Re: Some remarks on PP docs
David B. Held:
It's hard enough getting one's head around the PP lib without having to be an expert in it already. [...] It's a shame, because there's a lot of code that would benefit from the PP lib that almost certainly isn't because of the difficult learning curve.
Learning Boost.Preprocessor is like learning a rather verbose and intricate programming language. It is not really surprising that it can be difficult to learn, although the documentation, at least the parts that I wrote, could certainly be improved. It is possible to implement a language using the C99 (or even the less capable C++97) preprocessor that would be much less verbose and intricate and would be significantly easier to use (see http://groups.yahoo.com/group/boost/files/Order/ for details), but it would come at some cost in efficiency (on some compilers the cost would probably be prohibitive and on some compilers the cost is insignificant). -Vesa Karvonen _________________________________________________________________ Protect your PC - get McAfee.com VirusScan Online http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
"Vesa Karvonen" <vesa_karvonen@hotmail.com> writes:
David B. Held:
It's hard enough getting one's head around the PP lib without having to be an expert in it already. [...] It's a shame, because there's a lot of code that would benefit from the PP lib that almost certainly isn't because of the difficult learning curve.
Learning Boost.Preprocessor is like learning a rather verbose and intricate programming language. It is not really surprising that it can be difficult to learn, although the documentation, at least the parts that I wrote, could certainly be improved.
When did he write that? Not in this thread. I'm writing an appendix on the PP lib for the MPL book today. I think that'll demonstrate that it's possible to provide a reasonable gentle and high-level introduction without exposing too many ugly details. The basic outline I'm following is below. If anyone would like to suggest changes, I'd be grateful. - Motivation - Example - Alternatives - Handcoded: error-prone - External Program Generated: not configurable - Fundamental PP Abstractions - Macros - Non function - Function macros - Tokens - Sequences of tokens not including un-parenthesized commas Note issues with commas and templates - How to read PP docs - BOOST_PP_ prefix - Header file convention - Z, R, D suffixes [We're not going to cover anything but automatic recursion in detail, but we need to explain these things so that people know how to ignore them in the PP docs ;->, and because their presence leaks into the macros they write for passing to higher-order PP lib macros] - PP library abstractions - Iteration - Horizontal: - Examples: BOOST_PP_ENUM_PARAMS... - Problems: Debuggability, Readability - Vertical - Local Iteration - File Iteration - Control structures - BOOST_PP_IF / BOOST_PP_IDENTITY / BOOST_PP_EMPTY - BOOST_PP_EXPR_IF - BOOST_PP_COMMA_IF - Data structures - sequences - tuples - arrays - lists
It is possible to implement a language using the C99 (or even the less capable C++97) preprocessor that would be much less verbose and intricate and would be significantly easier to use (see http://groups.yahoo.com/group/boost/files/Order/ for details), but it would come at some cost in efficiency (on some compilers the cost would probably be prohibitive and on some compilers the cost is insignificant).
Well, if you really have a conforming C99 preprocessor, you could use Paul M's Chaos, which I think is both easier to use and *way* more efficient than the current Boost PP. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com
David Abrahams <dave@boost-consulting.com> writes:
When did he write that? Not in this thread.
Oops, I missed it. Sorry to be such a doofus. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com
participants (2)
-
David Abrahams -
Vesa Karvonen