The number of spaces to indent the first line of a paragraph. The value provided is silently converted to a positive integer value.

                           columns
<-------------------------------------------------------------->
<-----------><------><---------------------------><------------>
 left margin  INDENT  text is formatted into here  right margin

Source Code

# File action_mailer/vendor/text-format-0.6.3/text/format.rb, line 266
def first_indent=(f)
  @first_indent = posint(f)
end