Course Library Code Examples

This page gives access to code examples in the course library.

You can use the table of contents (on the web) to jump directly to the kind of example you are looking for.

If you click on a Scheme file name and your browser tries to download a plugin (e.g., for a Lotus Screen Cam Movie), then you need to change your browser's rules for associating file suffixes with viewers. One way to do this on Windows (95/98) is to go into the Windows Explorer, and click on "View" then "Folder Options", then click on the "File Types" tab, and then enter a new file type for .scm files.

Little Schemer, Chapter 2
Little Schemer, Chapter 3
Little Schemer, Chapter 4
Scheme Background
EOPL 2e Chapter 1
EOPL 2e Chapter 2
EOPL 2e Chapter 3
EOPL 2e Chapter 4
EOPL 2e Chapter 5
EOPL 2e Chapter 6

The Little Schemer, Chapter 2

Recursion over flat lists, without conditionals

list-copy-mod.scm, list-copy is a prototype for these kinds of procedures, although it doesn't seem to do much.

list-length-mod.scm (list-length)

add1-to-each-mod.scm (add1-to-each)

make-all-positive-mod.scm (make-all-positive)

mapcdr-mod.scm (mapcdr)

list-map-mod.scm (list-map)

The Little Schemer, Chapter 3

Recursion over flat lists, with conditionals

delete-even-mod.scm (delete-even)

The Little Schemer, Chapter 4

Recursion over the natural numbers

nat-leq-mod.scm (nat-leq)

nth-element-mod.scm (nth-element)

unary-notation-mod.scm (unary-notation)

expt-maker-mod.scm (expt-maker)

Scheme Background

Scheme Data Types

Write Scheme code to:

Construct and lists and improper lists
Use of quote, cons, and list primitives (and when to use each)
Extract parts of lists and improper lists

yodaize-mod.scm

whos-on-first-mod.scm

lambda*.scm, for example lambda-1-exp.scm

Understand:

Dot notation

dot-notation-mod.scm (dot-notation)

How to read and write our type notation (../typedscm/typedscm/typedscm.html)

In most files have type annotations (try the Unix command: grep deftype *.scm)

Scheme Expressions

Write Scheme code using expressions, statements, and definitions.

Make decisions using if expressions
Make declarations using define

nth-element-mod.scm (nth-element), among many other examples in lib.

Understand:

Differences between expressions, statements, and declarations.

Scheme Procedures

Use of map

matrix-ops.scm

sym-exp-mod.scm (parse-s-list)

remove-sym-exp-with-map.scm (remove-s-list)

Uses of curried procedures

grav-force-example.scm

expt-maker-mod.scm (expt-maker)

../typedscm/testing.scm (testing:eval-print-maker, testing:regression-test-maker-maker, ...)

../typedscm/tc-type-helpers.scm (tc:axiom-helper, tc:rule-helper, etc.)

vector-generator-mod.scm (see vector-generator-mod.tst and vector-map-mod.scm for how it's used)

Write variable arity procedures

sum-mod.scm (sum)

product-mod.scm (product)

atomic-tree.scm (tree)

set-ops-as-vector.scm (set-of, set-union*)

Syntactic Abstraction in Scheme

How to desugar expressions in Scheme (let, and, or, cond, case)

Be able to use let, letrec, and, or, cond, case in Scheme programs. There are lots of examples of this. You can grep for the appropriate keyword to find examples in the library files. The following are some simple examples.

examples of "and" and "or"

nat-leq-mod.scm (nat-leq)

set-ops-as-vector.scm (set-member?, set-subset?, set-equal?)

all-mod.scm (all)

some-mod.scm (some)

../typedscm/tc-type-helpers.scm (tc:rule-or-helper, tc:sequence)

examples of "let", "let*", "letrec", and "cond", e.g.,

whos-on-first-mod.scm

../typedscm/tc-type-helpers.scm (tc:sequence, ...)

EOPL Chapter 1

Inductive Specifications and Grammars (1.1)

BNF notation

lambda*.scm, for example lambda-1-exp.scm

The document defining our type notation, which uses BNF.

../typedscm/tc-output-type-expr.scm

Deriving Recursive Programs from Grammars (1.2)

How a grammar relates to the outline of a recursive procedure (1.2.1)

See also Gary T. Leavens, `` Following the Grammar,'' Department of Computer Science, Iowa State University, TR #05-02a, February 2005, revised January 2006.

Write recursive programs over flat lists (1.2.2)

sum-mod.scm (sum-of-list)

product-mod.scm (product-of-list)

../typedscm/tc-util.scm (tc:last-item, tc:some, tc:member?, tc:filter, tc:find-duplicates, ...)

../typedscm/chez/tc-ignore-types-at-runtime.scm (list-of)

Write recursive programs over other grammars (1.2.2)

select-outerwear-mod.scm (select-outerwear), which is an example using the temperature grammar (only alternatives, no recursion).

iseq-map-mod.scm (iseq-map), which is an example using the infinite sequence grammar (only recursion, no alternatives).

valid-number-mod.scm (valid-number), which is an example using the phone number grammar (multiple nonterminals, no recursion).

double-size-mod.scm (double-size) which is an example using the window-layout grammar.

negate-bexp-mod.scm (negate-bexp), which is an example using the boolean expression grammar.

targets-mod.scm (targets), which is an example using the statement-expression grammar.

remove-named-mod.scm (remove-named), which is an example using the SXML grammar (an abstract syntax for XML).

lambda-1-exp-examples.scm

lambda-1-quote-exp-examples.scm

lambda-if-exp-examples.scm

../typedscm/tc-output-type-expr.scm

../typedscm/tc-type-translate.scm (tc:type-vars, tc:output-type-vars, tc:nest-args, tc:type-unnest-args, tc:substq-all-output)

Write recursive programs over symbol-expression and lists of symbol-expressions (s-lists, pp. 19-22)

count-sym-exp-mod.scm

subst-mod.scm

num-of-mod.scm

remove-sym-exp-mod.scm

try these using sym-exp-cooked.scm, also instead of sym-exp-mod.scm

Tail Recursion (1.2.3)

Understand the difference between full recursion and tail recursion.

Examples of full recursion are found in the section above on deriving recursive programs from grammars. Compare the code for the fully recursive product-mod.scm with the tail recursive code in product-tail-recursive.scm. Note the pending computations surrounding the recursive calls in the fully-recursive version.