NAME<\/a> ______________________________________________________________________________<\/p>\n uplevel \u2212 Execute a script in a different stack frame<\/p>\n uplevel<\/b> ?level<\/i>? arg<\/i> ?arg …<\/i>? ______________________________________________________________________________<\/p>\n All of the arg<\/i> arguments are concatenated as if they had been passed to concat<\/b>; the result is then evaluated in the variable context indicated by level<\/i>. Uplevel<\/b> returns the result of that evaluation.<\/p>\n If level<\/i> is an integer then it gives a distance (up the procedure calling stack) to move before executing the command. If level<\/i> consists of #<\/b> followed by a number then the number gives an absolute level number. If level<\/i> is omitted then it defaults to 1<\/b>. Level<\/i> cannot be defaulted if the first command<\/i> argument starts with a digit or #<\/b>.<\/p>\n For example, suppose that procedure a<\/b> was invoked from top-level, and that it called b<\/b>, and that b<\/b> called c<\/b>. Suppose that c<\/b> invokes the uplevel<\/b> command. If level<\/i> is 1<\/b> or #2<\/b> or omitted, then the command will be executed in the variable context of b<\/b>. If level<\/i> is 2<\/b> or #1<\/b> then the command will be executed in the variable context of a<\/b>. If level<\/i> is 3<\/b> or #0<\/b> then the command will be executed at top-level (only global variables will be visible).<\/p>\n The uplevel<\/b> command causes the invoking procedure to disappear from the procedure calling stack while the command is being executed. In the above example, suppose c<\/b> invokes the command<\/p>\n uplevel<\/b> 1 {set x 43; d}<\/p>\n where d<\/b> is another Tcl procedure. The set<\/b> command will modify the variable x<\/b> in b<\/b>\u2019s context, and d<\/b> will execute at level 3, as if called from b<\/b>. If it in turn executes the command<\/p>\n uplevel<\/b> {set x 42}<\/p>\n then the set<\/b> command will modify the same variable x<\/b> in b<\/b>\u2019s context: the procedure c<\/b> does not appear to be on the call stack when d<\/b> is executing. The info level<\/b> command may be used to obtain the level of the current procedure.<\/p>\n Uplevel<\/b> makes it possible to implement new control constructs as Tcl procedures (for example, uplevel<\/b> could be used to implement the while<\/b> construct as a Tcl procedure).<\/p>\n The namespace eval<\/b> and apply<\/b> commands offer other ways (besides procedure calls) that the Tcl naming context can change. They add a call frame to the stack to represent the namespace context. This means each namespace eval<\/b> command counts as another call level for uplevel<\/b> and upvar<\/b> commands. For example, info level 1<\/b> will return a list describing a command that is either the outermost procedure call or the outermost namespace eval<\/b> command. Also, uplevel #0<\/b> evaluates a script at top-level in the outermost namespace (the global namespace).<\/p>\n As stated above, the uplevel<\/b> command is useful for creating new control constructs. This example shows how (without error handling) it can be used to create a do<\/b> command that is the counterpart of while<\/b> except for always performing the test after running the loop body:<\/p>\n proc do {body while condition} { apply(n), namespace(n), upvar(n)<\/p>\n context, level, namespace, stack frame, variable<\/p>\n uplevel \u2212 Execute a script in a different stack frame <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3783,1],"tags":[2635,2860],"class_list":["post-6240","post","type-post","status-publish","format-standard","hentry","category-n-comandos-tcl-tk","category-sin-categoria","tag-mann","tag-uplevel"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/6240","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/comments?post=6240"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/6240\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=6240"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=6240"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=6240"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
SYNOPSIS<\/a>
DESCRIPTION<\/a>
EXAMPLE<\/a>
SEE ALSO<\/a>
KEYWORDS<\/a> <\/p>\n
\nNAME <\/a> <\/h2>\n
SYNOPSIS <\/a> <\/h2>\n
DESCRIPTION <\/a> <\/h2>\n
EXAMPLE <\/a> <\/h2>\n
if {$while ne “while”} {
error “required word missing”
}
set conditionCmd [list expr $condition]
while {1} {
uplevel<\/b> 1 $body
if {![uplevel<\/b> 1 $conditionCmd]} {
break
}
}
}<\/p>\nSEE ALSO <\/a> <\/h2>\n
KEYWORDS <\/a> <\/h2>\n
\n","protected":false},"excerpt":{"rendered":"