differnce between ( ), { }, and [ ]

Solar2D General Questions/Discussion
#1

Simple question…

Can anyone explain the difference between ( ), { }, and [] when coding?

How to know which to use when?

#2

In short:

() – is for functions, for example: myFunction()

{} – is to for tables, for example: myTable = { itemOne, “Item two”, 57 }

[] – is to call objects from a table, for example myTable[3] would return 57

#3

Correct. One minor addition is that [] can be used not only to call, but also to set elements in a table, for example:

myTable[4] = “Janice”

would either change the 4th element in a table to the string “Janice”, or add it as a fourth element if there wasn’t one already.

#4

To add a little additional information…

Parenthesis () are used by functions, but they also are important for grouping items for math functions and in logic usage:

local a = 10 * 10 + 10

and

local a = 10 * (10 + 10)

are different results.  It’s useful in if and while statements too.

Lua allows functions that are expecting tables to be passed in to skip the parens:

local tv = widget.newSuperDuperView{param=1, param2=“fred”}

instead of doing:

local tv = widget.newSuperDuperView( {param=1, param2=“fred”} )

both are allowed.

#5

In short:

() – is for functions, for example: myFunction()

{} – is to for tables, for example: myTable = { itemOne, “Item two”, 57 }

[] – is to call objects from a table, for example myTable[3] would return 57

#6

Correct. One minor addition is that [] can be used not only to call, but also to set elements in a table, for example:

myTable[4] = “Janice”

would either change the 4th element in a table to the string “Janice”, or add it as a fourth element if there wasn’t one already.

#7

To add a little additional information…

Parenthesis () are used by functions, but they also are important for grouping items for math functions and in logic usage:

local a = 10 * 10 + 10

and

local a = 10 * (10 + 10)

are different results.  It’s useful in if and while statements too.

Lua allows functions that are expecting tables to be passed in to skip the parens:

local tv = widget.newSuperDuperView{param=1, param2=“fred”}

instead of doing:

local tv = widget.newSuperDuperView( {param=1, param2=“fred”} )

both are allowed.

#8

Thank you all. :wub:

#9

Thank you all. :wub: