Could someone tell me why constant is preferable to #define in the following code?

• constant will work on platforms without cpp (that's the big one for me :-)
• constant is package scoped. #define is not.
• With constant you have access to perl at compile time. With #define you do not.
• Different versions of cpp on different platforms do different things.
• It's unlikely to be much faster, if at all. The constant's are expanded at compile time so there is no run-time cost using either system. Starting up a cpp process may actually slow down your compile time.
• require() will include your code only once, compile in a separate lexical file scope, and in package main by default. #include will not.
• C macros are very much not first class macros IMHO. See Macros, LFSPs and LFMs for more on this.

:-)

---

In reply to Re: C pre-processor in Perl by adrianh
in thread C pre-processor in Perl by dragonchild

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":





---

• Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
• Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
• Read Where should I post X? if you're not absolutely sure you're posting in the right place.
• Please read these before you post! —
  • How do I compose an effective node title?
  • How do I post a question effectively?
  • Markup in the Monastery
• Posts may use any of the Perl Monks Approved HTML tags:

  a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

• You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

  	For:		Use:
  	&		&
  	<		&lt;
  	>		&gt;
  	[		&#91;
  	]		&#93;

• Link using PerlMonks shortcuts! What shortcuts can I use for linking?
• See Writeup Formatting Tips and other pages linked from there for more info.