Chelper: what changed

Revision 1 to 2. Removed lines have a minus sign; added lines have a plus sign.

Old	New		Line
1	1		### About
2	2
3	3		Chelper is Lazarus extension tool, that helps converting C headers to Pascal. Yes, it's yet another C-to-Pascal converting tool like lot of similar ([[H2Pas]], ToPas), but one might find it more useful.
4	4
5	5		The extension doesn't try to convert a header for the user, instead it's a tool to help with manual translation, doing almost all of "dirty work" for the user.
6	6
7	7		Chelper also supports converting Objective-C declarations into Objective-P.
8	8
9	9		### Author
10	10
11	11		Dmitry 'skalogryz' Boyarintsev
12	12
13	13		### License
14	14
15	15		[modified](http://svn.freepascal.org/svn/lazarus/trunk/COPYING.modifiedLGPL) [LGPL](http://svn.freepascal.org/svn/lazarus/trunk/COPYING.LGPL) (same as the FPC RTL and the Lazarus LCL). You can contact the author if the modified LGPL doesn't work with your project licensing.
16	16
17	17		### Download
18	18
19	19		There's no "downloadable" package yet, you can access the tool from SVN:
20	20
21	21		<https://sourceforge.net/p/lazarus-ccr/svn/HEAD/tree/components/chelper/>
22	22
23	23		`svn checkout `[`https://svn.code.sf.net/p/lazarus-ccr/svn/components/chelper/`](https://svn.code.sf.net/p/lazarus-ccr/svn/components/chelper/)
24	24
25	25		### Change Log
26	26
27	27		- Version 0.8, 8 Aug 2010
28	28
29	29		### Dependencies / System Requirements
30	30
31	31		- Lazarus 0.9.29 or Higher
32	32
33	33		Status: Beta
34	34
35	35		### Issues
36	36
37	37		- No complete expression parser to construct the expression tree.
38	38
39	39		If you find a bug in the converter please report it to [bugs.freepascal.org](http://bugs.freepascal.org) for Lazarus-CCR project. Please attach the C-header text and the explanation what doesn't work as expected.
40	40
41	41		### Installation
42	42
43	43		- Get the package from SVN
44	44		- Install Chelper.lpk package to the Lazarus.
45	45		- Go to Tools-\>C to Pascal Options-\>Converter, uncheck Use external converter if you want to use the package built-in converter.
46	46
47	47		Using built-in converter has an advantage of the performance. However, if you'll need to update converter, you'll need to rebuild the whole IDE. It's also possible that converter might cause crashes or hangs. You should bug report it, but you're risking to loose all of your data.
48	48
49	49		It's much safer to use the external cconvert tool. It's also easier to update the converter if a new features are added or bugs fixed. All you need is to rebuild the cconverter executable a lot of faster than rebuilding Lazarus.
50	50
51	51		To use the external tool, you need to do the following:
52	52
53	53		- Open and build cconvert.lpi project (located at the package directory). You should get "cconvert" executable file.
54	54		- Open Tools-\>C to Pascal Options-\>Converter, press Select and choose cconvert executable file.
55	55		- Check Use external converter at Tools-\>C to Pascal Options-\>Converter
56	56
57	57		### How to use
58	58
59	59		#### Shortkeys
60	60
61	61		- ctrl+b - convert a single C declaration to Pascal
62	62		- ctrl+shift+b - convert all C declarations to Pascal from the current cursor position to the end of the file.
63	63
64	64		#### General
65	65
66	66		- Open a file with C declarations in Lazarus IDE or start a new file copying declarations there
67	67		- Place the cursor at the line where C declaration and press Ctrl+B (the shortcut would be modifiable in future).
68	68
69	69		for example:
70	70
71	71		`int c;`\
72	72		`int b; `
73	73
74	74		if the cursor placed at 'inc c;' line and ctrl+b pressed the result would be:
75	75
76	76		`var`\
77	77		` c : Integer;`\
78	78		`int b;`
79	79
80	80		exactly one definition is converted. The cursor would be place right after the converted definition. You can press ctrl+b again, and the result would be:
81	81
82	82		`var`\
83	83		` c : Integer;`\
84	84		`var `\
85	85		` b : Integer;`
86	86
87	87		Parsing definitions one-by-one will get your C headers ready with a very short period of time, as well as keeping it clean and correct from Pascal point of view.
88	88
89	89		- If you're sure your defines (explained below) are configured well enough. You can try to convert the rest of the file in one call by pressing ctrl+shift+b
90	90
91	91		i.e. you have 2 declarations in the file:
92	92
93	93		`int fn(int, float);`\
94	94		`extern int v;`
95	95
96	96		placing the cursor before them and pressing ctrl+shift+b, would generate.
97	97
98	98		`function fn(par0: Integer; par1: Single): Integer; cdecl; external;`\
99		-	\
	99	+
100	100		`var`\
101	101		` v : Integer; external;`
102	102
103	103		You must be careful, because it's common to use macros in C headers. Leaving any of macros undefined might produce wrong pascal declaration. The next section explains how to define a macro for the chelper.
104	104
105	105		#### Defines
106	106
107	107		In most cases parameterless macro definitions, like
108	108
109	109		`#define VALUE 1 << 2;`
110	110
111	111		are used like constant values. Chelper translates them as constants trying to convert the define expression.
112	112
113	113		`const`\
114	114		` VALUE = 1 shr 2;`
115	115
116	116		In other cases defines are used for some "special" markings or additional information for external tools.
117	117
118	118		`#define LIB_DEPRECATED `\
119	119		`LIB_DEPRECATED int somefunc(int p);`
120	120
121	121		without the knowledge of LIB_DEPRECATED being the macro (of nothing), it's impossible to parse function declaration correctly. You can specify macros used by Chelper in the special defines file.
122	122
123	123		Select Tools-\>C to Pascal options-\>Main select the defines file and press Edit.
124	124
125	125		This would open the custom defines file in Lazarus IDE. All macros declared at this file are used by Chelper. After adding/editing macro defines save the file and you can return to the C header converting.
126	126
127	127		Chelper handles parameter macros as well.
128	128
129	129		`int somefunc SAFE_PARAMS( (int i))`
130	130
131	131		adding the the following declaration into defines file
132	132
133	133		`#define SAFE_PARAMS(x) x`
134	134
135	135		will allow to parse the declaration correctly
136	136
137	137		`function somefunc(i: Integer): Integer;`
138	138
139	139		#### Configuration File
140	140
141	141		Configuration file represents itself a simple .ini file. Following section are used in the file:
142	142
143	143		- Main - for general declarations, that effects
144	144
145	145		- Types - custom type conversion section. Name=Value, where Name is the c-type name, Value is resulting pascal type
146	146
147	147		example:
148	148
149	149		`[Types]`\
150	150		`int=integer`\
151	151		`int*=PInteger`\
152	152		`float=single`\
153	153		`float*=PSingle`
154	154
155	155		---
156	156		From the Free Pascal wiki, page "Chelper", as it stood on 2022-04-30 after a change by E-ric, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).

Back to history