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- XLISP: An Experimental Object Oriented Language
-
- Version 1.4
-
- January 1, 1985
-
-
- by
- David Betz (Betz@harvard.arpa)
- 114 Davenport Ave.
- Manchester, NH 03103
-
- (603) 625-4691 (home)
-
-
-
- XLISP: An Experimental Object Oriented Language Page 2
- TABLE OF CONTENTS
-
-
- 1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . 3
- 2.0 A NOTE FROM THE AUTHOR . . . . . . . . . . . . . . . 4
- 3.0 XLISP COMMAND LOOP . . . . . . . . . . . . . . . . . 5
- 4.0 BREAK COMMAND LOOP . . . . . . . . . . . . . . . . . 6
- 5.0 DATA TYPES . . . . . . . . . . . . . . . . . . . . . 7
- 6.0 THE EVALUATOR . . . . . . . . . . . . . . . . . . . 8
- 7.0 LEXICAL CONVENTIONS . . . . . . . . . . . . . . . . 9
- 8.0 OBJECTS . . . . . . . . . . . . . . . . . . . . . 10
- 9.0 SYMBOLS . . . . . . . . . . . . . . . . . . . . . 13
- 10.0 EVALUATION FUNCTIONS . . . . . . . . . . . . . . . 14
- 11.0 SYMBOL FUNCTIONS . . . . . . . . . . . . . . . . . 15
- 12.0 PROPERTY LIST FUNCTIONS . . . . . . . . . . . . . 17
- 13.0 LIST FUNCTIONS . . . . . . . . . . . . . . . . . . 18
- 14.0 DESTRUCTIVE LIST FUNCTIONS . . . . . . . . . . . . 21
- 15.0 PREDICATE FUNCTIONS . . . . . . . . . . . . . . . 22
- 16.0 CONTROL FUNCTIONS . . . . . . . . . . . . . . . . 24
- 17.0 LOOPING FUNCTIONS . . . . . . . . . . . . . . . . 25
- 18.0 THE PROGRAM FEATURE . . . . . . . . . . . . . . . 26
- 19.0 DEBUGGING AND ERROR HANDLING . . . . . . . . . . . 27
- 20.0 ARITHMETIC FUNCTIONS . . . . . . . . . . . . . . . 28
- 21.0 BITWISE LOGICAL FUNCTIONS . . . . . . . . . . . . 29
- 22.0 RELATIONAL FUNCTIONS . . . . . . . . . . . . . . . 30
- 23.0 STRING FUNCTIONS . . . . . . . . . . . . . . . . . 31
- 24.0 INPUT/OUTPUT FUNCTIONS . . . . . . . . . . . . . . 32
- 25.0 FILE I/O FUNCTIONS . . . . . . . . . . . . . . . . 33
- 26.0 SYSTEM FUNCTIONS . . . . . . . . . . . . . . . . . 34
-
-
-
- XLISP: An Experimental Object Oriented Language Page 3
- INTRODUCTION
-
-
- 1.0 INTRODUCTION
-
- XLISP is an experimental programming language combining some
- of the features of LISP with an object oriented extension
- capability. It was implemented to allow experimentation
- with object oriented programming on small computers. There
- are currently implementations running on the PDP-11 under
- UNIX V7, on the VAX-11 under VAX/VMS and Berkeley VAX/UNIX,
- and on the 8088/8086 under CP/M-86 or MS-DOS. A version is
- currently being developed for the 68000 under CP/M-68K and
- for the Apple Macintosh. It is completely written in the
- programming language 'C' and is easily extended with user
- written built-in functions and classes. It is available in
- source form free of charge to non-commercial users.
- Prospective commercial users should contact the author for
- permission to use XLISP.
-
- Many traditional LISP functions are built into XLISP. In
- addition, XLISP defines the objects 'Object' and 'Class' as
- primitives. 'Object' is the only class that has no
- superclass and hence is the root of the class heirarchy
- tree. 'Class' is the class of which all classes are
- instances (it is the only object that is an instance of
- itself).
-
- This document is intended to be a brief description of
- XLISP. It assumes some knowledge of LISP and some
- understanding of the concepts of object oriented
- programming.
-
- Version 1.2 of XLISP differs from version 1.1 in several
- ways. It supports many more Lisp functions. Also, many
- version 1.1 functions have been renamed and/or changed
- slightly to follow traditional Lisp usage. One of the most
- frequently reported problems in version 1.1 resulted from
- many functions being named after their equivilent functions
- in the C language. This turned out to be confusing for
- people who were trying to learn XLISP using traditional LISP
- texts as references. Version 1.2 renames these functions to
- be compatible with more traditional dialects of LISP.
- Version 1.3 introduces many new LISP functions and moves
- closer to the goal of being compatible with the Common Lisp
- standard. Version 1.4 introduces user error handling and
- breakpoint support as well as more Common Lisp compatible
- functions.
-
- A recommended text for learning LISP programming is the book
- "LISP" by Winston and Horn and published by Addison Wesley.
- The first edition of this book is based on MacLisp and the
- second edition is based on Common Lisp. Future versions of
- XLISP will continue to migrate towards compatibility with
- Common Lisp.
-
-
-
- XLISP: An Experimental Object Oriented Language Page 4
- A NOTE FROM THE AUTHOR
-
-
- 2.0 A NOTE FROM THE AUTHOR
-
- If you have any problems with XLISP, feel free to contact me
- for help or advice. Please remember that since XLISP is
- available in source form in a high level language, many
- users have been making versions available on a variety of
- machines. If you call to report a problem with a specific
- version, I may not be able to help you if that version runs
- on a machine to which I don't have access. Please have the
- version number of the version that you are running readily
- accessible before calling me.
