Add @ as an allowable character in command names

latexdiff

@@ -33,6 +33,9 @@
 # Version 1.2.1a
 #    - bug fix: deleted figures when endfloat package was activated
 #    - bug fix: alignat environment now always processed correctly (fix issues #65)
+#    - bug fix: avoid processing of commands as potential files in routine init_regex_arr (fix issue #70 )
+#    - minimal feature enhancement: treat '@' as allowed character in commands (strictly speaking requires prior \makeatletter statement, but always assuming it to be 
+@       a letter if it is part of a command name will usually lead to the correct behaviour (see http://tex.stackexchange.com/questions/346651/latexdiff-and-let)
 #
 # Version 1.2.0:
 #    - highlight new and deleted figures
@@ -630,7 +633,7 @@ push(@SAFECMDLIST, qr/^QLEFTBRACE$/, qr/^QRIGHTBRACE$/);
 ### standard $cmdoptseq without intervening spaces
 ###pre-0.3  my $cmdoptseq='\\\\[\w\d\*]+(?:\['.$brat0.'\]|\{'. $pat_n . '\}|\(' . $coords .'\))*';
 ###  my $cmdoptseq='\\\\[\w\d\*]+'.$extraspace.'(?:(?:\['.$brat0.'\]|\{'. $pat_n . '\}|\(' . $coords .'\))'.$extraspace.')*';
-  my $cmdoptseq='\\\\[\w\d\*]+'.$extraspace.'(?:(?:<'.$abrat0.'>|\['.$brat0.'\]|\{'. $pat_n . '\}|\(' . $coords .'\))'.$extraspace.')*';
+  my $cmdoptseq='\\\\[\w\d@\*]+'.$extraspace.'(?:(?:<'.$abrat0.'>|\['.$brat0.'\]|\{'. $pat_n . '\}|\(' . $coords .'\))'.$extraspace.')*';
 ###pre-0.3  my $oneletcmd='(?:\\\\.|[_\^])(?:\['.$brat0.'\]|\{'. $pat_n . '\})*';
   my $backslashnl='\\\\\n';
   my $oneletcmd='\\\\.\*?(?:\['.$brat0.'\]|\{'. $pat_n . '\})*';