Loading other files

1995/12/01 LATEX provides these commands: 

   \LoadClass        \LoadClassWithOptions
   \RequirePackage   \RequirePackageWithOptions
for using classes or packages inside other classes or packages. We recommend strongly that you use them, rather than the primitive | =| command, for a number of reasons.

Files loaded with | =<filename>| will not be listed in the || list.

If a package is always loaded with |..| or | then, even if its loading is requested several times, it will be loaded only once. By contrast, if it is loaded with | =| then it can be loaded more than once; such an extra loading may waste time and memory and it may produce strange results.

If a package provides option-processing then, again, strange results are possible if the package is | =| rather than loaded by means of | or |..|.

If the package |foo.sty| loads the package |baz.sty| by use of | =baz.sty| then the user will get a warning: 

   LaTeX Warning: You have requested package `foo',
                  but the package provides `baz'.
Thus, for several reasons, using | =| to load packages is not a good idea.

Unfortunately, if you are upgrading the file |myclass.sty| to a class file then you have to make sure that any old files which contain | =myclass.sty| still work.

This was also true for the standard classes (|article|, |book| and |report|), since a lot of existing LATEX 2.09 document styles contain | =article.sty|. The approach which we use to solve this is to provide minimal files |article.sty|, |book.sty| and |report.sty|, which simply load the appropriate class files. ;''

;''For example, |article.sty| contains just the following lines:;''

   \NeedsTeXFormat{LaTeX2e}
   \@obsoletefile{article.sty}{article.cls}
   \LoadClass{article}
;''You may wish to do the same or, if you think that it is safe to do so,;''you may decide to just remove |myclass.sty|.;'';''

;''