-
- If you find a bug in XLISP, first try to fix the bug
- yourself using the source code provided. If you are
- successful in fixing the bug, send the bug report along with
- the fix to me. If you don't have access to a C compiler or
- are unable to fix a bug, please send the bug report to me
- and I'll try to fix it.
-
- Any suggestions for improvements will be welcomed. Feel
- free to extend the language in whatever way suits your
- needs. However, PLEASE DO NOT RELEASE ENHANCED VERSIONS
- WITHOUT CHECKING WITH ME FIRST!! I would like to be the
- clearing house for new features added to XLISP. If you want
- to add features for your own personal use, go ahead. But,
- if you want to distribute your enhanced version, contact me
- first. Please remember that the goal of XLISP is to provide
- a language to learn and experiment with LISP and object
- oriented programming on small computers.
-
-
-
- XLISP: An Experimental Object Oriented Language Page 5
- XLISP COMMAND LOOP
-
-
- 3.0 XLISP COMMAND LOOP
-
- When XLISP is started, it first tries to load "init.lsp"
- from the default directory. It then loads any files named
- as parameters on the command line (after appending ".lsp" to
- their names). It then issues the following prompt:
-
- >
-
- This indicates that XLISP is waiting for an expression to be
- typed. When an incomplete expression has been typed (one
- where the left and right parens don't match) XLISP changes
- its prompt to:
-
- n>
-
- where n is an integer indicating how many levels of left
- parens remain unclosed.
-
- When a complete expression has been entered, XLISP attempts
- to evaluate that expression. If the expression evaluates
- successfully, XLISP prints the result of the evaluation and
- then returns to the initial prompt waiting for another
- expression to be typed.
-
- Input can be aborted at any time by typing the CONTROL-G key
- (it may be necessary to follow CONTROL-G by RETURN).
-
-
-
- XLISP: An Experimental Object Oriented Language Page 6
- BREAK COMMAND LOOP
-
-
- 4.0 BREAK COMMAND LOOP
-
- When XLISP encounters an error while evaluating an
- expression, it attempts to handle the error in the following
- way:
-
- If the symbol '*breakenable*' is true, the message
- corresponding to the error is printed. If the error is
- correctable, the correction message is printed. If the
- symbol '*tracenable*' is true, a trace back is printed. The
- number of entries printed depends on the value of the symbol
- '*tracelimit*'. If this symbol is set to something other
- than a number, the entire trace back stack is printed.
- XLISP then enters a read/eval/print loop to allow the user
- to examine the state of the interpreter in the context of
- the error. This loop differs from the normal top-leval
- read/eval/print loop in that if the user types the symbol
- 'continue' XLISP will continue from a correctable error. If
- the user types the symbol 'quit' XLISP will abort the break
- loop and return to the top level or the next lower numbered
- break loop. When in a break loop, XLISP prefixes the break
- level to the normal prompt.
-
- If the symbol '*breakenable*' is nil, XLISP looks for a
- surrounding errset function. If one is found, XLISP
- examines the value of the print flag. If this flag is true,
- the error message is printed. In any case, XLISP causes the
- errset function call to return nil.
-
- If there is no surrounding errset function, XLISP prints the
- error message and returns to the top level.
-
-
-
- XLISP: An Experimental Object Oriented Language Page 7
- DATA TYPES
-
-
- 5.0 DATA TYPES
-
- There are several different data types available to XLISP
- programmers.
-
-
- o lists
-
- o symbols
-
- o strings
-
- o integers
-
- o objects
-
- o file pointers
-
- o subrs/fsubrs (built-in functions)
-
- Another data type is the stream. A stream is a list node
- whose car points to the head of a list of integers and whose
- cdr points to the last list node of the list. An empty
- stream is a list node whose car and cdr are nil. Each of
- the integers in the list represents a character in the
- stream. When a character is read from a stream, the first
- integer from the head of the list is removed and returned.
- When a character is written to a stream, the integer
- representing the character code of the character is appended
- to the end of the list. When a function indicates that it
- takes an input source as a parameter, this parameter can
- either be an input file pointer or a stream. Similarly,
- when a function indicates that it takes an output sink as a
- parameter, this parameter can either be an output file
- pointer or a stream.
-
-
-
- XLISP: An Experimental Object Oriented Language Page 8
- THE EVALUATOR
-
-
- 6.0 THE EVALUATOR
-
- The process of evaluation in XLISP:
-
- o Integers, strings, objects, file pointers, and
- subrs evaluate to themselves
-
- o Symbols evaluate to the value associated with their
- current binding
-
- o Lists are evaluated by evaluating the first element
- of the list
-
- o If it evaluates to a subr, the remaining list
- elements are evaluated and the subr is called
- with these evaluated expressions as arguments.
-
- o If it evaluates to an fsubr, the fsubr is
- called using the remaining list elements as
- arguments (they are evaluated by the subr
- itself if necessary)
-
- o If it evaluates to a list and the car of the
- list is 'lambda', the remaining list elements
- are evaluated and the resulting expressions are
- bound to the formal arguments of the lambda
- expression. The body of the function is
- executed within this new binding environment.
-
- o If it evaluates to a list and the car of the
- list is 'macro', the remaining list elements
- are bound to the formal arguments of the macro
- expression. The body of the function is
- executed within this new binding environment.
- The result of this evaluation is considered the
- macro expansion. This result is then evaluated
- in place of the original expression.
-
- o If it evaluates to an object, the second list
- element is evaluated and used as a message
- selector. The message formed by combining the
- selector with the values of the remaining list
- elements is sent to the object.
-
-
-
-
-
- XLISP: An Experimental Object Oriented Language Page 9
- LEXICAL CONVENTIONS
-
-
- 7.0 LEXICAL CONVENTIONS
-
- The following conventions are followed when entering XLISP
- programs:
-
- Comments in XLISP code begin with a semi-colon character and
- continue to the end of the line.
