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David Jones wrote:
On Mar 31, 2006, at 07:15, Lisa Parratt wrote:On 30 Mar 2006, at 23:46, Luiz Henrique de Figueiredo wrote:Also, the Lua core depends lightly on the ANSI C runtime library. Besides some simple functions from string.h and ctype.h, it needs sprintf and strtod to convert doubles to and from text, and setjmp, longjmp and exit. Lua 5.1 also needs pow, floor, and localeconv. The Lua libraries depend more heavily on the C standard library.I don't see this as an advantage. The first thing I have to do with a new Lua release is patch in an abstraction layer so that these may be easily replaced. Personally I'd like to see every "standard" function call given a prefix and a default header file of #defines that maps them to their nonprefixed equivalents.Why can't you just provide replacements for the C standard library facilities that have the same names as the functions from the C standard library?
Because the functions are provided by the C library, they're just buggy/incomplete/inadequate for purposes/incompatible with configuration. In the real world, projects are written by multiple people. I can't wholesale replace standard functions, despite their flaws - other people may and probably will have written code that depends on those flaws. Yes I could raise I bug on them, but when the product's late already it makes it look like my problem, and therefore as far as the company's concerned - *Lua*s problem.
"pow" is in fact an example of where Lua does it *right* - it doesn't call "pow", it calls "luai_numpow". The platforms I regularly work on have no floating point, and emulate it if you try and use math functions. Lua is configured to use integers. I obviously don't want to be calling "pow", so a quick modification to the configuration, and it now calls "intPow". This uses integer partial products to perform the exponentiation, and gives me far better performance.
I'm not saying Lua should be rendered difficult to integrate. It's just it should be made fully independent, but provided with default bindings that are useful in the most common case, exactly as is the case with luai_numpow.
-- Lisa