Globals

2022-09-09T20:03:58Z

Thacuber2a03: it's a map, "globals isa map" returns 1

'''globals''' is a built-in map that references [[variables]] at the global scope. Any assignment outside of any function creates (or updates) an entry in the '''globals''' map.

Inside a function, an unqualified assignment (i.e. an assignment to an identifier that does not follow a dot — like ''x'' rather than ''foo.x'') creates a local variable. Local variables exist only within the function where they are created, and disappear as soon as the function exits. This is true even if there happens to already be a global variable of the same name.

So, when you want to create or update a global variable inside a function, the '''globals''' map must be used on the left-hand side of the assignment.

See also: [[locals]]; [[outer]].

== Example ==
The ''check'' function below compares its parameter to a global variable. The comparison does not need the '''globals''' map, because it's only reading the value (and there is no local variable of the same name). But when it updates the global value, it has to use '''globals'''.

<ms>lastValue = null
check = function(someValue)
if someValue != lastValue then
print "The value is now: " + someValue
globals.lastValue = someValue // <--- Note use of globals
end if
end function

x = 0
while true
check round(x)
x = x + 0.1
wait 0.1
end while</ms>

Also note that the [[while]] loop at the end is at the global scope, so it does not need to use '''globals''' at all; globals and locals are the same in this case.

[[Category:Language]]
[[Category:Intrinsic Functions]]

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Globals