esi-tool
This library contains various helper functions of different type, not really matching one of the major topics.
Changes
| Version | Date | Description | s:i Release |
|---|---|---|---|
1.0.1 |
2018-06-24 |
added FILETOTABLE |
1.36 |
1.0.0 |
2018-06-03 |
First system:inmation inclusion |
1.34 |
0.1.5 |
2018-06-03 |
extended NUMBERTYPE for a range checking option |
|
0.1.4 |
2018-05-29 |
type checks added |
|
0.1.1 |
2018-05-27 |
Initial release |
Available functions
The library supplies the following public functions:
BOOLEANTYPE a simple check for Lua data type boolean
FUNCTIONTYPE a simple check for Lua data type function
IIF an immediate if, missing in Lua
INFO to comply with the ESI standard
ISOBJECT a simple check for valid inmation objects as parameters
NILTYPE a simple check for Lua data type nil
NUMBERTYPE a check for Lua data type number, optionally a range
RELTIME translates a relative time mask in a millisecond posix time
STRINGTYPE a simple check for Lua data type string
TABLETYPE a simple check for Lua data type table
THREADTYPE a simple check for Lua data type thread
USERDATATYPE a simple check for Lua data type userdata
Documentation
The library functions are documented in detail in the following sections.
IIF(condition,trueret,falseret)
Tests a condition and returns one of two results depending on the evaluation result.
Note: In principle, all three parameters are optional, but unless at least condition and trueret are something
different than nil, the function can return itself something different than nil.
IIF parameters
condition (variant, optional)
Anything might be passed into the function as condition, but it will only return the trueret parameter in case the
condition evaluates to true.
RELTIME(mask,from)
Calculates relative time from either current component time or a given time reference. The relative distance is expressed by a string, which can be composed of day(s), hour(s), minute(s) and second(s).
RELTIME parameters
mask (string, required)
A string like "-1d" or "-1d" or "1d", all equivalent. The leading -sign is always assumed and refers to now - or in
case the from parameter is given - to the point in time which the from parameter holds. The plus or minus sign can be
omitted, if it is ommitted a minus is the default. As such, the +-sign needs to be specified for the calculation of
future points in time.
| Mask element (Token) | Valid expressions |
|---|---|
Days |
"d","D","days","day" |
Hours |
"h","H","hours","hour" |
Minutes |
"m","M","minutes","minute","mins","min" |
Seconds |
"s","S","seconds","second","secs","sec" |
The parsing happens case-insensitive, so all equivalent uppercase tokens would work as well.
from (string or number, optional)
In case from is supplied as a string, it must be supplied as ISO8601
compliant UTC time string, such as "2018-02-23T17:50:23.000Z".
In case from is supplied as a number, it will be interpreted as milliseconds since EPOCH UTC, also known as POSIX
time. This is the internal inmation standard time.
RELTIME returns
the calculated POSIX time as a number (It can easily transformed in its string equivalent by using
inmation.gettime()), or nil in case of an invalid mask.
RELTIME Usage
local ts=TOOL:RELTIME("*-1d 6h 40m")
assert(ts)
return inmation.gettime(ts)or (using a weird mask)
local ts=TOOL:RELTIME("1 dAy 6 HourS 40 mINs")
assert(ts)
return inmation.gettime(ts)or (with given reference time)
local ts=TOOL:RELTIME("1D6H40M","2018-01-01T12:00:00.000Z")
assert(ts)
return inmation.gettime(ts)NUMBERTYPE(n,rangelo,rangehi)
Tests n to be a Lua data type number. It can optionally check for a range.
CHECKTYPE(somevariable, expectedtype, throwlevel)
Returns a read-only version of the table passed
MEMOIZE(func)
Returns a memoized (caching) version of the function passed.
MEMOIZE Usage
local TOOL = require('esi-tool')
function triangle(x)
if x == 0 then
return 0
end
return x+triangle(x-1)
end
--print(triangle(40000)) -- stack overflow: too much recursion
triangle = TOOL:MEMOIZE(triangle) -- make triangle function memoized, so it "remembers" previous results
-- seed triangle's cache
for i=0, 40000 do
triangle(i)
end
print(triangle(40000)) -- 800020000, instantaneous resultAUTOMAGICTABLE()
Returns a table whose fields are initialized on access (no "attempt to index a nil value" error)