Difference between revisions of "Code Conversion Guide/ja"

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====Lazarus上でのDelphi VCL, Kylix CLXのソース====
 
====Lazarus上でのDelphi VCL, Kylix CLXのソース====
 
+
DelphiやKylixのソースを変換しているとき、特定の機能の関数がなにをやっているか、宣言を探すことは、よく役に立ちます。LazarusのIDEは、DelphiやKylixのソースコードを解析できます。これをするためには、検索パスとコンパイラ設定をきちんとおこなわなくてはなりません。これらは、Environment->CodeTools Defines Editor->Insert Templateで簡単におこなうことができます。
When converting Delphi/Kylix sources, it is often useful to do a find declaration to see, what a specific function is doing. The Lazarus IDE can parse the Delphi/Kylix sources. To do this it needs some searchpaths and compiler settings. You can easily setup this in
 
Environment->CodeTools Defines Editor->Insert Template
 
  
 
=== 変換に関する問題と解決方法 ===
 
=== 変換に関する問題と解決方法 ===

Revision as of 11:45, 16 November 2006

Deutsch (de) English (en) español (es) français (fr) 日本語 (ja) português (pt) русский (ru) slovenčina (sk)

日本語版メニュー
メインページ - Lazarus Documentation日本語版 - 翻訳ノート - 日本語障害情報

このページでは、すでにDelphiやKylixで書いたコードを Free PascalコンパイラやLazarus IDEで動くようにするための方法を説明します。 LazarusとFree PascalコンパイラはDelphiやKylixと同じ方向性をもっていますが、LazarusやFree Pascalは、それらのクローンではありません。 沢山のライブラリコールや使い方に違いがあります。そして、いくつかの場面において、FPCは拡張されており、また、より正しい文法を要求することがあります。

Lazarus For Delphi Users/ja を見て、機能的な違いを確認してください。

このガイドの目的は、Delphiの既存のコードをLazarusに変換するときに、よく出会う特徴的な違いを、きちんと文書化することです。

この文書はWikiの知識ベースに置かれていますので、だれでも問題に出会ったときに他の人にも知らせることができるよう、拡張できます。

変換時のコンポーネントやライブラリの選択

変換するコードの場所を見つける

ネット上には、変換すればFPCやLazarusで使える、沢山の利用可能なコードがあります。たとえば、このページPage Of Code Sitesがスタートとなるでしょう。他のもっといいコードサイトのURLなどを知っていれば書き加えてください。

TurboPowerソフトウエア社は、最近彼らの商用製品をMPLのライセンスの元でリリースしました。使えるパッケージは、http://sourceforge.net/users/tpsfadmin/ ここ]にあります。 作業が重複するのを避けるため、変換されたパッケージはComponents and Code examplesページにあります。 もし、あなたが変換したパッケージや、変換中のものがあれば、Current conversion projects ページに書き加えてください。

ライセンス

Licenses for existing code range from freeware/public domain to restrictive versions that prohibit modification, re-distribution and commercial use. Before converting any package, it's a good idea to examine its licensing and make sure it's going to be compatible with Lazarus and the Free Pascal Compiler. License selection is especially important with components since dropping one on a form can impose an unwanted or incompatible license on an entire application.

When converting components, please respect the wishes of the original author and retain all copyright and licensing headers along with email addresses and url's. It's courteous and often useful to inform the author that their component is being converted... especially if the component is under a restrictive license. New interest in an old or forgotten component can sometimes inspire authors to revise their original and overly restrictive licensing.

