5.3 version of mathx (Was: [ANN] Lua 5.3.0 (work3) now available

[Dirk Laurie <dirk.laurie@...>]

General comment: with the disappearance of cosh, sinh, tanh from Lua itself,
considerations come into play that were not pressing for the 5.2
version of mathx.
People with programs that used those would hope that putting

    if not math.cosh then require 'mathx' end

would retain compatibility. That would make it helpful for `mathx` be mentioned
in the Lua 5.3 manual as an example of a suitable external library.  But not if
`mathx` while providing the missing functions introduces new incompatinilities.

It used to be simple: `math` is C89, `mathx` is C99, and one could merely
refer to the respective C documentation. But Lua has gradually moved away
from blindly following C89, at least where the math library is concerned, and
the `mathx` module with its README sentence:

---
There is no manual: see the summary below and a C99 reference manual, e.g.
        http://en.wikipedia.org/wiki/C_mathematical_functions
---

might slot in better with Lua 5.3 if it could say instead:

---
There is no manual: see, in this order, the Lua 5.3 manual, the summary below
and a C99 reference manual, e.g.
        http://en.wikipedia.org/wiki/C_mathematical_functions
---

Trivial but annoying detail: with gcc 4.8.2 (Ubuntu 4.8.2-19ubuntu1) for
x86_64-linux-gnu, the compiler tells me to add -fPIC to the compiler flags.
Then it works.

2014-06-20 15:39 GMT+02:00 Luiz Henrique de Figueiredo <lhf@tecgraf.puc-rio.br>:

> Perhaps these changes should be done as well:
>         atan2 -> atan (as in Lua 5.3)
>         fmin -> min
>         fmax -> max
>         log -> accept an optional base
>
> Finally, like previous versions of mathx, this one adds functions the
> existing math library, overwriting the functions already there. This
> is a problem for abs (which works with integers as well) and log (which
> accepts an optional base; this one is easy to fix).

As discussed above, requirements should be drop-in. At the very least,
extra arguments should be errors. Quietly discarding them is confusing.

$ lua53
Lua 5.3.0 (work3)  Copyright (C) 1994-2014 Lua.org, PUC-Rio

> math.abs(-2)
2
> math.log(1024,2)
10.0
> return math.atan(49,49)/math.pi
0.25

> require"mathx"
table: 0x1e3d960

> return math.abs(-2)
2.0
> return math.log(1024,2)
6.9314718055995
> return math.atan(49,49)/math.pi
0.49350478151163

Note that Lua 5.3 now does this:

> math.min('a','b','c')
a

While I like that, it argues strongly against renaming fmin and fmax.