X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=docs%2Fcoding-style.html;h=8fbb27688cc975c3823ed19517201e9f299a7a72;hp=250ab88c3d91bc73dd888876a269367208c17e8b;hb=a385f0af5ea320a18d580f6a36c59c55b3516efd;hpb=d31d3e069e7f0811a17942414e5eb4f28c04bf5e diff --git a/docs/coding-style.html b/docs/coding-style.html index 250ab88..8fbb276 100644 --- a/docs/coding-style.html +++ b/docs/coding-style.html @@ -1,11 +1,12 @@ - GHC Style Guidelines for C code + + Style Guidelines for fptools -

GHC Style guidelines for C code

Style Guidelines for fptools

Comments

@@ -57,12 +58,12 @@ Hill C Style and Coding Standards.

Portability issues

We try to stick to C99 where possible. We use the following +
We try to stick to C99 where possible. We use the following C99 features relative to C89, some of which were previously GCC extensions (possibly with different syntax):
- Variable length arrays as the last field of a struct. GCC has +
- Variable length arrays as the last field of a struct. GCC has a similar extension, but the syntax is slightly different: in GCC you would declare the array as arr[0], whereas in C99 it is declared as arr[]. @@ -90,9 +91,9 @@ header file). #ifdef __GNUC__:
  - Function attributes (mostly just no_return and +
  - Function attributes (mostly just no_return and unused) -
  - Inline assembly. +
  - Inline assembly.
- @@ -164,7 +165,7 @@ Avoid conditional code like this: #endif -Instead, add an appropriate test to the configure.in script and use +Instead, add an appropriate test to the configure.ac script and use the result of that test instead.
```
@@ -223,24 +224,24 @@ code is removed altogether if DEBUG is not defined).
 Particular guidelines for writing robust code:
 
 
-

+

 Use assertions.  Use lots of assertions.  If you write a comment
 that says "takes a +ve number" add an assertion.  If you're casting
 an int to a nat, add an assertion.  If you're casting an int to a char,
 add an assertion.  We use the ASSERT macro for writing
 assertions; it goes away when DEBUG is not defined.
 
-

+

 Write special debugging code to check the integrity of your data structures.
 (Most of the runtime checking code is in rts/Sanity.c)
 Add extra assertions which call this code at the start and end of any
 code that operates on your data structures.
 
-

+

 When you find a hard-to-spot bug, try to think of some assertions,
 sanity checks or whatever that would have made the bug easier to find.
 
-

+

 When defining an enumeration, it's a good idea not to use 0 for normal
 values.  Instead, make 0 raise an internal error.  The idea here is to
 make it easier to detect pointer-related errors on the assumption that
@@ -268,7 +269,7 @@ piece of incomplete/broken code.
 Syntactic details
 
 
-
Important: Put "redundant" braces or parens in your code.
+
Important: Put "redundant" braces or parens in your code.
 Omitting braces and parens leads to very hard to spot bugs -
 especially if you use macros (and you might have noticed that GHC does
 this a lot!)
@@ -276,13 +277,13 @@ this a lot!)
 
 In particular:
 

-

+

 Put braces round the body of for loops, while loops, if statements, etc.
 even if they "aren't needed" because it's really hard to find the resulting
 bug if you mess up.  Indent them any way you like but put them in there!
 
 
-

+

 When defining a macro, always put parens round args - just in case.
 For example, write:
 @@ -293,25 +294,25 @@ instead of
   #define add(x,y) x+y
 
 
-
 Don't declare and initialize variables at the same time.
+
 Don't declare and initialize variables at the same time.
 Separating the declaration and initialization takes more lines, but
 make the code clearer.
 
-

+

 Use inline functions instead of macros if possible - they're a lot
 less tricky to get right and don't suffer from the usual problems
 of side effects, evaluation order, multiple evaluation, etc.
 
 
-
Inline functions get the naming issue right.  E.g. they
+
Inline functions get the naming issue right.  E.g. they
   can have local variables which (in an expression context)
   macros can't.
 
-
 Inline functions have call-by-value semantics whereas macros
+
 Inline functions have call-by-value semantics whereas macros
   are call-by-name.  You can be bitten by duplicated computation
   if you aren't careful.
 
-
 You can use inline functions from inside gdb if you compile with
+
 You can use inline functions from inside gdb if you compile with
   -O0 or -fkeep-inline-functions.  If you use macros, you'd better
   know what they expand to.
 
@@ -327,13 +328,13 @@ can be "polymorphic" as these examples show:
   #define min(x,y) (((x)<=(y)) ? (x) : (y))
 
```
  -
- +
- Inline functions should be "static inline" because:
  - +
  - gcc will delete static inlines if not used or theyre always inlined. -
  - +
  - if they're externed, we could get conflicts between 2 copies of the same function if, for some reason, gcc is unable to delete them. If they're static, we still get multiple copies but at least they don't conflict. @@ -397,9 +398,8 @@ up as well. Use the doNothing macro instead.
```
   #define doNothing() do { } while (0)
 
```
    -
  -
- +
- This code
```
 int* p, q;
@@ -416,7 +416,7 @@ int *p, *q;
 
```
  but it is preferrable to split the declarations. -
- +
- Try to use ANSI C's enum feature when defining lists of constants of the same type. Among other benefits, you'll notice that gdb uses the name instead of its (usually inscrutable) number when printing values @@ -467,16 +467,16 @@ instead of # define TIMEchar 'T' -
- Please keep to 80 columns: the line has to be drawn somewhere, +
- Please keep to 80 columns: the line has to be drawn somewhere, and by keeping it to 80 columns we can ensure that code looks OK on everyone's screen. Long lines are hard to read, and a sign that the code needs to be restructured anyway. -
- When commenting out large chunks of code, use #ifdef 0 +
- When commenting out large chunks of code, use #ifdef 0 ... #endif rather than /* ... */ because C doesn't have nested comments. -
- When declaring a typedef for a struct, give the struct a name +
- When declaring a typedef for a struct, give the struct a name as well, so that other headers can forward-reference the struct name and it becomes possible to have opaque pointers to the struct. Our convention is to name the struct the same as the typedef, but add a @@ -488,10 +488,10 @@ leading underscore. For example: } Foo; -
- Do not use ! instead of explicit comparison against +
- Do not use ! instead of explicit comparison against NULL or '\0'; the latter is much clearer. -
- We don't care too much about your indentation style but, if +
- We don't care too much about your indentation style but, if you're modifying a function, please try to use the same style as the rest of the function (or file). If you're writing new code, a tab width of 4 is preferred. @@ -501,7 +501,7 @@ tab width of 4 is preferred. CVS issues - + Don't be tempted to reindent or reorganise large chunks of code - it generates large diffs in which it's hard to see whether anything else was changed. @@ -512,5 +512,31 @@ it in case anyone else is changing that file. +Commandline arguments + +A program in fptools should try follow the following rules for +commandline arguments: + + + The -v and --verbose options should be +used to generate verbose output (intended for the user). + + The -d and --debug options should be +used to generate debugging output (intended for the developer). + + The -? and --help options should be used +to display usage information on stdout. The program should exit +successfully afterwards. + + The -V and --version options should be +used to output version information on stdout, which includes one line +of the form 'Program version +Major.Minor[.Patchlevel] ... '. The program +should exit successfully afterwards. + + +When an unknown commandline argument is encountered, the program +should display usage information on stderr and exit unsuccessfully. +

GHC Style guidelines for C code

Style Guidelines for fptools

Comments

Portability issues

Syntactic details

CVS issues

Commandline arguments