In general, Public Domain (freeware), and the LGPL/MPL are the the most flexible for distributing components. For more information, the Open Source Definition is a good place to start. There are also several comparisons available to help clarify how the various types of licenses work and what impact they'll have on code they're linked to. Search for "open source license comparison"

依存関係

変換をはじめる前のもう一つのステップは、それらのコードが、利用できないか、簡単には変換できそうもない他のパッケージと深い依存関係をもっていないことを確認することです。 いくつかのフリーウエアはいまや使われないような利用できないパッケージや、あるいは適切でないライセンスをもつパッケージと結合しているか、拡張されていることがあります。

コンパイラの問題

下記を見てください:

プラットホームとOSの問題

LazarusとFree Pascal Compilerはクロスプラットホームであり、クロスプラットホームアーキテクチャ開発ツールです。DelphiのほとんどのコードはWin32でのインテルCPUで実行されるように設計されていることと比較してみてください。 もし、あなたのコンポーネントが多くのWin32に特化したコードを使っていれば、すこしでもプラットホームに依存しないようにしてみることをお勧めします。 しかし、多くのWindowsに特化したコードをつかっているからといって、LCLに挑戦することをやめないでください。本当にLCLはすばらしい機能を提供しています。

変換をおこなう

変換するプロジェクトのためのLazarusの環境を設定する

テストプロジェクトを作成する

  • サブディレクトリ(例: convertdir)に、変換されるほうのコードを置く。
  • Lazarusを起動する
  • File->Save All でthe convertdirのサブディレクトリに保存する。 プロジェクト名に意味の名前を付ける。デフォルトユニットの名前をつけるのは好きにしてよい。
  • converdirで、変換するメインとなるユニットを開く。
  • それをプロジェクトに加える。: Project->Add Active Unit
  • Run Tools->Quick Syntax Check をするか、 Run Build All で開始してみる。

最初に目を向ける事柄

  • 1.0.x系のコンパイラでは、ファイル名は大文字小文字を判別します。もし、このバージョンで作業していたら、全ファイル名を小文字にしてください。そうしなかったら、 "File not found" エラーになります。

Lazarus上でのDelphi VCL, Kylix CLXのソース

DelphiやKylixのソースを変換しているとき、特定の機能の関数がなにをやっているか、宣言を探すことは、よく役に立ちます。LazarusのIDEは、DelphiやKylixのソースコードを解析できます。これをするためには、検索パスとコンパイラ設定をきちんとおこなわなくてはなりません。これらは、Environment->CodeTools Defines Editor->Insert Templateで簡単におこなうことができます。

変換に関する問題と解決方法

LazarusでのDelphi / Kylix ファイルとの対応

Delphi / Kylix Lazarus Description
.pas

.dfm / .xfm .dcu / .dpu .dpr (main project file) .res .dof / .kof --- --- ---

.pas, .pp

.lfm .o .lpr --- --- .lrs .lpi (main project file) .ppu

Pascal unit file

Form data file Compiled unit file Project file Resource file Project options file Lazarus resource file Lazarus project information file FPC unit description file

Delphi プロジェクト/フォーム/ユニットを Lazarus に変換する

Rename or copy the .dpr file to a .lpr file. Comment out or remove the

{$R *.res}

directive and add a

{$mode delphi}{$H+}

or

{$mode objfpc}{$H+}

directive to the .lpr file. The Lazarus IDE can assist in this conversion through the Tools menu item "Convert Delphi Project to Lazarus Project". It asks for a .dpr (Delphi Project) file and converts it to .lpr; furthermore, it creates the .lpi file and converts all units.

Many existing Delphi forms can be converted to work with Lazarus by using the IDE's built in .dfm to .lfm form converter. It can be found under the Tools menu item as "Convert DFM file to LFM". Bring up the file dialog, select the dfm and the converter will do the rest.

If you need to convert the whole unit (with or without a form), Lazarus also includes a built in "Convert Delphi unit to Lazarus unit" which will do the following for you -

  1. fixes the case of include filenames and uses sections.
  2. converts .dfm file to .lfm file (currently without content check, just format)
  3. creates an empty .lrs file (the content will be created later)
  4. adds
    {$mode delphi}
    directive
  5. replaces windows unit with LCLIntf
  6. adds LResources unit if needed (i.e., if unit.lrs is to be used;
    uses LResources
    can be in the implementation part)
  7. removes variants unit
  8. removes
    {$R *.dfm}
    directive
  9. adds initialization section and
    {$i unit.lrs}
    directive

This allows quick and easy conversion of most units from Delphi format to Lazarus format. It does not do any validity check, or automatic syntax changes, so any syntax changes you need to make, additional unit/unit name changes, or dfm/pas changes for control/component differences you must still do manually, though in time some wizards to help facilitate some of this, especially the repairing of converted forms(lfm), may become available.

