1.3.2.2 Comments

There are two ways to insert comments into a Yorick program. These are the C style /* ... */ and the C++ style //:

// C++ style comments begin with // (anywhere on a line) // and end at the end of that line. E = m*c^2; /* C style comments begin with slash-star, and do not end until start-slash, even if that is several lines later. */ /* C style comments need not annotate a single line. * You should pick a comment style which makes your * code attractive and easy to read. */ F = m*a; // Here is another C++ style comment... divE = 4*pi*rho; /* ... and a final C style comment. */

I strongly recommend C++ style comments when you "comment out" a sequence of Yorick statements. C style comments do not nest properly, so you can't comment out a series of lines which contain comments:

/* E = m*c^2; /* ERROR -- this ends the outer comment --> */ F = m*a */ <-- then this causes a syntax error

The C++ style not only works correctly; it also makes it more obvious that the lines in question are comments:

// E = m*c^2; /* Any kind of comment could go here. */ // F = m*a;

Yorick recognizes one special comment: If the first line of an include file begins with #!, Yorick ignores that line. This allows Yorick include scripts to be executable on UNIX systems supporting the "pound bang" convention:

#!/usr/local/bin/yorick -batch /* If this file has execute permission, UNIX will use Yorick to * execute it. The Yorick function get_argv can be used to accept * command line arguments (see help, get_argv). You might want * to use -i instead of -batch on the first line. Read the help * on process_argv and batch for more information. */ write, "The square root of pi is", sqrt(pi); quit;