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,]*(~@|[\[\]{}()''`~^@]|"(?:\\.|[^\\"])*"|;[^\n]*|[^\s\[\]{}(''"`,;)]*)';
   6             % extract the capture group (to ignore spaces and commas)
   7             tokens = cellfun(@(x) x(1), regexp(str, re, 'tokens'));
   8             comments = cellfun(@(x) length(x) > 0 && x(1) == ';', tokens);
   9             tokens = tokens(~comments);
  10         end
  11
  12         function atm = read_atom(rdr)
  13             token = rdr.next();
  14             %fprintf('in read_atom: %s\n', token);
  15             if not(isempty(regexp(token, '^-?[0-9]+$', 'match')))
  16                 atm = str2double(token);
  17             elseif strcmp(token(1), '"')
  18                 atm = token(2:length(token)-1);
  19                 atm = strrep(atm, '\\', char(255));
  20                 atm = strrep(atm, '\"', '"');
  21                 atm = strrep(atm, '\n', char(10));
  22                 atm = strrep(atm, char(255), '\');
  23             elseif strcmp(token(1), ':')
  24                 s = token(2:end);
  25                 atm = type_utils.keyword(s);
  26             elseif strcmp(token, 'nil')
  27                 atm = type_utils.nil;
  28             elseif strcmp(token, 'true')
  29                 atm = true;
  30             elseif strcmp(token, 'false')
  31                 atm = false;
  32             else
  33                 atm = types.Symbol(token);
  34             end
  35         end
  36
  37         function seq = read_seq(rdr, start, last)
  38             %fprintf('in read_seq\n');
  39             seq = {};
  40             token = rdr.next();
  41             if not(strcmp(token, start))
  42                 error(sprintf('expected ''%s''', start));
  43             end
  44             token = rdr.peek();
  45             while true
  46                 if eq(token, false)
  47                     error(sprintf('expected ''%s''', last));
  48                 end
  49                 if strcmp(token, last), break, end
  50                 seq{end+1} = reader.read_form(rdr);
  51                 token = rdr.peek();
  52             end
  53             rdr.next();
  54         end
  55
  56         function lst = read_list(rdr)
  57             seq = reader.read_seq(rdr, '(', ')');
  58             lst = types.List(seq{:});
  59         end
  60
  61         function vec = read_vector(rdr)
  62             seq = reader.read_seq(rdr, '[', ']');
  63             vec = types.Vector(seq{:});
  64         end
  65
  66         function map = read_hash_map(rdr)
  67             seq = reader.read_seq(rdr, '{', '}');
  68             map = types.HashMap(seq{:});
  69         end
  70
  71         function ast = read_form(rdr)
  72             %fprintf('in read_form\n');
  73             token = rdr.peek();
  74             switch token
  75             case ''''
  76                 rdr.next();
  77                 ast = types.List(types.Symbol('quote'), ...
  78                                  reader.read_form(rdr));
  79             case '`'
  80                 rdr.next();
  81                 ast = types.List(types.Symbol('quasiquote'), ...
  82                                  reader.read_form(rdr));
  83             case '~'
  84                 rdr.next();
  85                 ast = types.List(types.Symbol('unquote'), ...
  86                                  reader.read_form(rdr));
  87             case '~@'
  88                 rdr.next();
  89                 ast = types.List(types.Symbol('splice-unquote'), ...
  90                                  reader.read_form(rdr));
  91             case '^'
  92                 rdr.next();
  93                 meta = reader.read_form(rdr);
  94                 ast = types.List(types.Symbol('with-meta'), ...
  95                                  reader.read_form(rdr), meta);
  96             case '@'
  97                 rdr.next();
  98                 ast = types.List(types.Symbol('deref'), ...
  99                                  reader.read_form(rdr));
 100
 101             case ')'
 102                 error('unexpected '')''');
 103             case '('
 104                 ast = reader.read_list(rdr);
 105             case ']'
 106                 error('unexpected '']''');
 107             case '['
 108                 ast = reader.read_vector(rdr);
 109             case '}'
 110                 error('unexpected ''}''');
 111             case '{'
 112                 ast = reader.read_hash_map(rdr);
 113             otherwise
 114                 ast = reader.read_atom(rdr);
 115             end
 116         end
 117
 118         function ast = read_str(str)
 119             %fprintf('in read_str\n');
 120             tokens = reader.tokenize(str);
 121             %disp(tokens);
 122             rdr = types.Reader(tokens);
 123             ast = reader.read_form(rdr);
 124         end
 125     end
 126 end