my @names = qw(
  amp lt gt apos quot nbsp iexcl cent pound curren yen brvbar sect uml
  copy ordf laquo not shy reg macr deg plusmn sup2 sup3 acute micro
  para middot cedil sup1 ordm raquo frac14 frac12 frac34 iquest Agrave
  Aacute Acirc Atilde Auml Aring AElig Ccedil Egrave Eacute Ecirc Euml
  Igrave Iacute Icirc Iuml ETH Ntilde Ograve Oacute Ocirc Otilde Ouml
  times Oslash Ugrave Uacute Ucirc Uuml Yacute THORN szlig agrave
  aacute acirc atilde auml aring aelig ccedil egrave eacute ecirc euml
  igrave iacute icirc iuml eth ntilde ograve oacute ocirc otilde ouml
  divide oslash ugrave uacute ucirc uuml yacute thorn yuml OElig oelig
  Scaron scaron Yuml fnof circ tilde ensp emsp thinsp zwnj zwj lrm rlm
  ndash mdash lsquo rsquo sbquo ldquo rdquo bdquo dagger Dagger permil
  lsaquo rsaquo euro Alpha Beta Gamma Delta Epsilon Zeta Eta Theta
  Iota Kappa Lambda Mu Nu Xi Omicron Pi Rho Sigma Tau Upsilon Phi Chi
  Psi Omega alpha beta gamma delta epsilon zeta eta theta iota kappa
  lambda mu nu xi omicron pi rho sigmaf sigma tau upsilon phi chi psi
  omega thetasym upsih piv bull hellip prime prime oline frasl weierp
  image real trade alefsym larr uarr rarr darr harr crarr larr uarr
  rarr darr harr forall part exist empty nabla isin notin ni prod sum
  minus lowast radic prop infin ang and or cap cup int there4 sim cong
  asymp ne equiv le ge sub sup nsub sube supe oplus otimes perp sdot
  lceil rceil lfloor rfloor lang rang loz
  spades clubs hearts diams
);

##</code><code>##

my %isname;
$isname{$_} = 1 foreach @names;
if($isname{$name}) ...

##</code><code>##

if($name ~~ @names) ...

##</code><code>##

if(grep $name eq $_, @names) ...

##</code><code>##

use Regex::PreSuf;
my $re = presuf(@names);
if($name =~ /^($re)$/o) ...

##</code><code>##

my $re = join '|', @names;
if($name =~ /^($re)$/o) ...

##</code><code>##

my $names = ' ' . join(' ', @names) . ' ';
if(index($names, " $name ") >= 0) ...

##</code><code>##

s/&((?:(#\d+|0x[\da-f]+)|([a-z0-9]+));?)?/
  $2 ? "&$2;"  # numerical
     : $3 && $isname{$3} ? ($3 eq 'apos' ? "&#39;" : "&$3;")  # named
                         : ($1 ? "&amp;$1" : "&amp;")  # not an entity
/gie;