matlab/step2_eval.m

   1 function step2_eval(varargin), main(varargin), end
   2
   3 % read
   4 function ret = READ(str)
   5     ret = reader.read_str(str);
   6 end
   7
   8 % eval
   9 function ret = eval_ast(ast, env)
  10     switch class(ast)
  11     case 'types.Symbol'
  12         ret = env(ast.name);
  13     case 'types.List'
  14         ret = types.List();
  15         for i=1:length(ast)
  16             ret.append(EVAL(ast.get(i), env));
  17         end
  18     case 'types.Vector'
  19         ret = types.Vector();
  20         for i=1:length(ast)
  21             ret.append(EVAL(ast.get(i), env));
  22         end
  23     case 'types.HashMap'
  24         ret = types.HashMap();
  25         ks = ast.keys();
  26         for i=1:length(ks)
  27             k = ks{i};
  28             ret.set(EVAL(k, env), EVAL(ast.get(k), env));
  29         end
  30     otherwise
  31         ret = ast;
  32     end
  33 end
  34
  35 function ret = EVAL(ast, env)
  36     %fprintf('EVAL: %s\n', printer.pr_str(ast, true));
  37     if ~type_utils.list_Q(ast)
  38         ret = eval_ast(ast, env);
  39         return;
  40     end
  41
  42     % apply
  43     if length(ast) == 0
  44         ret = ast;
  45         return;
  46     end
  47     el = eval_ast(ast, env);
  48     f = el.get(1);
  49     args = el.data(2:end);
  50     ret = f(args{:});
  51 end
  52
  53 % print
  54 function ret = PRINT(ast)
  55     ret = printer.pr_str(ast, true);
  56 end
  57
  58 % REPL
  59 function ret = rep(str, env)
  60     ret = PRINT(EVAL(READ(str), env));
  61 end
  62
  63 function main(args)
  64     if exist('OCTAVE_VERSION', 'builtin') ~= 0
  65         repl_env = Dict();
  66     else
  67         repl_env = containers.Map();
  68     end
  69     repl_env('+') = @(a,b) a+b;
  70     repl_env('-') = @(a,b) a-b;
  71     repl_env('*') = @(a,b) a*b;
  72     repl_env('/') = @(a,b) floor(a/b);
  73
  74     %cleanObj = onCleanup(@() disp('*** here1 ***'));
  75     while (true)
  76         try
  77             line = input('user> ', 's');
  78         catch err
  79             return
  80         end
  81         if strcmp(strtrim(line),''), continue, end
  82         try
  83             fprintf('%s\n', rep(line, repl_env));
  84         catch err
  85             fprintf('Error: %s\n', err.message);
  86             type_utils.print_stack(err);
  87         end
  88     end
  89 end