-
- Symbol names in XLISP can consist of any sequence of
- non-blank printable characters except the following:
-
- ( ) ' ` , " ;
-
- Upper and lower case characters are distinct. The symbols
- 'CAR' and 'car' are not the same. The names of all built-in
- functions are in lower case. The names of all built-in
- objects are lower case with an initial capital. Symbol
- names must not begin with a digit.
-
- Integer literals consist of a sequence of digits optionally
- beginning with a '+' or '-'. The range of values an integer
- can represent is limited by the size of a C 'int' on the
- machine that XLISP is running on.
-
- Literal strings are sequences of characters surrounded by
- double quotes. Within quoted strings the '\' character is
- used to allow non-printable characters to be included. The
- codes recognized are:
-
- \\ means the character '\'
- \n means newline
- \t means tab
- \r means return
- \e means escape
- \nnn means the character whose octal code is nnn
-
- XLISP defines several useful read macros:
-
- '<expr> == (quote <expr>)
- #'<expr> == (function <expr>)
- `<expr> == (backquote <expr>)
- ,<expr> == (comma <expr>)
- ,@<expr> == (comma-at <expr>)
-
-
-
- XLISP: An Experimental Object Oriented Language Page 10
- OBJECTS
-
-
- 8.0 OBJECTS
-
- Definitions:
-
- o selector - a symbol used to select an appropriate
- method
-
- o message - a selector and a list of actual arguments
-
- o method - the code that implements a message
-
- Since XLISP was created to provide a simple basis for
- experimenting with object oriented programming, one of the
- primitive data types included was 'object'. In XLISP, an
- object consists of a data structure containing a pointer to
- the object's class as well as a list containing the values
- of the object's instance variables.
-
- Officially, there is no way to see inside an object (look at
- the values of its instance variables). The only way to
- communicate with an object is by sending it a message. When
- the XLISP evaluator evaluates a list the value of whose
- first element is an object, it interprets the value of the
- second element of the list (which must be a symbol) as the
- message selector. The evaluator determines the class of the
- receiving object and attempts to find a method corresponding
- to the message selector in the set of messages defined for
- that class. If the message is not found in the object's
- class and the class has a super-class, the search continues
- by looking at the messages defined for the super-class.
- This process continues from one super-class to the next
- until a method for the message is found. If no method is
- found, an error occurs.
-
- When a method is found, the evaluator binds the receiving
- object to the symbol 'self', binds the class in which the
- method was found to the symbol 'msgclass', and evaluates the
- method using the remaining elements of the original list as
- arguments to the method. These arguments are always
- evaluated prior to being bound to their corresponding formal
- arguments. The result of evaluating the method becomes the
- result of the expression.
-
-
-
- XLISP: An Experimental Object Oriented Language Page 11
- OBJECTS
-
-
- Classes:
-
- Object THE TOP OF THE CLASS HEIRARCHY
-
- Messages:
-
- show SHOW AN OBJECT'S INSTANCE VARIABLES
- returns the object
-
- class RETURN THE CLASS OF AN OBJECT
- returns the class of the object
-
- isnew THE DEFAULT OBJECT INITIALIZATION ROUTINE
- returns the object
-
- sendsuper <sel> [<args>...] SEND SUPERCLASS A MESSAGE
- <sel> the message selector
- <args> the message arguments
- returns the result of sending the message
-
-
-
- XLISP: An Experimental Object Oriented Language Page 12
- OBJECTS
-
-
- Class THE CLASS OF ALL OBJECT CLASSES (including itself)
-
- Messages:
-
- new CREATE A NEW INSTANCE OF A CLASS
- returns the new class object
-
- isnew [<scls>] INITIALIZE A NEW CLASS
- <scls> the superclass
- returns the new class object
-
- answer <msg> <fargs> <code> ADD A MESSAGE TO A CLASS
- <msg> the message symbol
- <fargs> the formal argument list
- this list is of the form:
- (<farg>...
- [&optional <oarg>...]
- [&rest <rarg>]
- [&aux <aux>...])
- where
- <farg> a formal argument
- <oarg> an optional argument (default is nil)
- <rarg> bound to the rest of the arguments
- <aux> a auxiliary variable (set to nil)
- <code> a list of executable expressions
- returns the object
-
- ivars <vars> DEFINE THE LIST OF INSTANCE VARIABLES
- <vars> the list of instance variable symbols
- returns the object
-
- cvars <vars> DEFINE THE LIST OF CLASS VARIABLES
- <vars> the list of class variable symbols
- returns the object
-
-
- When a new instance of a class is created by sending the
- message 'new' to an existing class, the message 'isnew'
- followed by whatever parameters were passed to the 'new'
- message is sent to the newly created object.
-
- When a new class is created by sending the 'new' message to
- the object 'Class', an optional parameter may be specified
- indicating the superclass of the new class. If this
- parameter is omitted, the new class will be a subclass of
- 'Object'. A class inherits all instance variables, class
- variables, and methods from its super-class.
