code.delx.au - gnu-emacs/blob - test/etags/objcpp-src/SimpleCalc.M

   1 //      SimpleCalc -- Randy Nelson -- NeXT Developer Training
   2 //      A general class that serves as a liaison between a calculator interface
   3 //      and a calculator engine.
   4 //
   5 //      You may freely copy, distribute and reuse the code in this example.
   6 //      NeXT disclaims any warranty of any kind, expressed or implied, as to
   7 //      its fitness for any particular use.
   8 //
   9 //      Created 8-22-90
  10 //
  11 //      C++ "linkage" directive - tells the C++ compiler that the following
  12 //      interface files contain Objective-C code.
  13
  14 extern "Objective-C"
  15 {
  16 #import <appkit/Application.h>
  17 #import <appkit/Panel.h>
  18 #import <appkit/TextField.h>
  19 #import <appkit/Button.h>
  20 }
  21
  22 extern "C"
  23 {
  24 #import <appkit/publicWraps.h>
  25 #import <objc/error.h>
  26 #import <objc/NXStringTable.h>
  27 #import <strings.h>
  28 }
  29
  30 //      The C++ "linkage" directive serves two purposes (when importing
  31 //      interface files that contain straight ANSI-C/Objective-C code). It:
  32 //
  33 //      (a) allows you to link with libraries that have not been compiled with
  34 //      the C++ compiler. Since libraries on the NeXT computer are compiled
  35 //      with the Objective-C compiler (cc, not cc++), you must use the C++
  36 //      linkage directive when importing interface files that represent NeXT
  37 //      libraries (or any library that is not compiled with cc++).
  38 //
  39 //      (b) tells the compiler to ignore C++ keywords that will result in
  40 //      syntax errors when importing ANSI-C/Objective-C interface files.
  41 //      The linkage directive essentially tells the C++ compiler to treat
  42 //      keywords (such as "new", "delete", etc.) as normal identifiers.
  43
  44 #import "SimpleCalc.h"
  45 #import "CalcEngine.h"
  46 #import "InfoManager.h"
  47
  48 @implementation SimpleCalc
  49
  50 // Initialize an instance of the SimpleCalc class.  One instance variable of
  51 // that class is the C++ calculator engine.
  52 - init
  53 {
  54     cplus_object = new CalcEngine; // new is a keyword in C++.
  55     previousAction = 0;
  56     return self;
  57 }
  58
  59 // Append a new digit entered by the user to the text field display.
  60 - appendToDisplay:(const char *)theDigit
  61 {
  62     char *copyOfDisplay = NXCopyStringBuffer([display stringValue]);
  63
  64     [display setStringValue: strcat(copyOfDisplay, theDigit)];
  65
  66     return self;
  67 }
  68
  69 // We need to keep a history of one action to make decisions about the display.
  70 - registerAction:(SEL)action
  71 {
  72     previousAction = action;
  73     return self;
  74 }
  75
  76 // The user has pushed the decimal key on the calculator.
  77 - decimalKey:sender
  78 {
  79     if (previousAction == @selector(operationKeys:))
  80         [display setStringValue:"."];
  81     else {
  82         if (strchr([display stringValue], '.'))
  83             NXBeep();
  84         else
  85             [self appendToDisplay:"."];
  86     }
  87     return [self registerAction:_cmd];
  88 }
  89
  90 // One of the number keys was selected by the user.
  91 - numberKeys:sender
  92 {
  93     char aDigit[2];
  94     int digit = [sender selectedTag];
  95
  96     sprintf(aDigit, "%d", digit);
  97
  98     if (previousAction == @selector(operationKeys:) ||
  99         previousAction == @selector(equalsKey:))
 100     {
 101         [display setStringValue:aDigit];
 102     } else {
 103         if ([display doubleValue] == 0 && !strchr([display stringValue], '.'))
 104             [display setStringValue:aDigit];
 105         else
 106             [self appendToDisplay:aDigit];
 107     }
 108     return [self registerAction:_cmd];
 109 }
 110
 111 // The user pressed the equals key on the calculator interface.
 112 - equalsKey:sender
 113 {
 114     if (previousAction == 0)
 115         NXBeep();
 116     else {
 117         NX_DURING
 118             [display setDoubleValue:
 119                 cplus_object->equalsKey([display doubleValue])];
 120         NX_HANDLER
 121             NXRunAlertPanel(
 122                 [myNXStringTable valueForStringKey:"operationFailed"],
 123                 [myNXStringTable valueForStringKey:NXLocalHandler.data1],
 124                 [myNXStringTable valueForStringKey:"OK"], NULL, NULL);
 125         NX_ENDHANDLER
 126     }
 127     return [self registerAction:_cmd];
 128 }
 129
 130 // The user pressed one of the operation keys.
 131 - operationKeys:sender
 132 {
 133     if (previousAction == 0)
 134         NXBeep();
 135     else if (previousAction == @selector(operationKeys:))
 136         cplus_object->setOperation([sender selectedTag]);
 137     else {
 138         NX_DURING
 139             [display setDoubleValue:
 140                 cplus_object->operationKeys([sender selectedTag],
 141                                             [display doubleValue])];
 142         NX_HANDLER
 143             NXRunAlertPanel(
 144                 [myNXStringTable valueForStringKey:"operationFailed"],
 145                 [myNXStringTable valueForStringKey:NXLocalHandler.data1],
 146                 [myNXStringTable valueForStringKey:"OK"], NULL, NULL);
 147         NX_ENDHANDLER
 148     }
 149     return [self registerAction:_cmd];
 150 }
 151
 152 // User pressed the Clear key.
 153 - clearKey:sender
 154 {
 155     [display setStringValue:"0"];
 156     return self;
 157 }
 158
 159 // User pressed the Clear All key.
 160 - clearAllKey:sender
 161 {
 162     cplus_object->clear();
 163     [self registerAction:0];
 164     return [self clearKey:sender];
 165 }
 166
 167 // Called just after the application initializes and starts up.
 168 - appDidInit:sender
 169 {
 170     // Set the Enter key on the keypad to be equivalent to the = key.
 171     [[display window] addToEventMask:NX_SYMBOLSET];
 172     [enterKey setKeyEquivalent:3];
 173     [[display window] makeKeyAndOrderFront:self];
 174     return self;
 175 }
 176
 177 // Called just before the window closes.
 178 - windowWillClose:sender
 179 {
 180     return [NXApp terminate:self];
 181 }
 182
 183 // Brings up the Info panel.   Not done on startup because it's in a separate
 184 // interface file.  Saves startup time for the user if we do this when they ask
 185 // for it, and not before.
 186 - infoPanel:sender
 187 {
 188     if(infoManager == nil){
 189         infoManager = [[InfoManager alloc] init];
 190     }
 191     [infoManager orderInfoPanelFront:sender];
 192     return self;
 193 }
 194
 195 // Brings up the Help panel.   Not done on startup because it's in a separate
 196 // interface file.  Saves startup time for the user if we do this when they ask
 197 // for it, and not before.
 198 - helpPanel:sender
 199 {
 200     if(infoManager == nil){
 201         infoManager = [[InfoManager alloc] init];
 202     }
 203     [infoManager orderHelpPanelFront:sender];
 204     return self;
 205 }
 206
 207 @end