#
Introduction to Computing

Explorations in Language, Logic, and Machines

David
Evans

## Errata

- Exercise 2.14 - letterDigitHyphen not defined! (corrected 2009-12-29)
- Exercise 3.8 - the example is incorrect! It says, "For example, (xor true true) should evaluate to false and (xor (< 3 5) (= 8 8)) should evaluate to true.".
Actually,
`(xor (< 3 5) (= 8 8))` should evaluate to **false** since both of the inputs are true. (Thanks to Awab Osman) (5 July 2018)
- p. 100:
`list-increment 1 2` (corrected sometime in 2010)
- p. 130: (thanks to Anna Slagle) "The right output bit (r_0) is 1 when exactly one of the input bits is a
1: r_0 = (or (and (not A) B) (and A (not B))" (corrected sometime in
2010)
- p. 152
`n = 38` (thanks to Kristine Dell)
- p 166 "xists" (corrected 2009-12-29)
- Chapter 9 - the Charme interpreter code does not follow python
naming conventions
- Chapter 8 (p. 172) - the code for
`merge-indexes` has 3
extra closing parentheses at the end (thanks to Ezio Da Fonseca)
(corrected in book sources, 2013-10-13)
- p. 199 - Before
`(ask counter 'adjust! 5)` we need to
redefine counter: `(define counter
(make-adjustable-counter))`. (Thanks to Ezio Da Fonseca,
corrected in book sources, 2013-10-22)