正しいコンパイラモードを選択する

The Free Pascal Compiler supports 5 different pascal modes. For example TP for turbo pascal, lets you compile turbo pascal units. There is also a DELPHI compatibility mode that can be set to make existing code easier to convert. Lazarus prefers the OBJFPC mode, which almost equals the DELPHI mode, but is less ambigious than the Delphi syntax. Here are the important points:

The mode can be selected at command line or at the start of the source. Using the command line has the advantage, that you don't need to change the source, but the disadvantage, that others must be told.

Most Delphi units can be compiled by the Free Pascal compiler by adding

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}

right after the unit name.

For more details about Free Pascal modes see the Free Pascal Documentation

クロスプラットホームでの考慮

  • Inline assembler is always a problem because it will bind the code to the Intel architecture. Some developers do algorithm prototypes in Pascal and ifdef the their optimized assembler. Fortunately TurboPower did this in numerous places with their code. If this is the case with the package you're converting, throw the switch back to Pascal.
  • Don't reference specific memory location like the BIOS data area. Find out what the code needs and try to find a cross platform alternative.
  • Don't do processor specific tricks (like using the Intel TSC) without enclosing your code in an ifdef for the platform the code needs... and providing an alternative for environments that don't have the hardware capability.
  • If you need some OS specific code, then you can use IFDEFs. See below for a list of macros.

便利なコンパイラ変数

To write code, that behaves on different systems differently, you can use the

{$IFDEF Name}

directives.

  • {$IfDef LCL}

This variable is defined, when using the LCL package. Useful to write code, that works with the LCL and Delphi.

  • {$IfDef LCLGtk}
    ,
    {$IfDef LCLWin32}
    ,
    {$IfDef LCLQt}
    , ...

This variable is defined, when using the LCL package and the specific widgetset is currently used. Useful to write code, that works with the LCL on a specific platform.

  • {$IfDef FPC}

This variable is defined, when using the FPC compiler. Useful to write code, that works with FPC and Delphi.

  • {$IfDef Unix}
    ,
    {$IfDef Win32}
    , ...

Defined by FPC for the current Target OS. Delphi defines "Linux", "Win32" and "MSWindows". Free Pascal runs on much more platforms and so it is recommended to use the more general items. For example "Unix" is defined for Linux, FreeBSD, NetBSD and OpenBSD, where Lazarus already runs. Use

{$IfDef Linux}
  {$Define Unix}
{$EndIf}

to work around this for Kylix.

For more details see the Free Pascal Documentation.

失った識別子を見つける

There are differences in how the LCL is organized when compared to the Delphi VCL. If you get a "not found" compiler error about a major class or identifier, the chances are good that it's in a different unit. A complete cross reference can be found by grep'ing lazarus/docs/xml or the lcl subdirectory.

For example the commonly used tbutton typically throws an error in Delphi code because it's located in a unit named buttons.pp. The following command finds the correct unit very quickly (in the lazarus source directory):

 grep -in ' tbutton =' lcl/*


LazarusとDelphiの主要なユニットの違い

Please add to this topic!

  • Windows->Interfaces, LCLIntf, LCLType, LCLProc, VCLGlobals, ...)

As the LCL is not windows specific, the code that is in the Delphi Windows unit for directly accessing the Win32 API is abstracted into seperate interfaces, which can be accessed from the LCLIntf unit. Keep in mind, that Lazarus does not emulate win32, so many functions are missing and some do not work as their win32 counterparts. These functions only exist for Delphi compatibility and should only be used for quick & dirty porting. LCL also breaks out many of the types, so often LCLType, and sometimes VCLGlobals are required. LCLProc also contains a few functions which can be useful for lower level handling such as "FreeThenNil" as is in Delphi 5 and higher, "DeleteAmpersands" to remove additional ampersands from a string for controls(& vs && etc). The Interfaces unit needs to be included in the .lpr file to initialize the appropriate widgetset.

