Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation
 
PerlMonks  

Re^6: What can we assume in a BEGIN block ?

by leriksen (Curate)
on Oct 05, 2004 at 00:05 UTC ( #396438=note: print w/ replies, xml ) Need Help??


in reply to •Re^5: What can we assume in a BEGIN block ?
in thread What can we assume in a BEGIN block ?

Yep, I think my main problem was understanding what 'parse' meant.

Discussion below uses this code

our $initialised = 0; BEGIN { _initialise(); $initialised = 1; }

Initially (when I didnt understand the problem) I thought the bare (not in a BEGIN) our $initialised = 0; meant 'found a scalar declaration, allocate memory, create an entry in the symbol table that references that location,and put a 0 in that memory location. Now parse and run the BEGIN block, which will result in $initialised having a 1 in it'.

Now I (think/know) it means 'found a scalar declaration, allocate memory, create an entry in the symbol table that references that location,and generate some opcodes that will result in a 0 being put in that location at runtime.Now parse and run the BEGIN block, which will result in $initialised having a 1 in it, which will get clobbered back to 0 by the opcodes at runtime'

Thanx merlyn for taking the time to break this down for me. I hope I have it straight now.

use brain;


Comment on Re^6: What can we assume in a BEGIN block ?
Select or Download Code

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://396438]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others browsing the Monastery: (5)
As of 2015-07-08 02:42 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









    Results (93 votes), past polls