3 CodingStyle - standards while programming for GNU LilyPond
7 Please use these standards while doing programming for GNU LilyPond
9 Functions and methods do not return errorcodes, but use assert for
14 A program should be light and agile, its subroutines
15 connected like a strings of pearls. The spirit and intent of
16 the program should be retained throughout. There should be
17 neither too little nor too much, neither needless loops nor
18 useless variables, neither lack of structure nor overwhelming
21 A program should follow the 'Law of Least
22 Astonishment'. What is this law? It is simply that the
23 program should always respond to the user in the way that
26 A program, no matter how complex, should act as a
27 single unit. The program should be directed by the logic
28 within rather than by outward appearances.
30 If the program fails in these requirements, it will be
31 in a state of disorder and confusion. The only way to correct
32 this is to rewrite the program.
34 -- Geoffrey James, "The Tao of Programming"
38 Definitions of classes that are only accessed via pointers
39 (*) or references (&) shall not be included as include files.
41 Include files in C++ always have the file name extension ".hh".
43 Implementation files in C++ always have the file name
46 Inline definition files always have the file name extension ".icc".
51 (append '(("\\.make$" . makefile-mode)
53 ("\\.icc$" . c++-mode)
54 ("\\.tcc$" . c++-mode)
56 ("\\.pod$" . text-mode)
67 (add-hook 'c-mode-hook
68 '(lambda ()(setq c-basic-offset 4)))
71 (add-hook 'c++-mode-hook
72 '(lambda() (c-set-style "Stroustrup")
76 If you like using font-lock, you can also add this to your F<.emacs>:
78 (setq font-lock-maximum-decoration t)
79 (setq c++-font-lock-keywords-3
81 c++-font-lock-keywords-3
82 '(("\\b\\([a-zA-Z_]+_\\)\\b" 1 font-lock-variable-name-face)
83 ("\\b\\([A-Z]+[a-z_]+\\)\\b" 1 font-lock-type-face))
86 =head2 CLASSES and TYPES:
89 AClass_name (for Abbreviation_class_name)
94 Type Class::member_type_
96 the C<type> is a Hungarian notation postfix for C<Type>. See below
101 Broken code (hardwired dependencies, hardwired constants, slow
102 algorithms and obvious limitations) should be marked as such:
103 either with a verbose TODO, or with a short "ugh" comment.
107 The source is commented in the DOC++ style. Check out doc++ at
108 http://www.zib.de/Visual/software/doc++/index.html
111 C style comments for multiline comments.
112 They come before the thing to document.
119 Long class documentation.
122 TODO Fix boring_member()
134 short memo. long doco of member()
135 @param description of arguments
138 Rettype member(Argtype);
142 data_member_ = 121; // ugh
148 Unfortunately most of the code isn't really documented that good.
151 =head2 CLASSNAMES (2)
153 A lot of classes in GNU LilyPond start with 'P', this is to distinguish
154 certain parts of GNU LilyPond: the P stands for Printer, and the P-classes
155 are supposed to be more lowlevel than the others. Example:
157 Staff uses PStaff, PScore and PCol to do the typesetting of
158 symbols. Staff is the "brains" for PStaff
160 NB: in PCursor (which is part of the library) P stands for PointerCursor
167 ///check that *this satisfies its invariants, abort if not.
170 /// print *this (and substructures) to debugging log
174 protected member. Usually invoked by non-virtual XXXX()
178 /**add some data to *this.
179 Presence of these methods usually imply that it is not feasible to this
184 /// replace some data of *this
187 =head1 HUNGARIAN NOTATION NAMING CONVENTION
189 Proposed is a naming convention derived from the so-called I<Hungarian
194 The Hungarian Notation was conceived by or at least got its name from,
195 the hungarian programmer Charles Simonyi. It is a naming convention
196 with the aim to make code more readable (for fellow programmers), and
197 more accessible for programmers that are new to a project.
199 The essence of the Hungarian Notation is that every identifier has a
200 part which identifies its type (for functions this is the result
201 type). This is particularly useful in object oriented programming,
202 where a particular object implies a specific interface (a set of
203 member functions, perhaps some redefined operators), and for
204 accounting heap allocated memory pointers and links.
208 Another fun quote from Microsoft Secrets:
211 The Hungarian naming convention gives developers the ability
212 to read other people's code relatively easily, with a minmum
213 number of comments in the source code. Jon De Vann estimated
214 that only about 1 percent of all lines in the Excel product
215 code consist of comments, but the code is still very
216 understandable due to the use of Hungarian: "if you look at
217 our source code, you also notice very few comments. Hungarian
218 gives us the ability to go in and read code..."
221 Wow! If you use Hungarian you don't have to document your software!
222 Just think of the hours I have wasted documenting while this "silver bullet"
223 existed. I feel so stupid and ashamed!
231 more keystrokes (disk space!)
235 it looks silly C<get_slu_p()>
239 it looks like code from micro suckers
243 (which) might scare away some (otherwise good?)
244 progammers, or make you a paria in the free
253 not very useful if not used consistently
257 usefullness in I<very large> (but how many classes is very large?)
270 learn about cut and paste / use emacs or vi
271 or lean to type using ten fingers
275 Use emacs dabbrev-expand, with dabbrev-case-fold-search set to nil.
279 use no, or pick less silly, abbrvs.
283 use non-ambiguous postfixes C<identifier_name_type_modifier[_modifier]>
287 Macros, C<enum>s and C<const>s are all uppercase,
288 with the parts of the names separated by underscores.
297 unsigned char. (The postfix _by is ambiguous)
326 Zero terminated c string
334 =head2 User defined types
341 Slur* slur_p = new Slur;
345 The following types modify the meaning of the prefix.
346 These are precede the prefixes:
360 const. Note that the proper order C<Type const> i.s.o. C<const Type>
364 A const pointer. This would be equivalent to C<_c_l>, but since any
365 "const" pointer has to be a link (you can't delete a const pointer),
370 temporary pointer to object (link)
374 pointer to newed object
386 Variable loop: an integer
390 Temporary variable: an unsigned integer
394 Variable test: a character
396 =item C<first_name_str>
398 Variable first_name: a String class object
400 =item C<last_name_ch_a>
402 Variable last_name: a C<char> array
406 Variable foo: an C<Int*> that you must delete
410 Variable bar: an C<Int*> that you must not delete
414 Generally default arguments are taboo, except for nil pointers.
418 For some tasks, some scripts are supplied, notably creating patches, a
419 mirror of the website, generating the header to put over cc and hh
420 files, doing a release.