Input from Character Streams

CLtL2 Reference 

function READ : (&optional (stream *standard-input*) (eof-error-p t) (eof-value :eof))
Returns FORM if read was successful.
Returns the values NIL :ERROR if there was a reader error.
Returns the values EOF-VALUE :ERROR if EOF-ERROR-P is nil and EOF occurs.
Causes an error if EOF-ERROR-P is not nil and EOF occurs.

 

Differences from Common Lisp:
Numbers are only read in decimal notation with no specified radix.
No character modifiers: only standard chars plus specials like Space, Return etc.
The || notation and \ syntax for symbols are not supported. 

function READ-LINE : (&optional (stream *standard-input*) (eof-error-p t) (eof-value :eof)) 

function READ-CHAR : (&optional (stream *standard-input*) (eof-error-p t) (eof-value :eof)) 

function UNREAD-CHAR : (char &optional (stream *standard-input*)) 

function READ-FROM-STRING : (string &optional (eof-error-p t) (eof-value :eof) (start 0) end)
Returns the values FORM NEW-START if read was successful.
Returns the values NIL :ERROR if there was a reader error.
Returns the values EOF-VALUE :ERROR if EOF-ERROR-P is nil and EOF occurs.
Causes an error if EOF-ERROR-P is not nil and EOF occurs.
Returns a second value which is an integer indicating the position in the string to
start reading from again or :ERROR if there was some kind of reader error.