-
-
-
- XLISP: An Experimental Object Oriented Language Page 13
- SYMBOLS
-
-
- 9.0 SYMBOLS
-
-
- o self - the current object (within a message
- context)
-
- o msgclass - the class in which the current method
- was found
-
- o *oblist* - the object list
-
- o *keylist* - the keyword list
-
- o *standard-input* - the standard input file
-
- o *standard-output* - the standard output file
-
- o *breakenable* - flag controlling entering the break
- loop on errors
-
- o *tracenable* - flag controlling trace back printout
- on errors and breaks
-
- o *tracelimit* - maximum number of levels of trace
- back information printed on errors and breaks
-
- o *evalhook* - user substitute for the evaluator
- function
-
- o *applyhook* - (not yet implemented)
-
- o *unbound* - indicator for unbound symbols
-
-
-
-
- XLISP: An Experimental Object Oriented Language Page 14
- EVALUATION FUNCTIONS
-
-
- 10.0 EVALUATION FUNCTIONS
-
- (eval <expr>) EVALUATE AN XLISP EXPRESSION
- <expr> the expression to be evaluated
- returns the result of evaluating the expression
-
- (apply <fun> <args>) APPLY A FUNCTION TO A LIST OF ARGUMENTS
- <fun> the function to apply (or function symbol)
- <args> the argument list
- returns the result of applying the function to the argument list
-
- (funcall <fun> <arg>...) CALL A FUNCTION WITH ARGUMENTS
- <fun> the function to call (or function symbol)
- <arg> arguments to pass to the function
- returns the result of calling the function with the arguments
-
- (quote <expr>) RETURN AN EXPRESSION UNEVALUATED
- <expr> the expression to be quoted (quoted)
- returns <expr> unevaluated
-
- (function <expr>) QUOTE A FUNCTION (THIS IS THE SAME AS QUOTE)
- <expr> the function to be quoted (quoted)
- returns <expr> unevaluated
-
- (backquote <expr>) FILL IN A TEMPLATE
- <expr> the template
- returns a copy of the template with comma and comma-at expressions
- expanded (see the Common Lisp reference manual)
-
-
-
- XLISP: An Experimental Object Oriented Language Page 15
- SYMBOL FUNCTIONS
-
-
- 11.0 SYMBOL FUNCTIONS
-
- (set <sym> <expr>) SET THE VALUE OF A SYMBOL
- <sym> the symbol being set
- <expr> the new value
- returns the new value
-
- (setq [<sym> <expr>]...) SET THE VALUE OF A SYMBOL
- <sym> the symbol being set (quoted)
- <expr> the new value
- returns the new value
-
- (setf [<place> <expr>]...) SET THE VALUE OF A FIELD
- <place> the field specifier (quoted):
- <sym> set the value of a symbol
- (car <expr>) set the car of a list node
- (cdr <expr>) set the cdr of a list node
- (get <sym> <prop>) set the value of a property
- (symbol-value <sym>) set the value of a symbol
- (symbol-plist <sym>) set the property list of a symbol
- <value> the new value
- returns the new value
-
- (defun <sym> <fargs> <expr>...) DEFINE A FUNCTION
- (defmacro <sym> <fargs> <expr>...) DEFINE A MACRO
- <sym> symbol being defined (quoted)
- <fargs> list of formal arguments (quoted)
- this list is of the form:
- (<farg>...
- [&optional <oarg>...]
- [&rest <rarg>]
- [&aux <aux>...])
- where
- <farg> is a formal argument
- <oarg> is an optional argument (default is nil)
- <rarg> bound to the rest of the arguments
- <aux> is an auxiliary variable (set to nil)
- <expr> expressions constituting the body of the
- function (quoted)
- returns the function symbol
-
- (gensym [<tag>]) GENERATE A SYMBOL
- <tag> string or number
- returns the new symbol
-
- (intern <pname>) MAKE AN INTERNED SYMBOL
- <pname> the symbol's print name string
- returns the new symbol
-
- (make-symbol <pname>) MAKE AN UNINTERNED SYMBOL
- <pname> the symbol's print name string
- returns the new symbol
-
-
-
- XLISP: An Experimental Object Oriented Language Page 16
- SYMBOL FUNCTIONS
-
-
- (symbol-name <sym>) GET THE PRINT NAME OF A SYMBOL
- <sym> the symbol
- returns the symbol's print name
-
- (symbol-value <sym>) GET THE VALUE OF A SYMBOL
- <sym> the symbol
- returns the symbol's value
-
- (symbol-plist <sym>) GET THE PROPERTY LIST OF A SYMBOL
- <sym> the symbol
- returns the symbol's property list
-
-
-
- XLISP: An Experimental Object Oriented Language Page 17
- PROPERTY LIST FUNCTIONS
-
-
- 12.0 PROPERTY LIST FUNCTIONS
-
- (get <sym> <prop>) GET THE VALUE OF A PROPERTY
- <sym> the symbol
- <prop> the property symbol
- returns the property value or nil
-
- (remprop <prop> <sym>) REMOVE A PROPERTY
- <sym> the symbol
- <prop> the property symbol
- returns nil
-
-
-
- XLISP: An Experimental Object Oriented Language Page 18
- LIST FUNCTIONS
-
-
- 13.0 LIST FUNCTIONS
-
- (car <expr>) RETURN THE CAR OF A LIST NODE
- <expr> the list node
- returns the car of the list node
-
- (cdr <expr>) RETURN THE CDR OF A LIST NODE
- <expr> the list node
- returns the cdr of the list node
-
- (caar <expr>) == (car (car <expr>))
- (cadr <expr>) == (car (cdr <expr>))
- (cdar <expr>) == (cdr (car <expr>))
- (cddr <expr>) == (cdr (cdr <expr>))
-
- (cons <expr1> <expr2>) CONSTRUCT A NEW LIST NODE
- <expr1> the car of the new list node
- <expr2> the cdr of the new list node
- returns the new list node
-
- (list <expr>...) CREATE A LIST OF VALUES
- <expr> expressions to be combined into a list
- returns the new list
-
- (append <expr>...) APPEND LISTS
- <expr> lists whose elements are to be appended
- returns the new list
-
- (reverse <expr>) REVERSE A LIST
- <expr> the list to reverse
- returns a new list in the reverse order
-
- (last <list>) RETURN THE LAST LIST NODE OF A LIST
- <list> the list
