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Transcript lisp_47542238 

Lisp
"List Processing"
Lisp history
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John McCarthy developed the basics behind Lisp during
the 1956 Dartmouth Summer Research Project on
Artificial Intelligence
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He intended it as an algebraic LISt Processing (hence
the name) language for artificial intelligence work
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He showed how, given a handful of simple operators and
anotation for functions, you can build a whole
programming language.
Design Goals
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Formalism for developing a theory of computation
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Programming language for numerical and logical
problems
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Symbolic manipulation of expressions and sentences
Characteristics
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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
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Interest in symbolic computation influenced design
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Use of simple machine model
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Attention to theoretical considerations Recursive
function theory, Lambda calculus
Distinctive Characteristics
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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.
Relative Speeds of 5 language
Description of Lisp
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LISP is usually used as an interpreted
language.
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The interpreter runs what is known as a
read- evaluates-print loop.
Description of Lisp
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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).
Defining Lisp Function
Use defun to define your own functions in LISP.
(defun <name> <parameter-list> <body>)
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Example:
>(defun square (x) (* x x))
SQUARE
>(square 2)
4
Example Code
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reverse : Format: (reverse <list>)
Reverse returns a list that contains all the
elements of <list> in reversed order.
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Example:
> (reverse '(picard riker worf crusher))
(CRUSHER WORF RIKER PICARD)
> (reverse (reverse '(picard riker worf crusher)))
(PICARD RIKER WORF CRUSHER)
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Resources
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http://faqs.org/faqs/lisp-faq/part2/section-13.html
http://www.cc.gatech.edu/data_files/classes/cs6390/slides/lisp.pdf
http://web.syr.edu/~aalarifi/Common%20Lisp.pdf
http://norvig.com/python-lisp.html