# Standard Library

| Status | Last Update | API Version |
| ------ | ------ | ------ |
| Active | 2019-11-16 | V1.00.00 |

## Description
The meter supports tailored lua standard library, this lists tailor conditions.
Notice that the support conditions could change for further firmware releases.
Except for very critical development problems, the supported library would only expand, but it is not guaranteed.

## Additional Information
The standard lua library didn't provide a way to create a directory, this is provided by `sys.mkdir()` function.

## OverView
The following gives you a rough view of the tailor conditions:

| Library | Condition |
| ------ | ------ | 
| os | Partially Tailored |
| string | Available |
| io | Partially Tailored |
| package | Partially Tailored |  |
| table | Available |  |
| math | Partially Tailored |  |
| debug | Partially Tailored |  |
| coroutine | Available |  |

## os

| Function | Condition | Additional Information |
| ------ | ------ | ------ |
| clock() | Available | This returns the milisecond count since startup on this platform |
| date() | Available | |
| difftime() | Use carefully | *Note1 |
| execute() | Tailored | No use on such platform |
| exit() | Available |  |
| getenv() | Tailored | No use on such platform |
| remove() | Available | This is able to remove a directory or a file on this platform |
| rename() | Available |  This is able to remove a directory or a file on this platform |
| setlocale() | Available |  |
| time() |  Use carefully | *Note1 |
| tmpname() | Tailored ||

Notes:
1. To minimize RAM usage, on this platform we use single precision float as the lua number type, the valid precision of float is lower than uint32. Due to this reason, the return values from difftime(), time(), which actually uses POSIX timestamp, lose quite a lot of resolution. The return value is in a resolution of 128 seconds instead of 1 second. It's recommended to use os.date() to prevent POSIX return value.

## string

| Function | Condition | Additional Information |
| ------ | ------ | ------ |
| byte() | Available |  |
| char() | Available | |
| dump() | Available ||
| find() | Available |  |
| format() | Available |  |
| gfind() | Available |  |
| gmatch() | Available |  |
| gsub() | Available |  |
| len() | Available |  |
| lower() | Available | |
| rep() | Available | |
| reverse() | Available | |
| sub() | Available | |
| upper() | Available | |

## io

| Function | Condition | Additional Information |
| ------ | ------ | ------ |
| close() | Available |  |
| flush() | Available |  |
| input() | Available |  |
| lines() | Available |  |
| open() | Available |  |
| output() | Available |  |
| popen() | Tailored | No use on such platform  |
| read() | Available |  |
| type() | Available |  |
| write() | Available |  |
| file:close() | Available |  |
| file:flush() | Available |  |
| file:lines() | Available |  |
| file:read() | Available |  |
| file:seek() | Available |  |
| file:setvbuf() | Tailored | No use on such platform |
| file:write() | Available |  |
The file access is redirected to the internal storage.

## package

| Function | Condition | Additional Information |
| ------ | ------ | ------ |
| loadlib() | Tailored |  |
| seeall() | Available |  |

## table

| Function | Condition | Additional Information |
| ------ | ------ | ------ |
| concat() | Available |  |
| insert() | Available |  |
| move() | Available |  |
| pack() | Available |  |
| remove() | Available |  |
| sort() | Available |  |
| unpack() | Available |  |

## math

| Function | Condition | Additional Information |
| ------ | ------ | ------ |
| abs() | Available |  |
| acos() | Tailored | *Note1 |
| asin() | Tailored | *Note1 |
| atan() | Tailored | *Note1 |
| ceil() | Available |  |
| cosh() | Tailored | *Note1 |
| cos() | Tailored | *Note1 |
| deg() | Tailored | *Note1 |
| exp() | Tailored | *Note1 |
| floor() | Available |  |
| fmod() | Available |  |
| mod() | Available |  |
| frexp() | Tailored | *Note1 |
| ldexp() | Tailored | *Note1 |
| log10() | Tailored | *Note1 |
| log() | Tailored | *Note1 |
| max() | Available |  |
| min() | Available |  |
| modf() | Available |  |
| pow() | Available |  |
| rad() | Tailored | *Note1 |
| random() | Available |  |
| randomseed() | Available |  |
| sinh() | Tailored | *Note1 |
| sin() | Tailored | *Note1 |
| sqrt() | Available |  |
| tanh() | Tailored | *Note1 |
| tan() | Tailored | *Note1 |
Notes:
1. Trig, log, and exp functions are tailored as they are rarely used on applications of this meter, and they come with a large footprint.

## debug

| Function | Condition | Additional Information |
| ------ | ------ | ------ |
| debug() | Tailored | No such interactive interface available  |
| gethook() | Available |  |
| getinfo() | Available |  |
| getlocal() | Available |  |
| getmetatable() | Available |  |
| getregistry() | Available |  |
| getupvalue() | Available |  |
| getuservalue() | Available |  |
| sethook() | Available |  |
| setlocal() | Available |  |
| setmetatable() | Available |  |
| setupvalue() | Available |  |
| setuservalue() | Available |  |
| traceback() | Available |  |

## coroutine
	
| Function | Condition | Additional Information |
| ------ | ------ | ------ |
| create() | Available |  |
| resume() | Available |  |
| running() | Available |  |
| status() | Available |  |
| wrap() | Available |  |
| yield() | Available |  |