COM 1358 Assignment #6.
Due: Thursday, 1 June 2000

Submit this assignment by sending email to will@ccs.neu.edu with a subject
of "COM 1358 assignment 6".  Be careful:  Many email programs insert extra
line breaks or truncate long lines.  Either of these would corrupt your
self-reproducing program, so be sure to test your email software before
submitting this assignment.

The interpreter of Figure 3.16 can be loaded into an implementation
of R5RS Scheme as follows.

    % scheme
    > (begin (load "/course/com1358/pub/r5rs.scm")
             (load "/course/com1358/pub/define-datatype.scm")
             (load "/course/com1358/pub/sllgen.scm")
             (load "/course/com1358/pub/assignment6.scm"))

If you are using Chez Scheme, Larceny, or DrScheme, you can substitute
"chez.scm", "larceny.scm", or "drscheme.scm" for "r5rs.scm".  If you
are using DrScheme, you may also have to substitute
"define-datatype-drscheme.scm" for "define-datatype.scm".

1.  Time how long it takes to run the programs in

        /course/com1358/pub/EOPLsieve1.sch
        /course/com1358/pub/EOPLsieve2.sch

    Report these two timings, their units (e.g. CPU milliseconds), the
    machine on which you obtained them (e.g. archenar, a Sun Ultra 1
    running at 167 MHz), the Scheme system you are using (e.g. Chez Scheme),
    and the optimization level (e.g. the default optimizations).

2.  The two programs that you benchmarked in part 1 are identical except
    that EOPLsieve1.sch simulates call-by-name, while EOPLsieve2.sch
    simulates call-by-need.  Which was faster?  Why?

3.  Add read statements to assignment6.scm as specified in exercise
    3.9.1.  Turn in the modified grammar and the modified code for
    execute-statement.

4.  [If you did this for assignment #4, you do not need to do it again.]
    Write a complete Java application in a file named SelfReproducing.java
    that takes no inputs and writes its own source code to System.out.
    This program should not perform any i/o except for printing to System.out.
    Turn in the complete source code for SelfReproducing.java, preferably
    as an attachment to your email.

    If you do this correctly, the diff command below should produce a line
    of zeroes.

    % javac SelfReproducing.java
    % java SelfReproducing > temp
    % diff SelfReproducing.java temp | wc
       0       0       0