Beefy Boxes and Bandwidth Generously Provided by pair Networks
XP is just a number
 
PerlMonks  

Re: Re: Lexical scoping like a fox

by broquaint (Abbot)
on Dec 03, 2002 at 17:28 UTC ( #217287=note: print w/ replies, xml ) Need Help??


in reply to Re: Lexical scoping like a fox
in thread Lexical scoping like a fox

From this description and the examples it might not be clear that $foo is in scope from its declaration to the end of the enclosing block or file
Good point, but I do mention file-scoped lexicals later on in the tutorial and I don't like forward-referencing in learning material. Will see if I can clear it up somehow though.
I think that the point Elian makes about destruction is still valid. The lifetime of an item is a separate issue to its scope (lexical or otherwise).
This is true, but I didn't think it was necessary to go into the details of reference counting for something as simple as a lexical scoping tutorial. I was trying to keep it as straight forward as possible and adding memory management into the fray would almost certainly confuse the reader. Perhaps I should put a reference to Matts' Proxy Objects article as further reading.
Another way you can demonstrate this nicely is with a BEGIN block.
Marvellous! That illustrates the compile time vs runtime concept beautifully.
Not entirely sure that this is quite clear enough - especially the phrase "length of a given lexical scope".
I do labour the meaning of the 'length' of a lexical scope shortly after, and I can't think of another way of clearing stating how a dynamic scope is defined (perhaps a more judicious use of commenting the code would do the trick) so it'll have to do for now :)
Might be worth mentioning the historical context
Indeed, think I'll stick a line in there to elaborate on why local has such an ambiguous definition.
This is, of course, equally true of dynamic scoped variables
True, but I didn't want to mention the fact that localised dynamic variables are in fact *new* variables because I reckon it would add yet another layer of complexity that the tutorial could do without.

Thanks again for the input, it is most insightful indeed! I think the whole tutorial will need get another revision and then posted to Tutorials.
HTH

_________
broquaint


Comment on Re: Re: Lexical scoping like a fox

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://217287]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others cooling their heels in the Monastery: (3)
As of 2014-07-24 02:58 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    My favorite superfluous repetitious redundant duplicative phrase is:









    Results (156 votes), past polls