  • Messages->LMessages

TControl Messages for win32 event callbacks of the format WM_CALLBACK and the structs associated with them are often found in the Messages unit in Delphi. In the LCL these types of messages and there structs are usually found in LMessages, usually with name changes of WM to LM, so for instance WM_MOUSEENTER becomes LM_MOUSEENTER, and TWMMouse becomes TLMMouse.

  • Graphics, Controls->GraphTypes, GraphMath, Graphics, Controls

To simplify some things and break complexity of circles between units, a few types have been abstracted into a shared unit called GraphType, which includes things, which in Delphi are located in Graphics or Controls, for instance the bvNone etc of panels. So sometimes you have to include it. Also a unit which, although incompatible with Delphi, adds other useful functionality is GraphMath, which adds a TFloatPoint for precision, misc routines for dealing with beziers, lines, and arcs, as well as some operator overloading for use with TPoints and TRect, such as for instance Point1 := Point2 + Point3, and comparing two rects like if (rect1 = rect2) then ...

  • Mask->MaskEdit

For more intelligent naming considerations, the unit for TMaskEdit is called [MaskEdit|] instead of the slightly more nebulous Mask as in many versions of Delphi.

  • StdCtrls->StdCtrls,Buttons

In many version of Delphi TButton is located in StdCtrls, while TSpeedButton and TBitBtn are in Buttons. For consistency and simplicity the LCL puts all button types in Buttons, which can occasionally break code conversion, so it is always a good idea to include.

Delphiのプロパティとメソッドの違い -> FPC/LCL

  • TBitmap contains a canvas in the LCL


文法上の違い

Please add to this topic!

Because of the inherent strictness in FPC, some syntax changes are necessary, even though

{$Mode Delphi}

does allow more laziness like Delphi does. For this reason complying as much with the syntax rules of

{$Mode ObjFPC}

as possible is highly recommended, even when the codebase is still going to be shared between Delphi and the LCL. Some of these are simply better coding practices, and sometimes because Delphi mode is not entirely accurate, or in a few instances Delphi acceptible code does not function as expected with FPC, even though it might compile. To that end even though not all such are strictly required, the following list of changes should be considered mandatory :


When assigning an event handling entry point, prefix it with an "@"

For instance, you might assign a button callback manually

Delphi FPC
begin
if not
Assigned(MyButton.OnClick)
then
MyButton.OnClick:= SomeFunction;
//@ not required
//more code...
end
;
begin
if not
Assigned(MyButton.OnClick)
then
MyButton.OnClick:= @SomeFunction;
//@ IS required
//more code...
end
;
When calling a procedure variable use this syntax
theprocname()

In Delphi there is no difference between a function result and a variable, however there is in FPC, so to call a function, even if it has no parameters, you must append parenthesis. For Example -

Delphi FPC
With
(SomeObject)
do begin
If
Assigned(OnMyCallback)
then
OnMyCallback;
//parenthesis not required
end
;
With
(SomeObject)
do begin
If
Assigned(OnMyCallback)
then
OnMyCallback();
//parenthesis required
end
;
When accessing values in a pointer to a record you must dereference first

In Delphi it is not required to de-reference a pointer to a record to access values within it, it can, in fact, be treated just like the record itself, or any other object. In FPC it must be first de-referenced. As an example,

Delphi FPC
Function
GetSomeValue(ARecord: PMyRecord)
:
Integer;
begin
If
Assigned(ARecord)
then
Result
:=
ARecord.SomeValue
else
Result:=
0
;
end
;
Function
GetSomeValue(ARecord: PMyRecord)
:
Integer;
begin
If
Assigned(ARecord)
then
Result
:=
ARecord^.SomeValue
else
Result:=
0
;
end
;
When accessing chars of an indexed string Property of an object, it must be enclosed in parentheses

