dottis, `.=`, %dtts

Equality

.= is a natural rune that applies Nock 5 (equality) to determine if the products of p and q are equivalent, and produces a loobean.

Produces

Twig: [%dtts p=twig q=twig]

Sample

p is a twig. q is a twig.

Tall form

.=  p
    q

Wide form

.=(p q)

Irregular form

=(p q)

Examples

~zod/try=> =(0 0)
%.y
~zod/try=> =(1 2)
%.n

Comparing two atoms is the most straightforward case of .=.

~zod/try=> =("a" [97 ~])
%.y
~zod/try=> =(~nec 1)
%.y
~zod/try=> =([%a 2] a/(dec 3))
%.y
~zod/try=> =([%b 2] a/(dec 3))
%.n

It's important to keep in mind that .= compares the atomic equivalent of each p and q. In the first case of this example the tape "a" is actually the list [97 0] since the ASCII code for 'a' is 97. The following cases serve to show similar implicit down-casts.

/~zod/try=> =isa  |=  a=@t
                  ?:  =(a 'a')
                    'yes a'
                  'not a'
new var %isa
/~zod/try=> (isa 'b')
'not a'
/~zod/try=> (isa 'a')
'yes a'

In common practice .= is often used inside of ? runes, where switching on equality is needed. Here we construct a simple gate to test if our sample is equal to 'a' and produce either 'yes a' or 'not a' accordingly.

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dottis, .=, %dtts

See also