I have not understood when components of a tacit definition may be nouns, and
when they must be verbs.
Writing J (instead of Scheme) to solve Exercise 4.2.3. of HTDP* I did this:
e4231 =: 62=2+4*]
e4232 =: 102=2*]^2
e4231
┌──┬─┬─────────────┐
│62│=│┌─┬─┬───────┐│
│ │ ││2│+│┌─┬─┬─┐││
│ │ ││ │ ││4│*│]│││
│ │ ││ │ │└─┴─┴─┘││
│ │ │└─┴─┴───────┘│
└──┴─┴─────────────┘
e4232
0
e4232 =: 102=2*]^2:
e4232
┌───┬─┬──────────────┐
│102│=│┌─┬─┬────────┐│
│ │ ││2│*│┌─┬─┬──┐││
│ │ ││ │ ││]│^│2:│││
│ │ ││ │ │└─┴─┴──┘││
│ │ │└─┴─┴────────┘│
└───┴─┴──────────────┘
So, I guessed correctly that verbalizing the exponent let e4232 be defined as a
verb, instead of a noun. What I cannot do is explain why that value, alone,
had to occur in verb form.
Which study material is recommended so that I may have a clear sense of how to
prevent intended verbs from being defined as nouns, and how to know when
constant values in definitions may be nouns, as opposed to constant verbs?
Tracy
* How to Design Programs: An Introduction to Computing and Programming
by Felleisen, Findler, Flatt, and Krishnamurthi
http://www.htdp.org/2003-09-26/Book/curriculum-Z-H-7.html#node_sec_4.2
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
