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".
54 (add-hook 'c-mode-hook
55 '(lambda ()(setq c-basic-offset 4)))
58 (add-hook 'c++-mode-hook
59 '(lambda() (c-set-style "Stroustrup")
62 If you like using font-lock, you can also add this to your F<.emacs>:
64 (setq font-lock-maximum-decoration t)
65 (setq c++-font-lock-keywords-3
67 c++-font-lock-keywords-3
68 '(("\\b\\([a-zA-Z_]+_\\)\\b" 1 font-lock-variable-name-face)
69 ("\\b\\([A-Z]+[a-z_]+\\)\\b" 1 font-lock-type-face))
72 =head2 CLASSES and TYPES:
75 AClass_name (for Abbreviation_class_name)
80 Type Class::member_type_
82 the C<type> is a Hungarian notation postfix for C<Type>. See below
87 Broken code (hardwired dependencies, hardwired constants, slow
88 algorithms and obvious limitations) should be marked as such:
89 either with a verbose TODO, or with a short "ugh" comment.
93 The source is commented in the DOC++ style. Check out doc++ at
94 http://www.zib.de/Visual/software/doc++/index.html
97 C style comments for multiline comments.
98 They come before the thing to document.
105 Long class documentation.
108 TODO Fix boring_member()
120 short memo. long doco of member()
121 @param description of arguments
124 Rettype member(Argtype);
128 data_member_ = 121; // ugh
134 Unfortunately most of the code isn't really documented that good.
137 =head2 CLASSNAMES (2)
139 A lot of classes in GNU LilyPond start with 'P', this is to distinguish
140 certain parts of GNU LilyPond: the P stands for Printer, and the P-classes
141 are supposed to be more lowlevel than the others. Example:
143 Staff uses PStaff, PScore and PCol to do the typesetting of
144 symbols. Staff is the "brains" for PStaff
146 NB: in PCursor (which is part of the library) P stands for PointerCursor
153 ///check that *this satisfies its invariants, abort if not.
156 /// print *this (and substructures) to debugging log
160 protected member. Usually invoked by non-virtual XXXX()
164 /**add some data to *this.
165 Presence of these methods usually imply that it is not feasible to this
170 /// replace some data of *this
173 =head1 HUNGARIAN NOTATION NAMING CONVENTION
175 Proposed is a naming convention derived from the so-called I<Hungarian
180 The Hungarian Notation was conceived by or at least got its name from,
181 the hungarian programmer Charles Simonyi. It is a naming convention
182 with the aim to make code more readable (for fellow programmers), and
183 more accessible for programmers that are new to a project.
185 The essence of the Hungarian Notation is that every identifier has a
186 part which identifies its type (for functions this is the result
187 type). This is particularly useful in object oriented programming,
188 where a particular object implies a specific interface (a set of
189 member functions, perhaps some redefined operators), and for
190 accounting heap allocated memory pointers and links.
194 Another fun quote from Microsoft Secrets:
197 The Hungarian naming convention gives developers the ability
198 to read other people's code relatively easily, with a minmum
199 number of comments in the source code. Jon De Vann estimated
200 that only about 1 percent of all lines in the Excel product
201 code consist of comments, but the code is still very
202 understandable due to the use of Hungarian: "if you look at
203 our source code, you also notice very few comments. Hungarian
204 gives us the ability to go in and read code..."
207 Wow! If you use Hungarian you don't have to document your software!
208 Just think of the hours I have wasted documenting while this "silver bullet"
209 existed. I feel so stupid and ashamed!
217 more keystrokes (disk space!)
221 it looks silly C<get_slu_p()>
225 it looks like code from micro suckers
229 (which) might scare away some (otherwise good?)
230 progammers, or make you a paria in the free
239 not very useful if not used consistently
243 usefullness in I<very large> (but how many classes is very large?)
256 learn about cut and paste / use emacs or vi
257 or lean to type using ten fingers
261 Use emacs dabbrev-expand, with dabbrev-case-fold-search set to nil.
265 use no, or pick less silly, abbrvs.
269 use non-ambiguous postfixes C<identifier_name_type_modifier[_modifier]>
273 Macros, C<enum>s and C<const>s are all uppercase,
274 with the parts of the names separated by underscores.
283 unsigned char. (The postfix _by is ambiguous)
312 Zero terminated c string
320 =head2 User defined types
327 Slur* slur_p = new Slur;
331 The following types modify the meaning of the prefix.
332 These are precede the prefixes:
346 const. Note that the proper order C<Type const> i.s.o. C<const Type>
350 A const pointer. This would be equivalent to C<_c_l>, but since any
351 "const" pointer has to be a link (you can't delete a const pointer),
356 temporary pointer to object (link)
360 pointer to newed object
372 Variable loop: an integer
376 Temporary variable: an unsigned integer
380 Variable test: a character
382 =item C<first_name_str>
384 Variable first_name: a String class object
386 =item C<last_name_ch_a>
388 Variable last_name: a C<char> array
392 Variable foo: an C<Int*> that you must delete
396 Variable bar: an C<Int*> that you must not delete
400 Generally default arguments are taboo, except for nil pointers.