diff options
| -rw-r--r-- | doc/syntax/miscellaneous.rdoc | 30 | ||||
| -rw-r--r-- | eval.c | 5 |
2 files changed, 34 insertions, 1 deletions
diff --git a/doc/syntax/miscellaneous.rdoc b/doc/syntax/miscellaneous.rdoc index 87ec059ae7..d5cfd3e474 100644 --- a/doc/syntax/miscellaneous.rdoc +++ b/doc/syntax/miscellaneous.rdoc @@ -83,6 +83,36 @@ Using the specific reflection methods such as instance_variable_defined? for instance variables or const_defined? for constants is less error prone than using +defined?+. ++defined?+ handles some regexp global variables specially based on whether +there is an active regexp match and how many capture groups there are: + + /b/ =~ 'a' + defined?($~) # => "global-variable" + defined?($&) # => nil + defined?($`) # => nil + defined?($') # => nil + defined?($+) # => nil + defined?($1) # => nil + defined?($2) # => nil + + /./ =~ 'a' + defined?($~) # => "global-variable" + defined?($&) # => "global-variable" + defined?($`) # => "global-variable" + defined?($') # => "global-variable" + defined?($+) # => nil + defined?($1) # => nil + defined?($2) # => nil + + /(.)/ =~ 'a' + defined?($~) # => "global-variable" + defined?($&) # => "global-variable" + defined?($`) # => "global-variable" + defined?($') # => "global-variable" + defined?($+) # => "global-variable" + defined?($1) # => "global-variable" + defined?($2) # => nil + == +BEGIN+ and +END+ +BEGIN+ defines a block that is run before any other code in the current file. @@ -1996,7 +1996,10 @@ f_current_dirname(VALUE _) * call-seq: * global_variables -> array * - * Returns an array of the names of global variables. + * Returns an array of the names of global variables. This includes + * special regexp global variables such as <tt>$~</tt> and <tt>$+</tt>, + * but does not include the numbered regexp global variables (<tt>$1</tt>, + * <tt>$2</tt>, etc.). * * global_variables.grep /std/ #=> [:$stdin, :$stdout, :$stderr] */ |