Multi-line arguments

When calling functions that take a large number of arguments, it is convenient to split the argument list over multiple lines. Because of the white-space sensitive nature of the language, care must be taken when splitting up the argument list.

If an argument list is to be continued onto the next line, the current line must end in a comma. And the following line must be indented more than the current indentation. Once indented, all other argument lines must be at the same level of indentation to be part of the argument list

my_func 5,4,3,
  8,9,10

cool_func 1,2,
  3,4,
  5,6,
  7,8

Lua:

my_func(5, 4, 3, 8, 9, 10)
cool_func(1, 2, 3, 4, 5, 6, 7, 8)

This type of invocation can be nested. The level of indentation is used to determine to which function the arguments belong to.

my_func 5,6,7,
  6, another_func 6,7,8,
    9,1,2,
  5,4

Lua:

my_func(5, 6, 7, 6, another_func(6, 7, 8, 9, 1, 2), 5, 4)

Because tables also use the comma as a delimiter, this indentation syntax is helpful for letting values be part of the argument list instead of being part of the table.

x = {
  1,2,3,4, a_func 4,5,
    5,6,
  8,9,10
}

Lua:

local x = {
  1,
  2,
  3,
  4,
  a_func(4, 5, 5, 6),
  8,
  9,
  10
}

Although uncommon, notice how we can give a deeper indentation for function arguments if we know we will be using a lower indentation further on.

y = { my_func 1,2,3,
   4,5,
  5,6,7
}

Lua:

local y = {
  my_func(1, 2, 3, 4, 5),
  5,
  6,
  7
}

The same thing can be done with other block level statements like conditionals. We can use indentation level to determine what statement a value belongs to:

MoonScript:

if func 1,2,3,
  "hello",
  "world"
    print "hello"
    print "I am inside if"

if func 1,2,3,
    "hello",
    "world"
  print "hello"
  print "I am inside if"

Lua:

if func(1, 2, 3, "hello", "world") then
  print("hello")
  print("I am inside if")
end
if func(1, 2, 3, "hello", "world") then
  print("hello")
  print("I am inside if")
end