diff options
Diffstat (limited to 'doc/namespace.n')
| -rw-r--r-- | doc/namespace.n | 176 |
1 files changed, 94 insertions, 82 deletions
diff --git a/doc/namespace.n b/doc/namespace.n index dfd0467..1f4e85f 100644 --- a/doc/namespace.n +++ b/doc/namespace.n @@ -7,10 +7,8 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: namespace.n,v 1.35 2008/10/17 10:22:25 dkf Exp $ -'\" -.so man.macros .TH namespace n 8.5 Tcl "Tcl Built-In Commands" +.so man.macros .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME @@ -119,7 +117,7 @@ they are automatically created. Returns \fB1\fR if \fInamespace\fR is a valid namespace in the current context, returns \fB0\fR otherwise. .TP -\fBnamespace export \fR?\-\fBclear\fR? ?\fIpattern pattern ...\fR? +\fBnamespace export \fR?\fB\-clear\fR? ?\fIpattern pattern ...\fR? . Specifies which commands are exported from a namespace. The exported commands are those that can be later imported @@ -175,6 +173,8 @@ namespaces. The commands in the returned list are in the format of simple names, with no namespace qualifiers at all. This format is suitable for composition with \fBnamespace forget\fR (see \fBEXAMPLES\fR below). +.RS +.PP When \fIpattern\fR arguments are present, each \fIpattern\fR is a qualified name like \fBfoo::x\fR or \fBa::p*\fR. @@ -182,6 +182,11 @@ That is, it includes the name of an exporting namespace and may have glob-style special characters in the command name at the end of the qualified name. Glob characters may not appear in a namespace name. +When the namespace name is not fully qualified (i.e., does not start +with a namespace separator) it is resolved as a namespace name in the +way described in the \fBNAME RESOLUTION\fR section; it is an error if +no namespace with that name can be found. +.PP All the commands that match a \fIpattern\fR string and which are currently exported from their namespace are added to the current namespace. @@ -190,7 +195,7 @@ that points to the exported command in its original namespace; when the new imported command is called, it invokes the exported command. This command normally returns an error if an imported command conflicts with an existing command. -However, if the \-\fBforce\fR option is given, +However, if the \fB\-force\fR option is given, imported commands will silently replace existing commands. The \fBnamespace import\fR command has snapshot semantics: that is, only requested commands that are currently defined @@ -199,6 +204,7 @@ In other words, you can import only the commands that are in a namespace at the time when the \fBnamespace import\fR command is executed. If another command is defined and exported in this namespace later on, it will not be imported. +.RE .TP \fBnamespace inscope\fR \fInamespace\fR \fIscript\fR ?\fIarg ...\fR? . @@ -281,7 +287,7 @@ This command is the complement of the \fBnamespace qualifiers\fR command. It does not check whether the namespace names are, in fact, the names of currently defined namespaces. .TP -\fBnamespace upvar\fR \fInamespace\fR ?\fIotherVar myVar \fR... +\fBnamespace upvar\fR \fInamespace\fR ?\fIotherVar myVar \fR...? . This command arranges for zero or more local variables in the current procedure to refer to variables in \fInamespace\fR. The namespace name is @@ -296,7 +302,8 @@ used for qualified namespace or variable names. . Sets or returns the unknown command handler for the current namespace. The handler is invoked when a command called from within the namespace -cannot be found (in either the current namespace or the global namespace). +cannot be found in the current namespace, the namespace's path nor in +the global namespace. The \fIscript\fR argument, if given, should be a well formed list representing a command name and optional arguments. When the handler is invoked, the full invocation line will be appended to the @@ -304,7 +311,7 @@ script and the result evaluated in the context of the namespace. The default handler for all namespaces is \fB::unknown\fR. If no argument is given, it returns the handler for the current namespace. .TP -\fBnamespace which\fR ?\-\fBcommand\fR? ?\-\fBvariable\fR? \fIname\fR +\fBnamespace which\fR ?\fB\-command\fR? ?\fB\-variable\fR? \fIname\fR . Looks up \fIname\fR as either a command or variable and returns its fully-qualified name. @@ -332,13 +339,13 @@ For example, .PP .CS \fBnamespace eval\fR Counter { - \fBnamespace export\fR bump - variable num 0 + \fBnamespace export\fR bump + variable num 0 - proc bump {} { - variable num - incr num - } + proc bump {} { + variable num + incr num + } } .CE .PP @@ -364,19 +371,19 @@ as the namespace definition shown above: .PP .CS \fBnamespace eval\fR Counter { - variable num 0 - proc bump {} { - variable num - return [incr num] - } + variable num 0 + proc bump {} { + variable num + return [incr num] + } } \fBnamespace eval\fR Counter { - proc test {args} { - return $args - } + proc test {args} { + return $args + } } \fBnamespace eval\fR Counter { - rename test "" + rename test "" } .CE .PP @@ -469,24 +476,25 @@ you mean. However, if the name does not start with a \fB::\fR (i.e., is \fIrelative\fR), Tcl follows basic rules for looking it up: -Variable names are always resolved -by looking first in the current namespace, -and then in the global namespace. -Command names are also always resolved by looking in the current -namespace first. If not found there, they are searched for in every -namespace on the current namespace's