- returns the last list node in the list
-
- (member <expr> <list> [<key> <test>]) FIND AN EXPRESSION IN A LIST
- <expr> the expression to find
- <list> the list to search
- <key> the keyword :test or :test-not
- <test> the test function (defaults to eql)
- returns the remainder of the list starting with the expression
-
- (assoc <expr> <alist> [<key> <test>]) FIND AN EXPRESSION IN AN A-LIST
- <expr> the expression to find
- <alist> the association list
- <key> the keyword :test or :test-not
- <test> the test function (defaults to eql)
- returns the alist entry or nil
-
-
-
- XLISP: An Experimental Object Oriented Language Page 19
- LIST FUNCTIONS
-
-
- (remove <expr> <list> [<key> <test>]) REMOVE AN EXPRESSION FROM A LIST
- <expr> the expression to delete
- <list> the list
- <key> the keyword :test or :test-not
- <test> the test function (defaults to eql)
- returns the list with the matching expressions deleted
-
- (length <expr>) FIND THE LENGTH OF A LIST
- <expr> the list
- returns the length of the list
-
- (nth <n> <list>) RETURN THE NTH ELEMENT OF A LIST
- <n> the number of the element to return (zero origin)
- <list> the list
- returns the nth element or nil if the list isn't that long
-
- (nthcdr <n> <list>) RETURN THE NTH CDR OF A LIST
- <n> the number of the element to return (zero origin)
- <list> the list
- returns the nth cdr or nil if the list isn't that long
-
- (mapc <fcn> <list1>...<listn>) APPLY FUNCTION TO SUCCESSIVE CARS
- <fcn> the function or function name
- <list1..n> a list for each argument of the function
- returns the first list of arguments
-
- (mapcar <fcn> <list1>...<listn>) APPLY FUNCTION TO SUCCESSIVE CARS
- <fcn> the function or function name
- <list1..n> a list for each argument of the function
- returns the list of values returned by each function invocation
-
- (mapl <fcn> <list1>...<listn>) APPLY FUNCTION TO SUCCESSIVE CDRS
- <fcn> the function or function name
- <list1..n> a list for each argument of the function
- returns the first list of arguments
-
- (maplist <fcn> <list1>...<listn>) APPLY FUNCTION TO SUCCESSIVE CDRS
- <fcn> the function or function name
- <list1..n> a list for each argument of the function
- returns the list of values returned by each function invocation
-
-
-
- XLISP: An Experimental Object Oriented Language Page 20
- LIST FUNCTIONS
-
-
- (subst <to> <from> <expr> [<key> <test>]) SUBSTITUTE EXPRESSIONS
- <to> the new expression
- <from> the old expression
- <expr> the expression in which to do the substitutions
- <key> the keyword :test or :test-not
- <test> the test function (defaults to eql)
- returns the expression with substitutions
-
- (sublis <alist> <expr> [<key> <test>]) SUBSTITUTE USING AN A-LIST
- <alist> the association list
- <expr> the expression in which to do the substitutions
- <key> the keyword :test or :test-not
- <test> the test function (defaults to eql)
- returns the expression with substitutions
-
-
-
- XLISP: An Experimental Object Oriented Language Page 21
- DESTRUCTIVE LIST FUNCTIONS
-
-
- 14.0 DESTRUCTIVE LIST FUNCTIONS
-
- (rplaca <list> <expr>) REPLACE THE CAR OF A LIST NODE
- <list> the list node
- <expr> the new value for the car of the list node
- returns the list node after updating the car
-
- (rplacd <list> <expr>) REPLACE THE CDR OF A LIST NODE
- <list> the list node
- <expr> the new value for the cdr of the list node
- returns the list node after updating the cdr
-
- (nconc <list>...) DESTRUCTIVELY CONCATENATE LISTS
- <list> lists to concatenate
- returns the result of concatenating the lists
-
- (delete <expr> <list> [<key> <test>]) DELETE AN EXPRESSION FROM A LIST
- <expr> the expression to delete
- <list> the list
- <key> the keyword :test or :test-not
- <test> the test function (defaults to eql)
- returns the list with the matching expressions deleted
-
-
-
- XLISP: An Experimental Object Oriented Language Page 22
- PREDICATE FUNCTIONS
-
-
- 15.0 PREDICATE FUNCTIONS
-
- (atom <expr>) IS THIS AN ATOM?
- <expr> the expression to check
- returns t if the value is an atom, nil otherwise
-
- (symbolp <expr>) IS THIS A SYMBOL?
- <expr> the expression to check
- returns t if the expression is a symbol, nil otherwise
-
- (numberp <expr>) IS THIS A NUMBER?
- <expr> the expression to check
- returns t if the expression is a symbol, nil otherwise
-
- (null <expr>) IS THIS AN EMPTY LIST?
- <expr> the list to check
- returns t if the list is empty, nil otherwise
-
- (not <expr>) IS THIS FALSE?
- <expr> the expression to check
- return t if the expression is nil, nil otherwise
-
- (listp <expr>) IS THIS A LIST?
- <expr> the expression to check
- returns t if the value is a list node or nil, nil otherwise
-
- (consp <expr>) IS THIS A NON-EMPTY LIST?
- <expr> the expression to check
- returns t if the value is a list node, nil otherwise
-
- (boundp <sym>) IS THIS A BOUND SYMBOL?
- <sym> the symbol
- returns t if a value is bound to the symbol, nil otherwise
-
-
-
- XLISP: An Experimental Object Oriented Language Page 23
- PREDICATE FUNCTIONS
-
-
- (minusp <expr>) IS THIS NUMBER NEGATIVE?
- <expr> the number to test
- returns t if the number is negative, nil otherwise
-
- (zerop <expr>) IS THIS NUMBER ZERO?
- <expr> the number to test
- returns t if the number is zero, nil otherwise
-
- (plusp <expr>) IS THIS NUMBER POSITIVE?
- <expr> the number to test
- returns t if the number is positive, nil otherwise
-
- (evenp <expr>) IS THIS NUMBER EVEN?
