Good coding-style, a talk made in 2008 to encourage changes in MySQL coding style
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This document discusses the importance of having a consistent and up-to-date coding style at MySQL. It notes problems with the current style, such as obsolete conventions like using TRUE/FALSE instead of true/false, as well as inconsistencies in the style being applied. The document proposes some initial steps to improve the style, and addresses common criticisms of changing the style, suggesting that improvements be made carefully. It concludes by providing references to coding style guides as examples.
Good coding-style, a talk made in 2008 to encourage changes in MySQL coding style
- 1. Good coding style A drama in 12 parts with an epilogue Konstantin Osipov Staff Engineer Sun/MySQL [email protected] These slides released under the Creative Commons AttributionNoncommercialShare Alike License
- 2. Agenda ● It's all Monty's fault! Or maybe not? ● Define the problem ● What can be done ● Call to arms ● Thank you & References
- 3. What's a good coding style? ● C++ FAQ Lite: Thank you for reading this answer rather than just trying to set your own coding standards. But beware that some people on comp.lang.c++ are very sensitive on this issue. Nearly every software engineer has, at some point, been exploited by someone who used coding standards as a "power play." Furthermore some attempts to set C++ coding standards have been made by those who didn't know what they were talking about, so the standards end up being based on what was the state-of-the-art when the standards setters were writing code. Such impositions generate an attitude of mistrust for coding standards.
- 4. Why is it a problem: the style is obsolete kostja@bodhi:~/work/mysql-6.0-runtime/sql$ grep '<true>' *.{h,cc} | grep -v sql_yacc.cc | wc -l 356356 kostja@bodhi:~/work/mysql-6.0-runtime/sql$ grep '<false>' *. {h,cc} | grep -v sql_yacc.cc | wc -l 212
- 5. Why is it a problem: the style is ignored struct st_bstream_snapshot_info class QUICK_RANGE class DsMrr_impl class MDL_context and class DDL_blocker_class typedef struct st_table_ref TABLE_REF class NdbScanOperation and class TableEvent class sp_head and sp_instr_jump
- 6. Why is it a problem: maintenance Foo::Foo(int a_arg, int b_arg, int c_arg) : a(a_arg), b(b_arg), c(c_arg) -> rename or add a member int descriptive_identifier_name1= 1; char not_so_descriptive= 2; -> now add a declaration of very_long_and_descriptive_identifier3 My_long_class_name::My_long_class_name(int param1, Type1 param 2, Type2 param3); -> rename the class or the method
- 7. Why is It a problem: practice ● sheer neglect to copy constructors and assignment operators ● all members are public, in new code as well ● -> C++ practice guide is missing
- 8. Define a good coding style, attempt #2 ● helps readability ● prevents coding mistakes ● simplifies maintenance ● easy to learn ● unambiguous ● comes with a best practices guide
- 9. A change is called for! Possible immediate steps: ● prefer new/delete to malloc()/free() wherever possible ● TRUE -> true, FALSE -> false switch ● m_ prefixes for private class members ● remove typedef st_name {} NAME constructs ● your pet peeve can be here, if it's also everybody's
- 10. The criticism ● what we have is good enough, and everybody is used to it ● there are more important problems (AKA re- engineering is our savior) ● a change means the code is always half-way through it. Doxygen comments adoption. ● changes in the style is a revision history noise
- 11. What can be done? ● let's talk about it, but not too much ● accept and follow the current status quo ● improve what we have, with care
- 12. Thank you!
- 13. References ● MySQL coding guidelines : http://forge.mysql.com/wiki/MySQL_Internals_Coding_Guidelines ● C++ FAQ lite: http://www.parashift.com/c++-faq-lite/ ● Bjarne Stroustrup's FAQ: http://www.research.att.com/~bs/bs_faq.html ● C++ Style Guide from Geosoft.no: http://geosoft.no/development/cppstyle.html ● Collection of other styles: http://www.chris-lott.org/resources/cstyle/