+my $float_e_format = qr/ ^ -? \d \. \d+ e [-+] \d+ $ /x;
+
+# Create another hash that maps floating point x.yyEzz representation to what
+# %stricter_to_file_of does for the equivalent rational. A typical entry in
+# the latter hash is
+#
+# 'nv=1/2' => 'Nv/1_2',
+#
+# From that, this loop creates an entry
+#
+# 'nv=5.00e-01' => 'Nv/1_2',
+#
+# %stricter_to_file_of contains far more than just the rationals. Instead we
+# use %utf8::nv_floating_to_rational which should have an entry for each
+# nv in the former hash.
+my %floating_to_file_of;
+foreach my $key (keys %utf8::nv_floating_to_rational) {
+ my $value = $utf8::nv_floating_to_rational{$key};
+ $floating_to_file_of{$key} = $utf8::stricter_to_file_of{"nv=$value"};
+}
+