Difference between revisions of "RefEquals"
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(Created page with "The <c>refEquals</c> function checks two values for reference equality. This is different from the <c>==</c> operator, which checks whether two values are ''equivalent'' (e.g...") |
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Whenever <c>refEquals(a, b)</c> is true (1), then you know that any modification of <c>a</c> will also be seen via <c>b</c>, because <c>a</c> and <c>b</c> refer to the same object. | Whenever <c>refEquals(a, b)</c> is true (1), then you know that any modification of <c>a</c> will also be seen via <c>b</c>, because <c>a</c> and <c>b</c> refer to the same object. | ||
| + | |||
| + | For immutable types – <c>null</c>s, <c>number</c>s and <c>string</c>'s – <c>refEquals</c> returns the same result as the <c>==</c> operator. | ||
=== Arguments === | === Arguments === | ||
| Line 24: | Line 26: | ||
print refEquals(a,b) // prints 1, as these are the same map | print refEquals(a,b) // prints 1, as these are the same map | ||
print refEquals(a,c) // prints 0, as these are different maps | print refEquals(a,c) // prints 0, as these are different maps | ||
| + | |||
| + | print refEquals(42,42)// prints 1 | ||
| + | nan = 0/0 | ||
| + | print refEquals(nan,nan)//prints 0 | ||
</ms> | </ms> | ||
[[Category:Intrinsic Functions]] | [[Category:Intrinsic Functions]] | ||
[[Category:Numeric Functions]] | [[Category:Numeric Functions]] | ||
Latest revision as of 08:13, 17 November 2023
The refEquals function checks two values for reference equality. This is different from the == operator, which checks whether two values are equivalent (e.g., two maps that contain equal key/value pairs, or two lists which contain equal values).
Whenever refEquals(a, b) is true (1), then you know that any modification of a will also be seen via b, because a and b refer to the same object.
For immutable types – nulls, numbers and string's – refEquals returns the same result as the == operator.
Arguments
| Parameter Name | Default Value | Meaning |
|---|---|---|
| a | any value | first argument |
| b | any value | second argument |
Example
a = {"foo":42}
b = a
c = {"foo":42}
print a == b // prints 1, because a and b have the same value
print a == c // prints 1, because a and c have the same value
print refEquals(a,b) // prints 1, as these are the same map
print refEquals(a,c) // prints 0, as these are different maps
print refEquals(42,42)// prints 1
nan = 0/0
print refEquals(nan,nan)//prints 0
