The double-quote is used to begin and end a string. When a double-quote is encountered, characters are read from the input stream and accumulated until another double-quote is encountered. If a single escape character is seen, the single escape character is discarded, the next character is accumulated, and accumulation continues. The accumulated characters up to but not including the matching double-quote are made into a simple string and returned. It is implementation-dependent which attributes of the accumulated characters are removed in this process.
Examples of the use of the double-quote character are in the next figure.
"Foo" ;A string with three characters in it "" ;An empty string "\"APL\\360?\" he cried." ;A string with twenty characters "|x| = |-x|" ;A ten-character string
Figure 2-18. Examples of the use of double-quote
Note that to place a single escape character or a double-quote into a string, such a character must be preceded by a single escape character. Note, too, that a multiple escape character need not be quoted by a single escape character within a string.
For information on how the Lisp printer prints strings, see Section 18.104.22.168 (Printing Strings).