A Erlang snippet to convert a currency strings or binary to a integer

currency.erl

-author("mlersch").
-module(currency).
-export([test/0, convert/1]).


convert(V) when is_binary(V)   -> convert(binary_to_list(V));
convert(V) when is_float(V)    -> round(V*100);
convert(V) when is_integer(V)  -> V*100;
convert(V) when is_list(V)     ->
  V1 = re:replace(re:replace(V, "[^0-9 ^, ^.]", "", [{return,list},unicode,global]), "\\h", "", [{return,list},global]),
  convert_strip_a(
    list_to_integer(re:replace(V1, "[\\. ,]", "", [{return,list},global])),
    string:rchr(V1, $,),
    string:rchr(V1, $.),
    length(string:substr(V1, string:rchr(V1, $,)+1)),
    length(string:substr(V1, string:rchr(V1, $.)+1))
  ).


%% when no "," or "."
convert_strip_a(V, KomPos, DotPos, _KomRest, _DotRest)
  when KomPos == 0
  andalso DotPos == 0
  -> V * 100;

%% last is "," and no "."
convert_strip_a(V, KomPos, DotPos, KomRest, _DotRest)
  when KomPos > DotPos
  -> convert_strip_b(V, KomRest);

%% last is "." and no ","
convert_strip_a(V, KomPos, DotPos, _KomRest, DotRest)
  when KomPos < DotPos
  -> convert_strip_b(V, DotRest).


%% 100, or 100,000
convert_strip_b(V, Rest) when Rest == 0 orelse Rest == 3 -> V * 100;
%% 100,0
convert_strip_b(V, Rest) when Rest == 1 -> V * 10;
%% 100,00
convert_strip_b(V, Rest) when Rest == 2 -> V.


test()->

  %% Testing floats and integers
  10000 = convert(100),
  10000 = convert(100.0),
  10000 = convert(100.00),

  %% Testing Regular strings
  10000 = convert("100"),
  10000 = convert("100,0"),
  10000 = convert("100,00"),
  10000 = convert("100.0"),
  10000 = convert("100.00"),

  100000 = convert("1000,00"),
  100000 = convert("1000.00"),
  100000 = convert("1.000,00"),
  100000 = convert("1,000.00"),
  100000 = convert("1,000"),
  100000 = convert("1.000"),

  100000000 = convert("1000000,00"),
  100000000 = convert("1000000.00"),
  100000000 = convert("1.000.000,00"),
  100000000 = convert("1,000,000.00"),
  100000000 = convert("1,000,000"),
  100000000 = convert("1.000.000"),

  %% Testing unicode chars
  10000 = convert("100 €"),
  10000 = convert("100,0 €"),
  10000 = convert("100,00 €"),
  10000 = convert("100.0 €"),
  10000 = convert("100.00 €"),

  100000 = convert("1000,00 €"),
  100000 = convert("1000.00 €"),
  100000 = convert("1.000,00 €"),
  100000 = convert("1,000.00 €"),
  100000 = convert("1,000 €"),
  100000 = convert("1.000 €"),

  100000000 = convert("1000000,00 €"),
  100000000 = convert("1000000.00 €"),
  100000000 = convert("1.000.000,00 €"),
  100000000 = convert("1,000,000.00 €"),
  100000000 = convert("1,000,000 €"),
  100000000 = convert("1.000.000 €"),


  %% Testing more text and prefixes
  10000 = convert("$100more text like $ۤ?#"),
  10000 = convert("$100,0more text like $ۤ?#"),
  10000 = convert("$100,00more text like $ۤ?#"),
  10000 = convert("$100.0more text like $ۤ?#"),
  10000 = convert("$100.00more text like $ۤ?#"),

  100000 = convert("$1000,00more text like $ۤ?#"),
  100000 = convert("$1000.00more text like $ۤ?#"),
  100000 = convert("$1.000,00more text like $ۤ?#"),
  100000 = convert("$1,000.00more text like $ۤ?#"),
  100000 = convert("$1,000more text like $ۤ?#"),
  100000 = convert("$1.000more text like $ۤ?#"),

  100000000 = convert("$1000000,00more text like $ۤ?#"),
  100000000 = convert("$1000000.00more text like $ۤ?#"),
  100000000 = convert("$1.000.000,00more text like $ۤ?#"),
  100000000 = convert("$1,000,000.00more text like $ۤ?#"),
  100000000 = convert("$1,000,000more text like $ۤ?#"),
  100000000 = convert("$1.000.000more text like $ۤ?#"),
  
  %% Testing irritating Chars and wrong separators
  100000 = convert("1,000,00"),
  100000 = convert("1.000.00"),
  100000 = convert("1,000,-"),
  100000 = convert("1.000,-"),
  100000 = convert("1,000,0-"),
  100000 = convert("1.000.0-"),
  100000 = convert("1,000,0-"),

  %% Test Ignore wrong thousand separators
  10000 = convert("1.00,00"),
  10000 = convert("1,00,00"),
  10000 = convert("1,00.00"),
  10000 = convert("1.00.00"),
  1000000 = convert("1.00.00,00"),
  1000000 = convert("1,00,00,00"),
  1000000 = convert("1,00,00.00"),
  1000000 = convert("1.00.00.00"),

  %% Test Ignore wrong thousand separators with 1 digit cent
  10000 = convert("1.00,0"),
  10000 = convert("1,00,0"),
  10000 = convert("1,00.0"),
  10000 = convert("1.00.0"),
  1000000 = convert("1.00.00,0"),
  1000000 = convert("1,00,00,0"),
  1000000 = convert("1,00,00.0"),
  1000000 = convert("1.00.00.0"),
  ok.