Programming with LISP

1. CSE240 – Introduction to
Programming Languages
Lecture 16:
Programming with LISP
Javier Gonzalez-Sanchez
javiergs@asu.edu
javiergs.engineering.asu.edu
Office Hours: By appointment

2. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 2
Functional Paradigm

3. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 3
Semantic
Functional Paradigm
Key idea:
Focus on higher level of abstraction
(free from programming details)
Features:
Simpler semantic: no data types, and
a simpler syntax

4. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 4
Syntax
• Uniform representation of instructions and data using a single general
format– a list.
(functionId param1 param2 param3 ...)
• (+ 3 2 7 9) ; add 3+2+7+9 and return the result
21
• (* 4 2.3) ; multiply 4 by 2.3 and return the result
9.2
• (subseq "Hello, World" 2 9)
"llo, Wo"

5. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 5
Functional Programming
• Language: we will use LISP (LISt Processing).
• It uses an interpreter.
• Automatic management of memory.

6. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 6
You need an Interpreter
• LispWork Personal Edition –
http://www.lispworks.com/downloads/index.html
• Compile Lisp Online –
http://rextester.com/l/common_lisp_online_compiler
• Steel Bank Common Lisp –
http://www.sbcl.org/platform-table.html

7. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 7
Functional Programming
• A program is a set of lists and they are enclosed with parenthesis.
• We use lists to represent functions; in a function the first element of the list is
the id of the function and the rest are parameter(s)
• Whitespace separate function id and parameters
• Examples:
( print "Hello World" )
( + 2 2 )
( sqrt 2 )

8. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 8
Important Notice !

9. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 9
Everything is a List
• A function ID (symbol) is a series of characters other than whitespace, parentheses ( ), pound
( # ), quote ( ' ), double-quote ( " ), period ( . ), or back quote ( ` ).
• A function ID (symbol) may not take the form of numbers.
• It's very common for symbols to have hyphens ( - ) or asterisks ( * ) in them.
• There are NOT operators! only functions
• Symbols (function ID) are case-INSENSITIVE.

10. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 10
Atomic Expressions
• -3
• 2.43
• 123342303923412323411323234012923492341231230234923410239234412
• #C(3.2 2) ; the complex number 3.2 + 2i
• 2/3 ; the fraction 2/3. It is NOT divide 2 by 3
• -3.2e25 ; the number -3.2 x 10^25
• #g ; characters starts with #
• #{
• # ; the character ''
• #tab
• #newline
• #space
• #backspace
• #escape

11. Javier Gonzalez-Sanchez | CSE 240 | Fall 2017 | 11
Atomic Expressions
• "Hello, World!"
• "It's a glorious day."
• "He said "No Way!" and then he left."
• "I think I need a backslash here: Ah, that was better."
• t ; true
• nil ; false

12. CSE240 – Introduction to Programming Languages
Javier Gonzalez-Sanchez
javiergs@asu.edu
Fall 2017
Disclaimer. These slides can only be used as study material for the class CSE240 at ASU. They cannot be distributed or used for another purpose.