indent!(amount, indent_string=nil, indent_empty_lines=false)
public
Same as indent, except it indents the receiver in-place.
Returns the indented string, or nil if there was nothing to indent.
# File activesupport/lib/active_support/core_ext/string/indent.rb, line 5
def indent!(amount, indent_string=nil, indent_empty_lines=false)
indent_string = indent_string || self[/^[ \t]/] || ' '
re = indent_empty_lines ? /^/ : /^(?!$)/
gsub!(re, indent_string * amount)
end