minetest_mana/API.md

API documentation for Mana 0.3.0
================================

**Warning:** This API is not considered stable yet.
Future releases will not enture backwards compability until the
release of version 1.0.0 of the Mana mod.


## Introduction
The API of the Mana mod allows you to set and receive
the current and maxiumum mana reserves of a player,
and to subtract and add mana.

## The basic rules
For integrity reasons, this mod will ensure that the following assumptions
are true at all times for all players:

* Current and maximum mana can never be smaller than 0
* The current value must not be greater than the maximum value

It should be not possible to break these rules using this API alone.
If you somehow manage to break one ofthe rules, please report a bug.

Furthermore, real numbers may be used as values, but it is not
recommended.

## Functions
Of not specified otherwise, all functions return `nil`.
`playername` always refers to the name of a player, as string.
`value` always refers to a number and for most functions it must always be equal to or greater than 0.


### `mana.set(playername, value)`
Sets the mana reserve of the specified player to `value`.
If `value` is smaller than 0, the mana will be set to 0.
If `value` is greater than the maximum, the mana will be set to the maximum.


### `mana.setmax(playername, value)`
Sets the maximum of the player to `value`.

If the new maximum would become smaller than the current value,
the current value will automatically be set to
the new maximum.


### `mana.get(playername)`
Returns the current mana of the specified player as number.


### `mana.getmax(playername)`
Returns the current maximum mana of the specified player as number.


### `mana.add(playername, value)`
Adds the specified non-negative amount of mana to the player, but only
if the sum would not be greater than the maximum,

#### Return value
* `true` on success, all mana has been added
* `false` on failure, no mana has been added


### `mana.subtract(playername, value)`
Subtracts the specified non-negative amount of mana from the player,
but only if the player has sufficient mana reservers.

#### Return value
* `true` on success, all mana has been subtracted
* `false` on failure, no mana has been subtraceed


### `mana.add_up_to(playername, value)`
Adds the specified non-negative amount of mana to the player, but it will
be capped at the maximum. 

#### Return value
* `true, excess` on success, where `excess` is the amount of Mana which could not be added because it would have exceeded the maximum. `excess` equals `0` if all mana has been added
* `false` on failure (mana could not be added)


### `mana.subtract_up_to(playername, value)`
Subtracts the specified non-negative amount of mana from the player, 
but if the difference is smaller than 0, the mana will be set to 0.

#### Return value
* `true, missing` on success, where `missing` is the amount of Mana which could not be subtracted because it would have exceeded 0. `missing` equals `0` if all mana has been subtracted 
* `false` on failure (mana could not be subtracted)