From 03b2d87e3609bcff1bf1056cacecad8847bcad1c Mon Sep 17 00:00:00 2001
From: Erich Eckner <git@eckner.net>
Date: Thu, 14 Dec 2017 12:50:43 +0100
Subject: matheunit.pas: tKnownValues haben jetzt einen Vorgesetzten

---
 matheunit.pas | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 66 insertions(+), 6 deletions(-)

diff --git a/matheunit.pas b/matheunit.pas
index d5f9de7..71005c5 100644
--- a/matheunit.pas
+++ b/matheunit.pas
@@ -16,17 +16,21 @@ type
   end;
   tKnownValues = class
   private
-    kvs: array of tKnownValue;
+    chef:    tKnownValues;
+    knechte: array of tKnownValues;
+    kvs:     array of tKnownValue;
     function finde(nam: string): longint; inline;
   public
-    constructor create; overload;
-    constructor create(original: tKnownValues); overload;
+    constructor create(chf: tKnownValues);
+    constructor createFromOriginal(original: tKnownValues);
     destructor destroy; override;
     procedure add(val: tKnownValue); inline; overload;
     procedure add(nam: string; val: extended); overload;
     function rem(nam: string): boolean;
     function extract(nam: string; out val: extended): boolean; inline;
     procedure dump(prot: tProtokollant; prefix: string);
+    procedure neuerKnecht(knecht: tKnownValues);
+    procedure entferneKnecht(knecht: tKnownValues);
   end;
 
 function plus(a,b: tExtPoint): tExtPoint;
@@ -59,26 +63,47 @@ implementation
 
 // tKnownValueArray ************************************************************
 
-constructor tKnownValues.create;
+constructor tKnownValues.create(chf: tKnownValues);
 begin
   inherited create;
   fillchar(kvs,sizeOf(kvs),#0);
+  fillchar(knechte,sizeOf(knechte),#0);
   add('π',pi);
+  chef:=chf;
+  if assigned(chef) then
+    chef.neuerKnecht(self);
+  setLength(knechte,0);
 end;
 
-constructor tKnownValues.create(original: tKnownValues);
+constructor tKnownValues.createFromOriginal(original: tKnownValues);
 var
   i: longint;
 begin
   inherited create;
   fillchar(kvs,sizeOf(kvs),#0);
+  fillchar(knechte,sizeOf(knechte),#0);
   for i:=0 to length(original.kvs)-1 do
     add(original.kvs[i]);
+  chef:=original.chef;
+  if assigned(chef) then
+    chef.neuerKnecht(self);
 end;
 
 destructor tKnownValues.destroy;
+var
+  i: longint;
 begin
   setLength(kvs,0);
+  for i:=0 to length(knechte)-1 do begin
+    knechte[i].chef:=chef;
+    if assigned(chef) then
+      chef.neuerKnecht(knechte[i]);
+  end;
+  setLength(knechte,0);
+  if assigned(chef) then begin
+    chef.entferneKnecht(self);
+    chef:=nil;
+  end;
   inherited destroy;
 end;
 
@@ -135,7 +160,10 @@ begin
   i:=finde(nam);
   result:=i>=0;
   if result then
-    val:=kvs[i].value;
+    val:=kvs[i].value
+  else
+    if assigned(chef) then
+      result:=chef.extract(nam,val);
 end;
 
 procedure tKnownValues.dump(prot: tProtokollant; prefix: string);
@@ -144,6 +172,38 @@ var
 begin
   for i:=0 to length(kvs)-1 do
     prot.schreibe(prefix+kvs[i].name+' = '+floattostr(kvs[i].value));
+  if assigned(chef) then
+    chef.dump(prot,prefix+' chef: ');
+end;
+
+procedure tKnownValues.neuerKnecht(knecht: tKnownValues);
+var
+  i: longint;
+begin
+  for i:=0 to length(knechte)-1 do
+    if knechte[i]=knecht then
+      fehler('tKnownValues soll einen Knecht hinzufügen, den es schon hat!');
+  setLength(knechte,length(knechte)+1);
+  knechte[length(knechte)-1]:=knecht;
+end;
+
+procedure tKnownValues.entferneKnecht(knecht: tKnownValues);
+var
+  i: longint;
+begin
+  i:=0;
+  while i<length(knechte) do begin
+    if knechte[i]=knecht then begin
+      while i<length(knechte)-1 do begin
+        knechte[i]:=knechte[i+1];
+        inc(i);
+      end;
+      setLength(knechte,length(knechte)-1);
+      exit;
+    end;
+    inc(i);
+  end;
+  fehler('tKnownValues soll einen Knecht entfernen, den es nicht hat!');
 end;
 
 // allgemeine Funktionen *******************************************************
-- 
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