- <expr> the number to test
- returns t if the number is even, nil otherwise
-
- (oddp <expr>) IS THIS NUMBER ODD?
- <expr> the number to test
- returns t if the number is odd, nil otherwise
-
- (eq <expr1> <expr2>) ARE THE EXPRESSIONS IDENTICAL?
- <expr1> the first expression
- <expr2> the second expression
- returns t if they are equal, nil otherwise
-
- (eql <expr1> <expr2>) ARE THE EXPRESSIONS IDENTICAL?
- (WORKS WITH NUMBERS AND STRINGS)
- <expr1> the first expression
- <expr2> the second expression
- returns t if they are equal, nil otherwise
-
- (equal <expr1> <expr2>) ARE THE EXPRESSIONS EQUAL?
- <expr1> the first expression
- <expr2> the second expression
- returns t if they are equal, nil otherwise
-
-
-
- XLISP: An Experimental Object Oriented Language Page 24
- CONTROL FUNCTIONS
-
-
- 16.0 CONTROL FUNCTIONS
-
- (cond <pair>...) EVALUATE CONDITIONALLY
- <pair> pair consisting of:
- (<pred> <expr>...)
- where
- <pred> is a predicate expression
- <expr> evaluated if the predicate
- is not nil
- returns the value of the first expression whose predicate
- is not nil
-
- (and <expr>...) THE LOGICAL AND OF A LIST OF EXPRESSIONS
- <expr>... the expressions to be ANDed
- returns nil if any expression evaluates to nil,
- otherwise the value of the last expression
- (evaluation of expressions stops after the first
- expression that evaluates to nil)
-
- (or <expr>...) THE LOGICAL OR OF A LIST OF EXPRESSIONS
- <expr>... the expressions to be ORed
- returns nil if all expressions evaluate to nil,
- otherwise the value of the first non-nil expression
- (evaluation of expressions stops after the first
- expression that does not evaluate to nil)
-
- (if <texpr> <expr1> [<expr2>]) EXECUTE EXPRESSIONS CONDITIONALLY
- <texpr> the test expression
- <expr1> the expression to be evaluated if texpr is non-nil
- <expr2> the expression to be evaluated if texpr is nil
- returns the value of the selected expression
-
- (let (<binding>...) <expr>...) BIND SYMBOLS AND EVALUATE EXPRESSIONS
- (let* (<binding>...) <expr>...) LET WITH SEQUENTIAL BINDING
- <binding> the variable bindings each of which is either:
- 1) a symbol (which is initialized to nil)
- 2) a list whose car is a symbol and whose cadr
- is an initialization expression
- <expr>... the expressions to be evaluated
- returns the value of the last expression
-
- (catch <sym> [<expr>]...) EVALUATE EXPRESSIONS AND CATCH THROWS
- <sym> the catch tag
- <expr>... expressions to evaluate
- returns the value of the last expression the throw expression
-
- (throw <sym> [<expr>]) THROW TO A CATCH
- <sym> the catch tag
- <expr> the value for the catch to return (defaults to nil)
- returns never returns
-
-
-
- XLISP: An Experimental Object Oriented Language Page 25
- LOOPING FUNCTIONS
-
-
- 17.0 LOOPING FUNCTIONS
-
- (do ([<binding>]...) (<texpr> [<rexpr>]...) [<expr>]...)
- (do* ([<binding>]...) (<texpr> [<rexpr>]...) [<expr>]...)
- <binding> the variable bindings each of which is either:
- 1) a symbol (which is initialized to nil)
- 2) a list of the form: (<sym> <init> [<step>])
- where:
- <sym> is the symbol to bind
- <init> is the initial value of the symbol
- <step> is a step expression
- <texpr> the termination test expression
- <rexpr>... result expressions (the default is nil)
- <expr>... the body of the loop (treated like an implicit prog)
- returns the value of the last result expression
-
- (dolist (<sym> <expr> [<rexpr>]) [<expr>]...) LOOP THROUGH A LIST
- <sym> the symbol to bind to each list element
- <expr> the list expression
- <rexpr> the result expression (the default is nil)
- <expr>... the body of the loop (treated like an implicit prog)
-
- (dotimes (<sym> <expr> [<rexpr>]) [<expr>]...) LOOP FROM ZERO TO N-1
- <sym> the symbol to bind to each value from 0 to n-1
- <expr> the number of times to loop
- <rexpr> the result expression (the default is nil)
- <expr>... the body of the loop (treated like an implicit prog)
-
-
-
- XLISP: An Experimental Object Oriented Language Page 26
- THE PROGRAM FEATURE
-
-
- 18.0 THE PROGRAM FEATURE
-
- (prog (<binding>...) [<expr>]...) THE PROGRAM FEATURE
- (prog* (<binding>...) [<expr>]...) PROG WITH SEQUENTIAL BINDING
- <binding> the variable bindings each of which is either:
- 1) a symbol (which is initialized to nil)
- 2) a list whose car is a symbol and whose cadr
- is an initialization expression
- <expr> expressions to evaluate or tags (symbols)