command path (which is empty by -default). If not found there, command names are looked up in the -global namespace (or, failing that, are processed by the \fBunknown\fR -command.) -Namespace names, on the other hand, are always resolved -by looking in only the current namespace. +.IP \(bu +\fBVariable names\fR are always resolved by looking first in the current +namespace, and then in the global namespace. +.IP \(bu +\fBCommand names\fR are always resolved by looking in the current namespace +first. If not found there, they are searched for in every namespace on the +current namespace's command path (which is empty by default). If not found +there, command names are looked up in the global namespace (or, failing that, +are processed by the appropriate \fBnamespace unknown\fR handler.) +.IP \(bu +\fBNamespace names\fR are always resolved by looking in only the current +namespace. .PP In the following example, .PP .CS set traceLevel 0 \fBnamespace eval\fR Debug { - printTrace $traceLevel + printTrace $traceLevel } .CE .PP @@ -500,11 +508,11 @@ To make this point absolutely clear, consider the following example: .CS set traceLevel 0 \fBnamespace eval\fR Foo { - variable traceLevel 3 + variable traceLevel 3 - \fBnamespace eval\fR Debug { - printTrace $traceLevel - } + \fBnamespace eval\fR Debug { + printTrace $traceLevel + } } .CE .PP @@ -641,27 +649,27 @@ You can export commands from a namespace like this: .PP .CS \fBnamespace eval\fR Counter { - \fBnamespace export\fR bump reset - variable Num 0 - variable Max 100 + \fBnamespace export\fR bump reset + variable Num 0 + variable Max 100 - proc bump {{by 1}} { - variable Num - incr Num $by - Check - return $Num - } - proc reset {} { - variable Num - set Num 0 - } - proc Check {} { - variable Num - variable Max - if {$Num > $Max} { - error "too high!" - } - } + proc bump {{by 1}} { + variable Num + incr Num $by + Check + return $Num + } + proc reset {} { + variable Num + set Num 0 + } + proc Check {} { + variable Num + variable Max + if {$Num > $Max} { + error "too high!" + } + } } .CE .PP @@ -683,22 +691,23 @@ may be imported by other namespaces. If a \fBnamespace import\fR command specifies a command that is not exported, the command is not imported. .SH "SCOPED SCRIPTS" +.PP The \fBnamespace code\fR command is the means by which a script may be packaged for evaluation in a namespace other than the one in which it was created. It is used most often to create event handlers, Tk bindings, and traces for evaluation in the global context. For instance, the following -code indicates how to direct a variable trace callback into the current +code indicates how to direct a variable \fBtrace\fR callback into the current namespace: .PP .CS \fBnamespace eval\fR a { - variable b - proc theTraceCallback { n1 n2 op } { - upvar 1 $n1 var - puts "the value of $n1 has changed to $var" - return - } - trace variable b w [\fBnamespace code\fR theTraceCallback] + variable b + proc theTraceCallback { n1 n2 op } { + upvar 1 $n1 var + puts "the value of $n1 has changed to $var" + return + } + trace add variable b write [\fBnamespace code\fR theTraceCallback] } set a::b c .CE @@ -769,7 +778,10 @@ When non-empty, this option supplies a dictionary that provides a mapping from subcommand names to a list of prefix words to substitute in place of the ensemble command and subcommand words (in a manner similar to an alias created with \fBinterp alias\fR; the words are not -reparsed after substitution). When this option is empty, the mapping +reparsed after substitution); if the first word of any target is not +fully qualified when set, it is assumed to be relative to the +\fIcurrent\fR namespace and changed to be exactly that (that is, it is +always fully qualified when read). When this option is empty, the mapping will be from the local name of the subcommand to its fully-qualified name. Note that when this option is non-empty and the \fB\-subcommands\fR option is empty, the ensemble subcommand names @@ -884,12 +896,12 @@ Create a namespace containing a variable and an exported command: .PP .CS \fBnamespace eval\fR foo { - variable bar 0 - proc grill {} { - variable bar - puts "called [incr bar] times" - } - \fBnamespace export\fR grill + variable bar 0 + proc grill {} { + variable bar + puts "called [incr bar] times" + } + \fBnamespace export\fR grill } .CE .PP @@ -901,8 +913,8 @@ Call the command defined in the previous example in various ways. # Use the command resolution path to find the name \fBnamespace eval\fR boo { - \fBnamespace path\fR ::foo - grill + \fBnamespace path\fR ::foo + grill } # Import into current namespace, then call local alias @@ -912,8 +924,8 @@ grill # Create two ensembles, one with the default name and one with a # specified name. Then call through the ensembles. \fBnamespace eval\fR foo { - \fBnamespace ensemble\fR create - \fBnamespace ensemble\fR create -command ::foobar + \fBnamespace ensemble\fR create + \fBnamespace ensemble\fR create -command ::foobar } foo grill foobar grill @@ -938,10 +950,10 @@ and second arguments. .PP .CS \fBnamespace eval\fR do { - \fBnamespace export\fR * - \fBnamespace ensemble\fR create -parameters x - proc plus {x y} {expr { $x + $y }} - proc minus {x y} {expr { $x - $y }} + \fBnamespace export\fR * + \fBnamespace ensemble\fR create -parameters x + proc plus {x y} {expr { $x + $y }} + proc minus {x y} {expr { $x - $y }} } # In use, the ensemble works like this: |