Fun with operators, numeric units, and application in Kopi

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Mike Austin

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Nov 14, 2021, 5:20:42 PM11/14/21
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I have to say, function application via juxtaposition (whitespace like Haskell) provides many opportunities to customize the language, almost to the point of a DSL.

print (4 ft + 6 in)
print (4 ft + 12.7 cm)

Number apply simply calls the argument with itself. Bam! Numeric units. String/Sequence apply calls concat.

Imperial = type (value: Int)

extend Imperial (
toImperial: (this) => () => this
+: (this) => (that) => Imperial (value: this.value + (that | toImperial).value)
)

ft (n) = Imperial (value: n)
in (n) = Imperial (value: n / 12)

print (4 ft + 6 in)


# Add Metric unit

Metric = type (value: Int)

m (n) = Metric (value: n)
cm (n) = Metric (value: n / 10)

extend Imperial (
toMetric: (this) => () => Metric (value: this.value * 2.54)
)

extend Metric (
toMetric: (this) => () => this
toImperial: (this) => () => Imperial (value: this.value / 2.54)
+: (this) => (that) => Imperial (value: this.value + (that | toMetric).value)
)

print (4 ft + 12.7 cm)

Raoul Duke

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Nov 14, 2021, 5:44:53 PM11/14/21
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i do believe that is what the haskell people have been saying for quite a while, agreed. 

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