[fpc-pascal]inherited keyword
Can someone explain the semantic difference between *1 and *2 please? procedure A(p: Type1); begin inherited; // *1 inherited A(p); // *2 end; ? Mattias ___ fpc-pascal maillist - [EMAIL PROTECTED] http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal]inherited keyword
Mattias Gaertner wrote: Can someone explain the semantic difference between *1 and *2 please? procedure A(p: Type1); begin inherited; // *1 inherited A(p); // *2 end; ? 1: supporting a delphi bug 2: as you expect Well, the comment to 1 isn't completly true: In method handlers (declared with message XXX), a simply inherited should pass the message to the parent message handle while in usual methods it does nothing. ___ fpc-pascal maillist - [EMAIL PROTECTED] http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal]inherited keyword
Hello, > > Can someone explain the semantic difference between *1 and *2 please? > > > > procedure A(p: Type1); > > begin > > inherited; // *1 > > inherited A(p); // *2 > > end; > > > > ? > > 1: supporting a delphi bug > 2: as you expect > > Well, the comment to 1 isn't completly true: In method handlers > (declared with message XXX), a simply inherited should pass the message > to the parent message handle while in usual methods it does nothing. According to the D7 docs both types of syntaxes (sp?) are completely legal and defined such that both terms are semantically equal. snip from D7 docs: The reserved word inherited plays a special role in implementing polymorphic behavior. It can occur in method definitions, with or without an identifier after it. If inherited is followed by the name of a member, it represents a normal method call or reference to a property or field--except that the search for the referenced member begins with the immediate ancestor of the enclosing method's class. [Type 2] [...example omitted...] When inherited has no identifier after it, it refers to the inherited method with the same name as the enclosing method or, if the enclosing method is a message handler, to the inherited message handler for the same message. In this case, inherited takes no explicit parameters, but passes to the inherited method the same parameters with which the enclosing method was called. [Type 1] [...example omitted...] --- snip end Or am I misinterpreting these few lines? Probably they [the Borland guys] adapted the docs for buggy behaviour of earlier Delphi versions... =) Regards, Thomas ___ fpc-pascal maillist - [EMAIL PROTECTED] http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal]inherited keyword
On Sun, 21 Dec 2003 17:36:00 +0100 Florian Klaempfl <[EMAIL PROTECTED]> wrote: > Mattias Gaertner wrote: > > > Can someone explain the semantic difference between *1 and *2 please? > > > > procedure A(p: Type1); > > begin > > inherited; // *1 > > inherited A(p); // *2 > > end; > > > > ? > > 1: supporting a delphi bug > 2: as you expect > > Well, the comment to 1 isn't completly true: In method handlers > (declared with message XXX), a simply inherited should pass the message > to the parent message handle while in usual methods it does nothing. What do you mean with "it does nothing"? It calls the ancestor method, does it not? Back to my initial question: It is indeed about a message method. I have got a message method where "inherited;" and "inherited MethodName(Param);" is not always the same. The strange thing is: It depends on how the objects are created. Is this a bug? Mattias ___ fpc-pascal maillist - [EMAIL PROTECTED] http://lists.freepascal.org/mailman/listinfo/fpc-pascal
[fpc-pascal]How to load a png image
Hello I want to know, how to load a png image with freepascal ? There is a png libpng package shipped with FreePascal, but I cannot find any examples or docs. Or are there any onther simple image formats that can be loaded into a freepascal program ? Some suggestions would be nice. Thanks Karim -- Karim [EMAIL PROTECTED] -- http://www.fastmail.fm - Same, same, but differentÂ… ___ fpc-pascal maillist - [EMAIL PROTECTED] http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal]How to load a png image
Karim wrote: Hello I want to know, how to load a png image with freepascal ? There is a png libpng package shipped with FreePascal, but I cannot find any examples or docs. Pascal unit Libpng is just a wrapper that calls functions from libpng.so. Documentation for libpng is available at the official page of libpng, http://www.libpng.org, you will most likely be interested in this document: http://www.libpng.org/pub/png/libpng-1.2.5-manual.html Or are there any onther simple image formats that can be loaded into a freepascal program ? Well, everything can be loaded into a Pascal program... The simplest possible image format is ppm (it is just a small header + array of RGB values for each pixel) - if you are on UNIX-like system and have installed proper documentation then man ppm should give you a simple specification of ppm format. You may also take a look at it's cousins, pbm, pgm and the most general one, pnm. Regards, Michalis ___ fpc-pascal maillist - [EMAIL PROTECTED] http://lists.freepascal.org/mailman/listinfo/fpc-pascal
