matlab/reader.m

   1 % this is just being used as a namespace
   2 classdef reader
   3     methods (Static = true)
   4         function tokens = tokenize(str)
   5             re = '[\s,]*(~@|[\[\]{}()''`~^@]|"(?:\\.|[^\\"])*"|;.*|[^\s\[\]{}(''"`,;)]*)';
   6             % extract the capture group (to ignore spaces and commas)
   7             tokens = cellfun(@(x) x(1), regexp(str, re, 'tokens'));
   8         end
   9
  10         function atm = read_atom(rdr)
  11             token = rdr.next();
  12             %fprintf('in read_atom: %s\n', token);
  13             if not(isempty(regexp(token, '^-?[0-9]+$', 'match')))
  14                 atm = str2double(token);
  15             elseif strcmp(token(1), '"')
  16                 atm = token(2:length(token)-1);
  17             elseif strcmp(token, 'nil')
  18                 atm = types.nil;
  19             elseif strcmp(token, 'true')
  20                 atm = true;
  21             elseif strcmp(token, 'false')
  22                 atm = false;
  23             else
  24                 atm = types.Symbol(token);
  25             end
  26         end
  27
  28         function lst = read_list(rdr)
  29             %fprintf('in read_list\n');
  30             lst = {};
  31             token = rdr.next();
  32             if not(strcmp(token, '('))
  33                 error('expected ''(''');
  34             end
  35             token = rdr.peek();
  36             while true
  37                 if eq(token, false)
  38                     error('expected '')''');
  39                 end
  40                 if strcmp(token, ')'), break, end
  41                 lst{length(lst)+1} = reader.read_form(rdr);
  42                 token = rdr.peek();
  43             end
  44             rdr.next();
  45         end
  46
  47         function ast = read_form(rdr)
  48             %fprintf('in read_form\n');
  49             token = rdr.peek();
  50             switch token(1)
  51             case ')'
  52                 error('unexpected '')''');
  53             case '('
  54                 ast = reader.read_list(rdr);
  55             otherwise
  56                 ast = reader.read_atom(rdr);
  57             end
  58         end
  59
  60         function ast = read_str(str)
  61             %fprintf('in read_str\n');
  62             tokens = reader.tokenize(str);
  63             rdr = Reader(tokens);
  64             ast = reader.read_form(rdr);
  65         end
  66     end
  67 end