[Octave-bug-tracker] [bug #34713] str2double() ignores spaces and multiple commas

[Kris Thielemans]

Follow-up Comment #4, bug #34713 (project octave):

It turns out that we could let istream>> do the comma handling by setting the
local appropriatelly by simply removing the lines that remove the comma and
setting the local there the something like en_US (see code below).

With this, all current tests succeed and we also have good handling of
comma's:

octave> str2double('2,235.6 + 35,564.3i')
ans =  2.2356e+03 + 3.5564e+04i
octave> str2double('2,23,5.6')
ans = NaN

This solution is very elegant, but unfortunately has a major problem: local
naming is not set by the standard (on Ubuntu 11.10 I can use "en_US.UTF-8",
but Microsoft seems to use "english_US" (see
http://msdn.microsoft.com/en-us/library/hzz3tw78.aspx), and it's not clear if
en_US is installed on all systems in any case. I have no solution for this.

Of course, arguably str2double should use the system local anyway, but that
would seem to break matlab compatibility.

$ hg diff str2double.cc 
diff -r e5e74694c690 src/DLD-FUNCTIONS/str2double.cc
--- a/src/DLD-FUNCTIONS/str2double.cc   Wed Dec 21 09:08:10 2011 +0000
+++ b/src/DLD-FUNCTIONS/str2double.cc   Wed Dec 21 11:34:41 2011 +0000
@@ -227,13 +227,10 @@
 {
   Complex val (0.0, 0.0);
 
-  std::string str = str_arg;
+  std::istringstream is (str_arg);
+  // handle comma's
+  is.imbue( std::locale("en_US.UTF-8") );
 
-  // FIXME -- removing all commas does too much...
-  std::string::iterator se = str.end ();
-  se = std::remove (str.begin (), se, ',');
-  str.erase (se, str.end ());
-  std::istringstream is (str);
 


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