Implementation of TIP #381: Call Chain Introspection and Control

1 files changed, 66 insertions, 0 deletions

diff --git a/doc/info.n b/doc/info.n
index 2126b21..cb5c6e6 100644
--- a/doc/info.n
+++ b/doc/info.n
@@ -399,6 +399,29 @@ been set (e.g. a variable declared but not set by \fBvariable\fR).
 The following \fIsubcommand\fR values are supported by \fBinfo class\fR:
 .VE 8.6
 .TP
+\fBinfo class call\fI class method\fR
+.VS
+Returns a description of the method implementations that are used to provide a
+stereotypical instance of \fIclass\fR's implementation of \fImethod\fR
+(stereotypical instances being objects instantiated by a class without having
+any object-specific definitions added). This consists of a list of lists of
+four elements, where each sublist consists of a word that describes the
+general type of method implementation (being one of \fBmethod\fR for an
+ordinary method, \fBfilter\fR for an applied filter, and \fBunknown\fR for a
+method that is invoked as part of unknown method handling), a word giving the
+name of the particular method invoked (which is always the same as
+\fImethod\fR for the \fBmethod\fR type, and
+.QW \fBunknown\fR
+for the \fBunknown\fR type), a word giving the fully qualified name of the
+class that defined the method, and a word describing the type of method
+implementation (see \fBinfo class methodtype\fR).
+.RS
+.PP
+Note that there is no inspection of whether the method implementations
+actually use \fBnext\fR to transfer control along the call chain.
+.RE
+.VE 8.6
+.TP
 \fBinfo class constructor\fI class\fR
 .VS 8.6
 This subcommand returns a description of the definition of the constructor of
@@ -504,6 +527,28 @@ class's methods, constructor and destructor).
 The following \fIsubcommand\fR values are supported by \fBinfo object\fR:
 .VE 8.6
 .TP
+\fBinfo object call\fI object method\fR
+.VS 8.6
+Returns a description of the method implementations that are used to provide
+\fIobject\fR's implementation of \fImethod\fR.  This consists of a list of
+lists of four elements, where each sublist consists of a word that describes
+the general type of method implementation (being one of \fBmethod\fR for an
+ordinary method, \fBfilter\fR for an applied filter, and \fBunknown\fR for a
+method that is invoked as part of unknown method handling), a word giving the
+name of the particular method invoked (which is always the same as
+\fImethod\fR for the \fBmethod\fR type, and
+.QW \fBunknown\fR
+for the \fBunknown\fR type), a word giving what defined the method (the fully
+qualified name of the class, or the literal string \fBobject\fR if the method
+implementation is on an instance), and a word describing the type of method
+implementation (see \fBinfo object methodtype\fR).
+.RS
+.PP
+Note that there is no inspection of whether the method implementations
+actually use \fBnext\fR to transfer control along the call chain.
+.RE
+.VE 8.6
+.TP
 \fBinfo object class\fI object\fR ?\fIclassName\fR?
 .VS 8.6
 If \fIclassName\fR is unspecified, this subcommand returns class of the
@@ -672,6 +717,27 @@ method and get how it is defined. This procedure illustrates how:
 .PP
 .CS
 proc getDef {obj method} {
+    foreach inf [\fBinfo object call\fR $obj $method] {
+        lassign $inf calltype name locus methodtype
+        # Assume no forwards or filters, and hence no $calltype
+        # or $methodtype checks...
+        if {$locus eq "object"} {
+            return [\fBinfo object definition\fR $obj $name]
+        } else {
+            return [\fBinfo class definition\fR $locus $name]
+        }
+    }
+    error "no definition for $method"
+}
+.CE
+.PP
+This is an alternate way of implementing the definition lookup is by manually
+scanning the list of methods up the inheritance tree. This code assumes that
+only single inheritance is in use, and that there is no complex use of
+mixed-in classes:
+.PP
+.CS
+proc getDef {obj method} {
     if {$method in [\fBinfo object methods\fR $obj]} {
         # Assume no forwards
         return [\fBinfo object definition\fR $obj $method]