With Delphi it is possible to treat a Property exactly like some other const or var, even to accessing for instance individual chars of a string directly, while this is not always possible in FPC, specifically for indexed properties. Instead it must be enclosed in parentheses, to make distinct. While this may not always hold true it is probably a good practice to consider anyway. For example

Delphi FPC
Type
TSomeComponent=
class
(TComponent)
//More code...
Published
Property
MyString:
String
index
3
read
GetMyString;
//More code...
End
;
var
MyChar
:
char;
begin
If
Length(MyString)>
2
then
//no parenthesis needed
MyChar:= MyString[
3
];
//More code...
end
;
Type
TSomeComponent=
class
(TComponent)
//More code...
Published
Property
MyString:
String
index
3
read
GetMyString;
//More code...
End
;
var
MyChar
:
char;
begin
If
Length(MyString)>
2
then
//parenthesis sometimes needed
MyChar:= (MyString)[
3
];
//More code...
end
;


You must typecast pointers to actual type when using with var or function of that type

Sometimes in Delphi you will have a null pointer variable representing an object. While it might seem a complex situation, it is oddly quite common especially in large component packs as a method of preventing too many circular includes between objects in different units. In Delphi it is then possible to send this null pointer to a function expecting that object, without bothering to typecast to actual type, in fpc you must typecast.

For example -

Delphi FPC
Unit 1
Type
TSomeObject=
class
(TComponent)
//More code...
End
;
Procedure
DoSomething(Value: TSomeObject);
Function
GetSomeObject: TSomeObject;
Unit 2
Type
TSomeComponent=
class
(TComponent)
//More code...
Published
SomeObject: Pointer
;
//More code...
End
;
Application
var
MyComponent: TSomeComponent
;
begin
MyComponent.SomeObject
:=
GetSomeObject;
//More code...
DoSomething(MyComponent.SomeObject)
;
end
;
Unit 1
Type
TSomeObject=
class
(TComponent)
//More code...
End
;
Procedure
DoSomething(Value: TSomeObject);
Function
GetSomeObject: TSomeObject;
Unit 2
Type
TSomeComponent=
class
(TComponent)
//More code...
Published
SomeObject: Pointer
;
//More code...
End
;
Application
var
MyComponent: TSomeComponent
;
begin
MyComponent.SomeObject
:=
Pointer(GetSomeObject);
//More code...
DoSomething(TSomeObject(MyComponent.SomeObject))
;
end
;

リソース

Delphi resource files are win32 specific and not compatible with Lazarus, so you'll have to recreate and compile them using the lazres. Lazres can be found in the lazarus/tools subdirectory. If you've downloaded the Lazarus sources, you'll need to compile it first.

  • cd lazarus/tools
  • make install

To add a resource to your application:

  • lazres myresource.lrs mypix.xpm anotherpix.xpm
  • Add the LResources unit to your Uses clause
  • Include the .lrs file you created under the initialization block

Example:

function
TForm1.LoadGlyph(
const
GlyphName:
String
): TBitMap;
begin
Result:= TPixmap.Create
;
Result.LoadFromLazarusResource(GlyphName)
;
end
;
//More code...
begin
Speedbutton1.glyph:= LoadGlyph('mypix')
;
//More code...
end
;
initialization
{$I unit1.lrs}
{$I myresource.lrs}
end
.



DelphiやKylixプロジェクトをLazarusに変換する他の方法

  • Rename or copy all .dfm or .xfm files to .lfm (Early Delphi versions do not produce a text-based .dfm file. The convert utility, if present in the \bin folder can be used to covert the .dfm first))
  • Rename or copy .dpr file to .lpr
  • Make necessary changes to .lpr file:
  1. Add {$mode delphi}{$H+} or {$mode objfpc}{H+} directives
  2. Add 'Interfaces' to uses clause
  3. Comment out or delete {$R *.res} or directive
  • Make necessary changes to all .pas unit files:
  1. Add {$mode delphi}{$H+} or {$mode objfpc}{H+} directives
  2. Add 'LResources', and if the form has buttons, add 'Buttons' to uses clause
  3. Comment out or delete {$R *.dfm} or {$R *.xfm} directive
  4. Add 'Initialization' section at the end of each unit file, and add {$I unitname.lrs} directive in it
  • Select Project->New Project form file
  • Select the .lpr file
  • At 'Create a new project' window, choose 'Application'
  • Build project and make further necessary corrections to get proper compilation, at this point the .lpi file is generated automaticaly. You may also get 'Error reading Form' messages, click on 'Continue Loading' if you do.
  • Save all, and you have a Lazarus project :-)

