escape sequence

Some characters cannot be included in [[literal_string?]]s, because they are [[nonprintable?]] or [[control_character?]]s, or characters that affect [[delimit?]]ation of the strings, such as [[quotation_mark?]]s. These characters can be inserted by using an *escape sequence* (known as *literal character notation*).

The backslash symbol can be used to insert literal characters into a string

An *escape sequence* consists of a backslash symbol followed by a character or set of characters used to represent the literal character using a representation encoding.

Representation of nonprintable and control characters

Escape sequences can be used to represent [[nonprintable?]] and [[control_character?]]s, such as [[tab?]] or [[newline?]] characters. The example shows a [[newline?]] character being represented by an escape sequence in the middle of a [[literal_string?]]:

print "first line \n second line" # The \n represents a newline character in a string

The above produces the following output:

first line second line

Representation of doublequote marks

The [[doublequote?]] symbol is used to [[delimit?]] the beginning or end of a string. This means that a [[doublequote?]] could not be used within the string, unless it is escaped by using a backslash prefix, or the string is [[delimit?]]ed using an alternative delimiter.

Representation of the backslash symbol

The backslash symbol is another character that cannot be included in an [[interpolated?]] string. This is because the backslash symbol is used to mark the beginning of an escape sequence. In order to represent the backslash symbol it is necessary to use a [[doublebackslash?]] within the string:

print "There is only one slash (
) printed here.";

Literal character representation

The following literal character representations are available by using the backslash symbol:

\a bell
\b backspace
\e escape
\f formfeed
\n newline
\r carriage return
\t tab
\v vertical tab

Literal characters can be represented by using their ASCII numeric codes

Literal characters can be inserted into strings by using their ASCII numeric codes in the following notation:

\ddd dd is an octal value
\xhh hh is a hexadecimal value