   4 CREATE OR REPLACE PACKAGE mal IS
   5
   6 FUNCTION MAIN(args varchar DEFAULT '()') RETURN integer;
   7
   8 END mal;
   9 /
  10
  11 CREATE OR REPLACE PACKAGE BODY mal IS
  12
  13 FUNCTION MAIN(args varchar DEFAULT '()') RETURN integer IS
  14     line      CLOB;
  15
  16     -- read
  17     FUNCTION READ(line varchar) RETURN varchar IS
  18     BEGIN
  19         RETURN line;
  20     END;
  21
  22     -- eval
  23     FUNCTION EVAL(ast varchar, env varchar) RETURN varchar IS
  24     BEGIN
  25         RETURN ast;
  26     END;
  27
  28     -- print
  29     FUNCTION PRINT(exp varchar) RETURN varchar IS
  30     BEGIN
  31         RETURN exp;
  32     END;
  33
  34     -- repl
  35     FUNCTION REP(line varchar) RETURN varchar IS
  36     BEGIN
  37         RETURN PRINT(EVAL(READ(line), ''));
  38     END;
  39
  40 BEGIN
  41     WHILE true LOOP
  42         BEGIN
  43             line := io.readline('user> ', 0);
  44             IF line = EMPTY_CLOB() THEN CONTINUE; END IF;
  45             IF line IS NOT NULL THEN
  46                 io.writeline(REP(line));
  47             END IF;
  48
  49             EXCEPTION WHEN OTHERS THEN
  50                 IF SQLCODE = -20001 THEN  -- io read stream closed
  51                     io.close(1);  -- close output stream
  52                     RETURN 0;
  53                 END IF;
  54                 io.writeline('Error: ' || SQLERRM);
  55                 io.writeline(dbms_utility.format_error_backtrace);
  56         END;
  57     END LOOP;
  58 END;
  59
  60 END mal;
  61 /
  62 show errors;
  63
  64 quit;