diff options
Diffstat (limited to 'doc/next.n')
| -rw-r--r-- | doc/next.n | 31 |
1 files changed, 21 insertions, 10 deletions
@@ -4,17 +4,18 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -.so man.macros .TH next n 0.1 TclOO "TclOO Commands" +.so man.macros .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME -next \- invoke superclass method implementations +next, nextto \- invoke superclass method implementations .SH SYNOPSIS .nf package require TclOO \fBnext\fR ?\fIarg ...\fR? +\fBnextto\fI class\fR ?\fIarg ...\fR? .fi .BE @@ -30,6 +31,13 @@ of the next method in the method chain; if there are no further methods in the method chain, the result of \fBnext\fR will be an error. The arguments, \fIarg\fR, to \fBnext\fR are the arguments to pass to the next method in the chain. +.PP +The \fBnextto\fR command is the same as the \fBnext\fR command, except that it +takes an additional \fIclass\fR argument that identifies a class whose +implementation of the current method chain (see \fBinfo object\fR \fBcall\fR) should +be used; the method implementation selected will be the one provided by the +given class, and it must refer to an existing non-filter invocation that lies +further along the chain than the current implementation. .SH "THE METHOD CHAIN" .PP When a method of an object is invoked, things happen in several stages: @@ -54,14 +62,14 @@ The method chain is cached for future use. When constructing the method chain, method implementations are searched for in the following order: .IP [1] -In the object. -.IP [2] In the classes mixed into the object, in class traversal order. The list of mixins is checked in natural order. -.IP [3] +.IP [2] In the classes mixed into the classes of the object, with sources of mixing in being searched in class traversal order. Within each class, the list of mixins is processed in natural order. +.IP [3] +In the object itself. .IP [4] In the object's class. .IP [5] @@ -69,12 +77,15 @@ In the superclasses of the class, following each superclass in a depth-first fashion in the natural order of the superclass list. .PP Any particular method implementation always comes as \fIlate\fR in the -resulting list of implementations as possible. +resulting list of implementations as possible; this means that if some class, +A, is both mixed into a class, B, and is also a superclass of B, the instances +of B will always treat A as a superclass from the perspective of inheritance. +This is true even when the multiple inheritance is processed indirectly. .SS FILTERS .PP When an object has a list of filter names set upon it, or is an instance of a class (or has mixed in a class) that has a list of filter names set upon it, -before every invokation of any method the filters are processed. Filter +before every invocation of any method the filters are processed. Filter implementations are found in class traversal order, as are the lists of filter names (each of which is traversed in natural list order). Explicitly invoking a method used as a filter will cause that method to be invoked twice, once as @@ -85,7 +96,7 @@ forward to the proper implementation of the method (which it does by invoking the \fBnext\fR command as filters are inserted into the front of the method call chain) and is responsible for returning the result of \fBnext\fR. .PP -Filters are not invoked when processing an invokation of the \fBunknown\fR +Filters are not invoked when processing an invocation of the \fBunknown\fR method because of a failure to locate a method implementation, or when invoking either constructors or destructors. .SH EXAMPLES @@ -127,7 +138,7 @@ in the superclass, args = pureSynthesis after chaining from subclass before chaining from subclass, args = in the superclass, args = a b -in the superclassm args = pureSynthesis +in the superclass, args = pureSynthesis after chaining from subclass .CE .PP @@ -157,7 +168,7 @@ oo::class create cache { method flushCache {} { my variable ValueCache unset ValueCache - \fI# Skip the cacheing\fR + \fI# Skip the caching\fR return -level 2 "" } } |