- returns nil or the argument passed to the return function
-
- (go <sym>) GO TO A TAG WITHIN A PROG CONSTRUCT
- <sym> the tag (quoted)
- returns never returns
-
- (return [<expr>]) CAUSE A PROG CONSTRUCT TO RETURN A VALUE
- <expr> the value (defaults to nil)
- returns never returns
-
- (prog1 <expr1> [<expr>]...) EXECUTE EXPRESSIONS SEQUENTIALLY
- <expr1> the first expression to evaluate
- <expr>... the remaining expressions to evaluate
- returns the value of the first expression
-
- (prog2 <expr1> <expr2> [<expr>]...) EXECUTE EXPRESSIONS SEQUENTIALLY
- <expr1> the first expression to evaluate
- <expr2> the second expression to evaluate
- <expr>... the remaining expressions to evaluate
- returns the value of the second expression
-
- (progn [<expr>]...) EXECUTE EXPRESSIONS SEQUENTIALLY
- <expr>... the expressions to evaluate
- returns the value of the last expression (or nil)
-
-
-
- XLISP: An Experimental Object Oriented Language Page 27
- DEBUGGING AND ERROR HANDLING
-
-
- 19.0 DEBUGGING AND ERROR HANDLING
-
- (error <emsg> [<arg>]) SIGNAL A NON-CORRECTABLE ERROR
- <emsg> the error message string
- <arg> the argument expression (printed after the message)
- returns never returns
-
- (cerror <cmsg> <emsg> [<arg>]) SIGNAL A CORRECTABLE ERROR
- <cmsg> the continue message string
- <emsg> the error message string
- <arg> the argument expression (printed after the message)
- returns nil when continued from the break loop
-
- (break [<bmsg> [<arg>]]) ENTER A BREAK LOOP
- <bmsg> the break message string (defaults to "**BREAK**")
- <arg> the argument expression (printed after the message)
- returns nil when continued from the break loop
-
- (errset <expr> [<pflag>]) TRAP ERRORS
- <expr> the expression to execute
- <pflag> flag to control printing of the error message
- returns the value of the last expression consed with nil
- or nil on error
-
- (baktrace [<n>]) PRINT N LEVELS OF TRACE BACK INFORMATION
- <n> the number of levels (defaults to all levels)
- returns nil
-
- (evalhook <expr> <ehook> <ahook>) EVALUATE AN EXPRESSION WITH HOOKS
- <expr> the expression to evaluate
- <ehook> the value for *evalhook*
- <ahook> the value for *applyhook*
- returns the result of evaluating the expression
-
-
-
- XLISP: An Experimental Object Oriented Language Page 28
- ARITHMETIC FUNCTIONS
-
-
- 20.0 ARITHMETIC FUNCTIONS
-
- (+ <expr>...) ADD A LIST OF NUMBERS
- <expr>... the numbers
- returns the result of the addition
-
- (- <expr>...) SUBTRACT A LIST OF NUMBERS OR NEGATE A SINGLE NUMBER
- <expr>... the numbers
- returns the result of the subtraction
-
- (* <expr>...) MULTIPLY A LIST OF NUMBERS
- <expr>... the numbers
- returns the result of the multiplication
-
- (/ <expr>...) DIVIDE A LIST OF NUMBERS
- <expr>... the numbers
- returns the result of the division
-
- (1+ <expr>) ADD ONE TO A NUMBER
- <expr> the number
- returns the number plus one
-
- (1- <expr>) SUBTRACT ONE FROM A NUMBER
- <expr> the number
- returns the number minus one
-
- (rem <expr>...) REMAINDER OF A LIST OF NUMBERS
- <expr>... the numbers
- returns the result of the remainder operation
-
- (min <expr>...) THE SMALLEST OF A LIST OF NUMBERS
- <expr>... the expressions to be checked
- returns the smallest number in the list
-
- (max <expr>...) THE LARGEST OF A LIST OF NUMBERS
- <expr>... the expressions to be checked
- returns the largest number in the list
-
- (abs <expr>) THE ABSOLUTE VALUE OF A NUMBER
- <expr> the number
- returns the absolute value of the number
-
-
-
- XLISP: An Experimental Object Oriented Language Page 29
- BITWISE LOGICAL FUNCTIONS
-
-
- 21.0 BITWISE LOGICAL FUNCTIONS
-
- (bit-and <expr>...) THE BITWISE AND OF A LIST OF NUMBERS
- <expr> the numbers
- returns the result of the and operation
-
- (bit-ior <expr...) THE BITWISE INCLUSIVE OR OF A LIST OF NUMBERS
- <expr> the numbers
- returns the result of the inclusive or operation
-
- (bit-xor <expr...) THE BITWISE EXCLUSIVE OR OF A LIST OF NUMBERS
- <expr> the numbers
- returns the result of the exclusive or operation
-
- (bit-not <expr>) THE BITWISE NOT OF A NUMBER
- <expr> the number
- returns the bitwise inversion of number
-
-
-
- XLISP: An Experimental Object Oriented Language Page 30
- RELATIONAL FUNCTIONS
-
-
- 22.0 RELATIONAL FUNCTIONS
-
- The relational functions can be used to compare integers or
- strings. The functions '=' and '/=' can also be used to
- compare other types. The result of these comparisons is
- computed the same way as for 'eq'.
