I think the reason why Ruby is not so readable is because Ruby has special variables like $$.

$!	latest error message
$@	location of error
$_	string last read by gets
$.	line number last read by interpreter
$&	string last matched by regexp
$~	the last regexp match, as an array of subexpressions
$n	the nth subexpression in the last match (same as $~[n])
$=	case-insensitivity flag
$/	input record separator
$\	output record separator
$0	the name of the ruby script file
$*	the command line arguments
$$	interpreter's process ID
$?	exit status of last executed child process

Ruby programmers who often use these awkward looking special variables may feel comfortable, but I hate that I have to memory the difference between $! and $@. What is the rule to memorize the meanings of these variables? Even worse, some variables names are confusing. For example, Ruby naming convention states that variables starting with $ are global variables, but $_ and $~ are closer to local variables.

Ruby emphasizes the principles of least surprise, but special variables really surprised me. [For those of you who are not familar with the principles of least surprise: Read"Applying the Rule of Least Surprise"  in The Art of Unix Programming written by Eric  Raymond.]

Ruby is a pure objected-oriented language and special variables do not fit well in OO concepts. Why don't we make a Process clsss and define pid and args methods to retrieve process ID and command line arguments instead of ugly $$ and $* variables?