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quoting_hell [2007/07/10 21:03] (current)
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 +======Quoting hell======
 +=====What is quoting hell?======
 +//Quoting hell// is a catch-all term used to describe the edge places in 
 +ircII's quirky syntax where it is not at all obvious just how you're 
 +supposed to make something work.  
 +Of course you know by now that in the ircII language, data and code are 
 +fully interchangable.  When you want to run a piece of code later, the 
 +usual way to do this is to pass the code as a string argument to another
 +command that queues it up.
 +Because arguments to functions are subject to $-expansion and \\-dequoting,
 +sometimes you don't wan the $'s to be expanded at the time you queue up
 +the code (now), but rather when the code is executed (later).  Usually 
 +you can do this by doubling up $'s and \'ing any characters that have special
 +meanings, such as semicolons.
 +This is more of an art than a science, and the unpleasant situation of trying
 +to figure out just how many $'s you need to use to get that variable to expand
 +at just the right time is colloquially known as [[quoting hell]].
 +Let's say you want to output the time.  It is the $Z expando.
 + echo $Z
 +Let's say you want to output the time in 2 minutes:
 + timer 120 echo $Z
 +Oops!  That doesn't work, because the language doesn't know that "echo $Z"
 +is code, and it expands all $'s now.  You can double up the $ to prevent
 +the expansion from happening until later
 + timer 120 echo $$Z
 +Let's say you want to output the time in 2 minutes, but not if the client 
 +is doing something like a [[wait]] or a [[redirect]].
 + timer 120 defer echo $$Z
 +Oops!  That doesn't work, because $Z would be expanded at the time that the
 +[[defer]] is run, which might be much earlier than the echo.  You can double
 +up the $'s again to prevent the expansion at defer-time:
 + timer 120 echo $$$$Z
 +This is just a simple example of how crazy it can get.  This is //by no means//
 +the most obtuse example I could come up with.
 +=====More coming later:=====
 +This document is very much a work-in-progress
quoting_hell.txt ยท Last modified: 2007/07/10 21:03 (external edit)