Re: Scott and George's Teaching Thread

On Aug 27, 4:34 pm, Scott <ToaTe...@xxxxxxxxx> wrote:
A definition is like a macro,

No.
Definition is a technical term.
The definition of "definition" is something deep and philosophical.
Lots of things get to have definitions. But we are going to
concentrate
on the technical use, on definitions INSIDE the theory. Other things
will have definitions in other places, like the natural-language
dictionary.

I was using macro in its informal computer science sense.
Macros have definitions but they are string-theoretical, NOT set-
theoretical.
You will see some set-theoretical definitions.

its just a syntactical re-arrangement of
symbols whose overall meaning does not change.

Macros have absolutely nothing to do with meaning;
the meaning of any argument to a macro is a very local thing,
and not something anybody needs to worry about.
Macros are not part of THIS course. I used the term because
I thought you might've seen it in a programming context.

So are &, |, ~, ->, and
<-> macros for predicates of FOL;

No.
All of those are from ZEROth-order logic.

ie, & is a macro for AND(t1,t2),

No; if macros were going to be involved; it would be the other way
around.
& is the primitive.
If you know about compilation then you know that there are higher-
and lower-level languages. We are viewing set theory as assembly-
language here.
Things like & and ~ are almost like machine-code.

etc.?

The notation "U c V =df Ax[xeU -> xeV]" is a notation used strictly
for readability, which means everywhere I see "UcV" I should replace
with "Ax[xeU -> xeV]";

Well, yes, in the sense that that's what it means,
but also simultaneously no, the point being that we are trying to
IMPROVE
readability, so it's easier if YOU think about it as a subset, than
translating
back down into assembly language.

eg, UcVcW is equivalent to Ax[xeU -> xeV -> > xeW]. Correct?

More irrelevant than correct; conditional is not associative, so
both of these ARE AMBIGUOUS; you should be MORE worried about
NEVER saying EITHER of them THAN you are about whether they mean the
same as each other.



.

Relevant Pages

  • Re: The War On HLA
    ... If you're assuming that macros' only purpose is for "in-line" functions, ... languages demonstrate the ability of using macros to extend the language. ... I would ask why you're using Delphi in the first place. ... programming language (i.e., you can assign them to variables, ...
    (alt.lang.asm)
  • Re: macro for shorter array syntax
    ... How is OCaml on adding readmacros, which Lisp can do easily. ... I would not ask that of a parsed language. ... We're confident that using macros is useful to us, ... debate has legitimate points on both sides. ...
    (comp.lang.lisp)
  • Re: LSE64 in standard Forth
    ... The cost of an additional add verses the cost of: ... language and the benefits and pitfalls of that language. ... LSE64 forces a lot more naming of things than Standard Forth, a thing I consider positive, but some in the group have criticized. ... The problem I have with macros is one well known in the C community: while a macro names a concept, it does not automatically provide a clean interface. ...
    (comp.lang.forth)
  • Re: Hey, what is all this off topic posting?
    ... >>> that's all you're using macros for, I can see why you don't much like ASM. ... > PL/I language constructs though. ... >> write the macros using some arcane assembler to do that on a new ...
    (sci.electronics.design)
  • Re: Python syntax in Lisp and Scheme
    ... >>expressive power because you believe it will be misused. ... people programming languages, both on the job and as a University ... that, Macros are just one. ... number of lines of code per year regardless of the language they write ...
    (comp.lang.lisp)
Quantcast