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I am.


Apr
3
accepted In Scheme, what is formally a program's state?
Apr
3
comment In Scheme, what is formally a program's state?
John, your definition of state agrees with this lecture of a course on Structure and Interpretation of Computer Programs.
Mar
29
comment In Scheme, what is formally a program's state?
Thanks for the link, Paul. I hoped there was an easier description of a state that "machine memory". By the way, it is not a complete definition, because you would need to also define what is stored in the memory and how. I will try to look through the article.
Mar
29
comment In Scheme, what is formally a program's state?
I have though of this, but could not convince myself that there is nothing more in a state. For example, if there is some external input-output. Could you give me some reference to more information on small-step semantics for Scheme, please? It is hard for me for now to translate operational semantics to such "program transformation" semantics, for example i do not see what would be a small step to reduce something like (quote x), or why this form is "irreducible".
Mar
28
comment In Scheme, what is formally a program's state?
I think i would be satisfied with any single answer out of infinitely many, preferably the shortest one, for any single "semantics". (I guess that without a semantics a Scheme program is just a sequence of Unicode symbols anyway.) If a Scheme program is not to be evaluated but to be "reduced", i would be interested to hear about it too, but from what i have read so far, it looks like after all a Scheme program describes a "computation" in some sense. As far as i know, a computation must be a sequence of states.
Mar
28
comment In Scheme, what is formally a program's state?
Thanks for the information and references, but i am looking for a one- or two-line definition if possible.
Mar
28
asked In Scheme, what is formally a program's state?
Mar
25
awarded  Notable Question
Feb
27
comment Is there an idiom for a loop that executes some block of instructions between iterations? (In Ruby in particular)
It seems that this is an inherent fault in all loop constructs that i know: for some reason the default exit point is always put just before the entry point, but i see no reason whatsoever for this to be a common scenario. In my opinion, most loops are "loops-and-a-half".
Feb
27
accepted Is there an idiom for a loop that executes some block of instructions between iterations? (In Ruby in particular)
Feb
27
comment Is there an idiom for a loop that executes some block of instructions between iterations? (In Ruby in particular)
Hm, it does not look like the output of ERB will be what i want. In fact, i would want to output blocks of HTML in a loop, joining them with other blocks, on so that the ERB or Haml template was easily readable.
Feb
26
comment Is there an idiom for a loop that executes some block of instructions between iterations? (In Ruby in particular)
Thanks for the Haskel example anyway.
Feb
26
comment Is there an idiom for a loop that executes some block of instructions between iterations? (In Ruby in particular)
Unfortunately, this solution will not look very clear inside a template language like ERB or Haml, at least i do not see how to make it clear.
Feb
26
comment Is there an idiom for a loop that executes some block of instructions between iterations? (In Ruby in particular)
Can you be more specific, please?
Feb
26
asked Is there an idiom for a loop that executes some block of instructions between iterations? (In Ruby in particular)
Aug
24
comment Is Liskov Substitution Principle incompatible with Introspection or Duck Typing?
@Geek, q(x) means a property with free variable x, like, for example, "x is red".
Aug
11
awarded  Supporter
Aug
11
comment How can software be protected from piracy?
I would put this answer shorter: "Open source".
Aug
9
comment SQL: empty string vs NULL value
@Ramhound, i agree that the empty string is a value, and that NULL vaguely means "there is no value". I just explained my interpretation of "no value". In my opinion, it is not the same as "the person has not opened any email account". It is rather "no email address recorded for that person".
Aug
8
comment SQL: empty string vs NULL value
I think NULL does not mean that there is no email address, i think it means that the email address is currently not known, not known to exist, or is impossible to fill in for other reasons. Fortunately, the is probably no situation where one would want to keep in a database the information about people who truly do not have and do not plan to have any email address, otherwise a separate boolean field would probably be necessary.