CVS commit: src/usr.bin/make/unit-tests

["Roland Illig" <rillig%netbsd.org@localhost>]

Module Name:    src
Committed By:   rillig
Date:           Sat Oct  3 17:30:54 UTC 2020

Modified Files:
        src/usr.bin/make/unit-tests: Makefile
Added Files:
        src/usr.bin/make/unit-tests: hanoi-include.exp hanoi-include.mk

Log Message:
make(1): add test demonstrating the Towers of Hanoi puzzle

It's not the primary task of make to handle procedure calls with
parameters, combined with lexical scoping, therefore the code does not
look as straight-forward or clean as in other programming languages.  It
feels more like squeezing a programming problem from the imperative
world into the world of declarative dependencies.

A more idiomatic way of implementing this puzzle should be as a
dependency graph since that's both the natural structure of the puzzle
and the primary domain of make.  Something like having a main target
"hanoi-5" that depends on intermediate targets of the form
"move-1.2.3.4.5-_._._._._-_._._._._", each representing a single
configuration of the stacks.  These targets could be generated
dynamically.  A benefit of this implementation would be that the puzzle
could be resumed from an arbitrary configuration, just just from the
initial configuration.


To generate a diff of this commit:
cvs rdiff -u -r1.158 -r1.159 src/usr.bin/make/unit-tests/Makefile
cvs rdiff -u -r0 -r1.1 src/usr.bin/make/unit-tests/hanoi-include.exp \
    src/usr.bin/make/unit-tests/hanoi-include.mk

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.