History of the Lua math library

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

Since the HISTORY file supplied with Lua distributions up to Lua 5.1.5
does not include details about the math library, I have compiled the
included file (in Markdown text). There are probably some errors and
omissions.

A History of the Lua Mathematics Library
========================================

Lua 1.0
-------

The mathematical library is in the file `mathlib.c` written
by Waldemar Celes Filho and dated 19 May 93. It contains the
following functions:

    abs acos asin atan ceil cos floor max min
    mod pow sin sqrt tan

In the case of the trigonometric functions, all angles are in 
radians.

Lua 1.1
-------

The mathematical library is in the file `clients/lib/mathlib.c`
and the RCS author tag contains `1993/12/17 18:41:19 celes`.
 
The same functions as in Lua 1.0 are provided, but the angles
are now in degrees.

Lua 2.1
-------

The mathematical library is in the file `clients/lib/mathlib.c`
and the RCS author tag contains `1995/02/06 19:36:43 roberto`.
 
To the functions provided in Lua 1.1 have been added:

    deg exp log log10 rad

`deg`, `exp` and `rad` are not listed in the manual.

The `pow` function is no longer available under that name,
but is the fallback function for the new exponentiation operator.

Lua 2.2
-------

The mathematical library is in the file `clients/lib/mathlib.c`
and the RCS author tag contains `1995/11/10 17:54:31 roberto`.

To the functions provided in Lua 2.1 have been added:

    atan2

`deg`, `exp` and `rad` are not listed in the manual.

Lua 2.4
-------

The mathematical library is in the file `clients/lib/mathlib.c`
and the RCS author tag contains `1996/04/30 21:13:55 roberto`.

To the functions provided in Lua 2.1 have been added:

    random randomseed

`deg`, `exp` and `rad` are not listed in the manual.

Lua 2.5
-------

The mathematical library is in the file `clients/lib/mathlib.c`
and the RCS author tag contains `1996/08/01 14:55:33 roberto`.

The only change is that the `mod` function accepts floats and
calculates `fmod(x,y)` instead of `x%y`.

`deg`, `exp` and `rad` are not listed in the manual.

Lua 3.0
-------

The mathematical library is in the file `clients/lib/mathlib.c`
and the RCS author tag contains `1997/06/19 18:03:04 roberto`.

`deg`, `exp` and `rad` are not listed in the manual.

The same functions as in Lua 2.5 are provided.

Lua 3.1
-------

The mathematical library is in the file `src/lib/lmathlib.c`
and the RCS author tag contains `1997/06/19 18:03:04 roberto`.

To the functions provided in Lua 3.0 have been added:

    frexp ldexp

All the functions are listed in the manual.

This was the release at which the defalt number format was
changed to double.

There is a hint of the coming change from radians to degrees
in a global variable `_TRIGMODE` with initial value "deg".
However, changing this variable has no effect.

Lua 3.2
-------

The mathematical library is in the file `src/lib/lmathlib.c`
and the RCS author tag contains `1999/07/07 17:54:08 roberto`.

The same functions as in Lua 3.1 are provided.

`_TRIGMODE` is gone. However, a compiler variable `RADIANS`
allows you to build a Lua in which angles are in radians.

Lua 4.0
-------

The mathematical library is in the file `src/lib/lmathlib.c`
and the RCS author tag contains `2000/10/31 13:10:24 roberto`.

The same functions as in Lua 3.1 are provided.

In addition, `PI` is provided as a global variable.

Lua 5.0
-------

The mathematical library is in the file `src/lib/lmathlib.c`
and the RCS author tag contains `2003/03/11 12:30:37 roberto`.

At the Lua level, the functions are no longer directly in the
global namespace but are delivered in the table `math`.

To the functions provided in Lua 4.0 have been added:

    pow

In the case of the trigonometric functions, all angles are in 
radians. The compiler variable `USE_DEGREES` allows you to 
build a Lua in which angles are in degrees.

The global variable `PI` has been renamed `math.pi`.

Lua 5.1
-------

The mathematical library is in the file `src/lmathlib.c`
and the RCS author tag contains `2007/12/27 13:02:25 roberto`.

The function `mod` has two aliases: `fmod` and `modf`.

To the functions provided in Lua 5.0 have been added:

    cosh sinh tanh

There is a new predefined value `math.huge`.

Lua 5.2
-------

The mathematical library is in the file `src/lmathlib.c`
and the RCS author tag contains `2013/04/12 18:48:47 roberto`.

The value of PI is given in the source code to 31 decimal places.

The same functions as in Lua 5.1 are provided, but `log` now
takes an optional second argument and `log10` has been deprecated.