ヘルプを見つける

If you encounter a problem during conversion that you just can't solve, there are a wide variety of places to get help. For pure Object Pascal and FPC issues, the best place to start is the Free Pascal Documentation by Michaël Van Canneyt and Florian Klämpfl. For more Lazarus oriented problems, the Lazarus Project Documentation in the Lazarus-CCR Knowledgebase Main Page is the next place to look. Finally you can post a question on any of the mailing lists for the Free Pascal Compiler or the FPC forums where a lot of experts are subscribed.

There are some outstanding search and knowledge bases online that can also be a great help for learning new techniques and solving problems. Tamarack Associates operates a fast search engine specifically for the Borland usenet archives. Mer Systems Inc. provides a similar search engine. Another outstanding source of information along with a sitewide search capability is Earl F. Glynn's Computer Lab and Reference Library.

コンポーネントをパッケージしてリリースする

コンポーネントのLazarusパッケージを作る

Creating a package makes installing the code you've converted a much easier process... especially if you're providing more then one component. Mattias Gärtner has written an overview of Lazarus Packages that should be read before beginning this process.

文書

The purpose of this site and the wiki format is to make the generation of professional documentation an easy and quick process. The wiki also makes it possible to see the results of your posting immediately and make any changes you'd like in real time.

Using the Lazarus-CCR wiki to create nice looking documentation is very easy. If you've never used wiki markup before, you can get familiar with it in the Sand Box practice area.

コードリリースページを作る

The Code Release Page contains vital information about your component that a potential downloader will need to know, such as license, intended platform, status (alpha, beta, stable...), where to download it, who wrote it, is support available... etc.

The following procedure will let you create a Code Release Page with your browser:

  • Edit the Components and Code examples page and add a project name wiki link entry for your component in the "Released Components" section. Save the modified page.
  • Go to the Component Release Template, select all and copy. Hit the back button on your browser to return to the Components and Code examples page.
  • Click on your new wiki component name entry and paste the release template into the blank edit box.
  • Edit the template accordingly and hit save.
  • Do edit-saves until your document looks the way you want it to.

Submitting the component

If you're a release technician on the project, upload your component to the SourceForge File Release System and add it to the list of release packages. Otherwise send it to one of the project administrators (Tom Lisjac or Vincent Snijders) and we'll add it to the repository.

If you think you need to continue to develop on the component, we can also put it into CVS so you'll continue to have access to it.

Contributors and Changes

This page has been converted from the epikwiki version.

  • Initial version by Tom Lisjac and Mattias Gärtner - 9/22/2003 VlxAdmin
  • Moved Getting help from the main page. T. Lisjac - 9/24/2003 VlxAdmin
  • Added documentation templates, procedure and links. 9/25/2003 VlxAdmin
  • LCLLinux was renamed to LCLIntf, Jesus Reyes, 9/27/2003
  • added more information on Unit changes, AndrewJohnson 9/27/2003
  • Updated Syntax differences, including some examples, AndrewJohnson 9/27/2003
  • FPC 1.0.x doesn't support interfaces, Vincent Snijders 9/28/2003
  • Fixed some of the examples per new WikiWord definition, 9/28/2003 VlxAdmin
  • Made code more consistant to remove last accidental Pascal WikiWord definitions, AndrewJohnson 9/27/2003
  • Use tables for code examples for nice blocks, and easy side by side view of Delphi->FPC differences, AndrewJohnson 10/17/2003
  • Use pascal stylesheet to make example code more readable, AndrewJohnson 10/18/2003
  • Added 'Another method to convert a Delphi or Kylix project to Lazarus' section , George Lober, 2/17/2006