Description:
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The function is_numeric() fails when the input is a value with thousand and decimal separators.

For example: 4.000,56 or 4,000.56.

We had a short discussion about this in #php irc channel and found out the following:

"4,000.56" = is USA notation
"4.000,56" = is European notation

They are perfectly valid numeric values, used in currency/weight/cubic centimeters/etc.


Suggested solutions:

1) Both notations should be accepted.

2) Only one notation should be accepted and PHP will decide which one, based on the Locale of the server/setup.

Any other suggestion is welcome.


Reproduce code:
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Reproduction code:

<?php

$dolars = "4,000.56";
$euros = "4.000,56";

$rc = is_numeric($dolars);
var_dump($rc);

$rc = is_numeric($euros);
var_dump($rc);

?>

Expected result:
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is_numeric should have returned TRUE in both cases.


Actual result:
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is_numeric returns false for both.