-
- (< <e1> <e2>) TEST FOR LESS THAN
- <e1> the left operand of the comparison
- <e2> the right operand of the comparison
- returns the result of comparing <e1> with <e2>
-
- (<= <e1> <e2>) TEST FOR LESS THAN OR EQUAL TO
- <e1> the left operand of the comparison
- <e2> the right operand of the comparison
- returns the result of comparing <e1> with <e2>
-
- (= <e1> <e2>) TEST FOR EQUAL TO
- <e1> the left operand of the comparison
- <e2> the right operand of the comparison
- returns the result of comparing <e1> with <e2>
-
- (/= <e1> <e2>) TEST FOR NOT EQUAL TO
- <e1> the left operand of the comparison
- <e2> the right operand of the comparison
- returns the result of comparing <e1> with <e2>
-
- (>= <e1> <e2>) TEST FOR GREATER THAN OR EQUAL TO
- <e1> the left operand of the comparison
- <e2> the right operand of the comparison
- returns the result of comparing <e1> with <e2>
-
- (> <e1> <e2>) TEST FOR GREATER THAN
- <e1> the left operand of the comparison
- <e2> the right operand of the comparison
- returns the result of comparing <e1> with <e2>
-
-
-
- XLISP: An Experimental Object Oriented Language Page 31
- STRING FUNCTIONS
-
-
- 23.0 STRING FUNCTIONS
-
- (strcat <expr>...) CONCATENATE STRINGS
- <expr>... the strings to concatenate
- returns the result of concatenating the strings
-
- (strlen <expr>) COMPUTE THE LENGTH OF A STRING
- <expr> the string
- returns the length of the string
-
- (substr <expr> <sexpr> [<lexpr>]) EXTRACT A SUBSTRING
- <expr> the string
- <sexpr> the starting position
- <lexpr> the length (default is rest of string)
- returns substring starting at <sexpr> for <lexpr>
-
- (ascii <expr>) NUMERIC VALUE OF CHARACTER
- <expr> the string
- returns the ascii code of the first character
-
- (chr <expr>) CHARACTER EQUIVALENT OF ASCII VALUE
- <expr> the numeric expression
- returns a one character string whose first character is <expr>
-
- (atoi <expr>) CONVERT AN ASCII STRING TO AN INTEGER
- <expr> the string
- returns the integer value of the string expression
-
- (itoa <expr>) CONVERT AN INTEGER TO AN ASCII STRING
- <expr> the integer
- returns the string representation of the integer value
-
-
-
- XLISP: An Experimental Object Oriented Language Page 32
- INPUT/OUTPUT FUNCTIONS
-
-
- 24.0 INPUT/OUTPUT FUNCTIONS
-
- (read [<source> [<eof>]]) READ AN XLISP EXPRESSION
- <source> the input source (default is standard input)
- <eof> the value to return on end of file (default is nil)
- returns the expression read
-
- (print <expr> [<sink>]) PRINT A LIST OF VALUES ON A NEW LINE
- <expr> the expressions to be printed
- <sink> the output sink (default is standard output)
- returns nil
-
- (prin1 <expr> [<sink>]) PRINT A LIST OF VALUES
- <expr> the expressions to be printed
- <sink> the output sink (default is standard output)
- returns nil
-
- (princ <expr> [<sink>]) PRINT A LIST OF VALUES WITHOUT QUOTING
- <expr> the expressions to be printed
- <sink> the output sink (default is standard output)
- returns nil
-
- (terpri [<sink>]) TERMINATE THE CURRENT PRINT LINE
- <sink> the output sink (default is standard output)
- returns nil
-
- (flatsize <expr>) LENGTH OF PRINTED REPRESENTATION USING PRIN1
- <expr> the expression
- returns the length
-
- (flatc <expr>) LENGTH OF PRINTED REPRESENTATION USING PRINC
- <expr> the expression
- returns the length
-
- (explode <expr>) CHARACTERS IN PRINTED REPRESENTATION USING PRIN1
- <expr> the expression
- returns the list of characters
-
- (explodec <expr>) CHARACTERS IN PRINTED REPRESENTATION USING PRINC
- <expr> the expression
- returns the list of characters
-
- (maknam <list>) BUILD AN UNINTERNED SYMBOL FROM A LIST OF CHARACTERS
- <list> list of characters in symbol name
- returns the symbol
-
- (implode <list>) BUILD AN INTERNED SYMBOL FROM A LIST OF CHARACTERS
- <list> list of characters in symbol name
- returns the symbol
-
-
-
- XLISP: An Experimental Object Oriented Language Page 33
- FILE I/O FUNCTIONS
-
-
- 25.0 FILE I/O FUNCTIONS
-
- (openi <fname>) OPEN AN INPUT FILE
- <fname> the file name string
- returns a file pointer
-
- (openo <fname>) OPEN AN OUTPUT FILE
- <fname> the file name string
- returns a file pointer
-
- (close <fp>) CLOSE A FILE
- <fp> the file pointer
- returns nil
-
- (read-char [<source>]) READ A CHARACTER FROM A FILE OR STREAM
- <source> the input source (default is standard input)
- returns the character (integer)
-
- (peek-char [<flag> [<source>]]) PEEK AT THE NEXT CHARACTER
- <flag> flag for skipping white space (default is nil)
- <source> the input source (default is standard input)
- returns the character (integer)
-
- (write-char <ch> [<sink>]) WRITE A CHARACTER TO A FILE OR STREAM
- <ch> the character to put (integer)
- <sink> the output sink (default is standard output)
- returns the character (integer)
-
- (readline [<source>]) READ A LINE FROM A FILE OR STREAM
- <source> the input source (default is standard input)
- returns the input string
-
-
-
- XLISP: An Experimental Object Oriented Language Page 34
- SYSTEM FUNCTIONS
-
-
- 26.0 SYSTEM FUNCTIONS
-
- (load <fname> [<vflag> [<pflag>]]) LOAD AN XLISP SOURCE FILE
- <fname> the filename string (".lsp" is appended)
- <vflag> the verbose flag (default is t)
- <pflag> the print flag (default is nil)
- returns the filename
-
- (gc) FORCE GARBAGE COLLECTION
- returns nil
-
- (expand <num>) EXPAND MEMORY BY ADDING SEGMENTS
- <num> the number of segments to add
- returns the number of segments added
-
- (alloc <num>) CHANGE NUMBER OF NODES TO ALLOCATE IN EACH SEGMENT
- <num> the number of nodes to allocate
- returns the old number of nodes to allocate
-
- (mem) SHOW MEMORY ALLOCATION STATISTICS
- returns nil
-
- (type <expr>) RETURNS THE TYPE OF THE EXPRESSION
- <expr> the expression to return the type of
- returns nil if the value is nil otherwise one of the symbols:
- SYM for symbols
- OBJ for objects
- LIST for list nodes
- SUBR for subroutine nodes with evaluated arguments
- FSUBR for subroutine nodes with unevaluated arguments
- STR for string nodes
- INT for integer nodes
- FPTR for file pointer nodes
-
- (exit) EXIT XLISP
- returns never returns
-
-