Talk:User defined pipe and redirection operators: Difference between revisions
Talk:User defined pipe and redirection operators (view source)
Revision as of 11:56, 4 June 2017
, 6 years agoSuggest changing the task to less language specific
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<lang tcl>pipeline cat bigfile.txt | grep "foo" | sort | head 5 | >> /dev/tty</lang>
Except with some minor changes (I used a real file and searched for something that I knew was there on about 1% of lines). –[[User:Dkf|Donal Fellows]] 10:56, 20 September 2011 (UTC)
I have to agree, so I 'reduced task description..." by removing the wikipedia cut/paste of "[[wp:Pipeline_(Unix)|Pipeline_(Unix)]]" as it didn't seem to add much value.
I'm still keen to see a degree of parallelism in the piping in the test case eg `cmd1;cmd2...` But strictly speaking this isn't an pipe or a redirection operator! Maybe it is worth putting conjunctions of pipes in another task...
[[User:NevilleDNZ|NevilleDNZ]] 12:53, 20 September 2011 (UTC)
:This comment reminds me of: http://jlouisramblings.blogspot.com/2011/07/erlangs-parallelism-is-not-parallelism.html -- or, from my point of view: we talk about "concurrency" and "parallelism" as if they were simple things when in fact they can represent a range of concepts, many of which are only loosely related to each other. Meanwhile, depending on the application, some of those concepts can be undesirable even though others are desirable. All of which can matter when dealing with issues of scope and practicality. --[[User:Rdm|Rdm]] 17:20, 21 September 2011 (UTC)
== Simplify description ==
Maybe the task description should simply read:
Create "user defined" the equivalents of the Unix shell "<", "|", ">", "<<", ">>" and $(cmd) operators and demonstate their operation.
Languages that do not support user defined operators should be omitted.
[[User:Markhobley|Markhobley]] 22:51, 9 February 2013 (UTC)
: That's not enough -- equivalence is contextual. Here, I can easily identify three different forms of equivalence, each of which allows a variety of variations even without considering optional combinations with the others.
:: Syntactic equivalence (ordering of the components)
:: Functional equivalence (results after execution)
:: Implementation equivalence (for example: similar buffer size and structure, use of fork(), ...)
: One problem, here, is that the interpretation favored on this site (functional equivalence) is trivial in the context of most programming languages - most of these operators wind up being "put a result somewhere". So, to avoid the trivialness of this task we might be inclined to favor an implementation equivalence (perhaps, including: buffer sizes less than multiple gigabytes in size, which in turn means buffers are required in the implementation), but where do you draw the line? For example, is it important to implement a process scheduler as a part of this task? [probably not, but what about the many other dozens of facets of how I have used these unix mechanisms?]. --[[User:Rdm|Rdm]] 03:33, 10 February 2013 (UTC)
:: I think just go for the trivial context for the purpose of this task, ie "put a result somewhere" is fine. For more complicated scenarios create a new task, eg "User defined pipe and redirection operators/With buffering", or "User defined pipe and redirection operators/With scheduler".
[[User:Markhobley|Markhobley]] 07:24, 10 February 2013 (UTC)
== Different grep ? ==
Perhaps the task details should be less "Algol oriented". The "Algol pioneers" count could be replaced by something more generic - "compiler" maybe? --[[User:Tigerofdarkness|Tigerofdarkness]] ([[User talk:Tigerofdarkness|talk]]) 11:55, 4 June 2017 (UTC)
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