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atomic_scope [2007/02/15 03:53] (current)
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 +======Atomic Scopes======
 +
 +=====What is an atomic scope?​======
 +An //atomic scope// is the period of time during which local variables live.
 +At the beginning of an //atomic scope// there are no local variables, and 
 +at the end of that //atomic scope//, all local variables are destroyed.
 +Thus, the //atomic scope// defines the availability and lifetime of a local
 +variable.
 +
 +When the client starts up, it creates a global //atomic scope// that lives
 +for the entire lifetime of the client. ​ Thus it is always possible to create
 +local variables, even from the input prompt.
 +
 +From time to time (see the list below), the client creates new atomic scopes.
 +When a new atomic scope is created, any local variables that were visible in
 +the previous atomic scope are hidden and can no longer be accessed! ​ The
 +client arranges for this by using a stack. ​ Each atomic scope can see only
 +those local variables on its position in the stack.
 +
 +Eventually an atomic scope ends, and then its local variables are destroyed.
 +They cannot be recovered once the atomic scope ends.  Because the scopes are 
 +stored as a stack, atomic scopes are destroyed in a strict Last-In-First-Out ​
 +order.
 +
 +======The list of atomic scopes======
 +  * Commands executed by [[defer]]
 +  * Files loaded by the [[pf loader]]
 +  * [[exec]] -line, -error, or -end callbacks
 +  * Commands executed by [[wait]] -cmd
 +  * User-created key[[bind]]ing callbacks
 +  * Commands executed by [[queue]]
 +  * Commands executed by [[timer]]
 +  * User-created [[set]] callbacks
 +  * [[Who]] -line or -end callbacks
 +  * [[Ison]] -oncmd, -offcmd, or -end callbacks
 +  * [[Userhost]] -cmd callbacks
 +  * [[ON]] callback bodies
 +  * Each time an [[alias]] is executed
 +
 +======Sharing local variables:​======
 +[future expansion]
 +
 +======History:​======
 +Local variables first appeared in EPIC4pre0.009
 +
  
atomic_scope.txt ยท Last modified: 2007/02/15 03:53 (external edit)