tokenize/1 done

common/utils.erl

@@ -10,16 +10,7 @@ try_parse_number(String) ->
 
 is_digit(Char) -> lists:member(Char, lists:seq($0, $9)).
 
-re_escape(Symbol) ->
-    case lists:member(Symbol, "[]\\^$.|?*+()") of
-        true ->
-            case is_integer(Symbol) of
-                true -> [$\ | [Symbol]];
-                false -> [$\ | Symbol]
-            end;
-        false ->
-            case is_integer(Symbol) of
-                true -> [Symbol];
-                false -> Symbol
-            end
-    end.
+re_escape(String) ->
+    io:fwrite("Token:~p, is binary: ~p~n", [String, is_binary(String)]),
+    Escaped = re:replace(String, "[\\[\\]\\\\^$.|?*+()]", "\\\\&", [global]),
+    Escaped.

reverse_polish_notation_evaluator/src/reverse_polish_notation_evaluator.erl

@@ -31,8 +31,18 @@ handle_token(Token, Stack, Position) ->
 
 
 tokenize(Expression) ->
-   Tokens = re:split(Expression, "(\\d+\\.?\\d*|[-+*/%//**])"),
-   lists:filter(fun(X) -> X =/= "" end, Tokens).
+   Tokens = re:split(Expression, "\\s+"),
+   FilteredTokens = lists:filter(fun(X) -> (X =/= "") and not(lists:member(X, "\s\t\n")) end, Tokens),
+   io:fwrite("~p~n", [FilteredTokens]),
+   Positions = lists:flatmap(fun(Token) ->
+      case re:run(Expression, utils:re_escape(Token), [global]) of
+         nomatch -> [];
+         {match, Captured} ->
+            io:fwrite("~p:~p~n", [utils:re_escape(Token), Captured]),
+            lists:map(fun({Index, _Length}) -> {Token, Index + 1} end, lists:flatten(Captured))
+      end
+   end, FilteredTokens),
+   Positions.
 
 
 
@@ -41,4 +51,4 @@ tokenize(Expression) ->
 
 
 start() ->
-   io:fwrite("~p~n", [tokenize(1 2 3 * + 4 -)]).
+   io:fwrite("~p~n", [tokenize("-11.4 2 3 / + * // ** % + 4 -")]).