Lisp

1
Lisp

• "List Processing"

2
Lisp history

• John McCarthy developed the basics behind Lisp
  during the 1956 Dartmouth Summer Research Project
  on Artificial Intelligence
• He intended it as an algebraic LISt Processing
  (hence the name) language for artificial
  intelligence work
• He showed how, given a handful of simple
  operators and anotation for functions, you can
  build a whole programming language.

3
Design Goals

• Formalism for developing a theory of computation
• Programming language for numerical and logical
  problems
• Symbolic manipulation of expressions and sentences

4
Characteristics

• LISP was one of the earliest high-level
  programming languages and introduced many ideas
  such as garbage collection, recursive functions,
  symbolic expressions, and dynamic type-checking
• Interest in symbolic computation influenced
  design
• Use of simple machine model
• Attention to theoretical considerations Recursive
  function theory, Lambda calculus

5
Distinctive Characteristics

• Not C, C, Java a chance to think differently
• LISt Processing the ancestor of all
• functional languages
• Lisp is good at handling lists of things, and the
  abstraction level is higher than C/C normally
  allows you to get to.

6
Relative Speeds of 5 language
7
Description of Lisp

• LISP is usually used as an interpreted language.
• The interpreter runs what is known as a
• read- evaluates-print loop.

8
Description of Lisp

• The two most important kinds of objects in LISP
• for you to know about are atoms and lists.
• Atoms are represented as sequences of
• characters of reasonable length. Such as 34
  or join.
• Lists are recursively constructed from atoms
• Such as (a john 34 c3po).
• The interpreter treats any list as containing
  the
• name of a function followed by the arguments
  to
• the function. Such as ( 2 13 45).

9
Defining Lisp Function

• Use defun to define your own functions in LISP.
• (defun ltnamegt ltparameter-listgt ltbodygt)
• Example
• gt(defun square (x) ( x x))
• SQUARE
• gt(square 2)
• 4

10
Example Code

• reverse Format (reverse ltlistgt)
• Reverse returns a list that contains all the
• elements of ltlistgt in reversed order.
• Example
• gt (reverse '(picard riker worf crusher))
• (CRUSHER WORF RIKER PICARD)
• gt (reverse (reverse '(picard riker worf
  crusher)))
• (PICARD RIKER WORF CRUSHER)

11
Resources

• http//faqs.org/faqs/lisp-faq/part2/section-13.htm
  l
• http//www.cc.gatech.edu/data_files/classes/cs6390
  /slides/lisp.pdf
• http//web.syr.edu/aalarifi/Common20Lisp.pdf
• http//norvig.com/python-lisp.html