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discard """
file: "tcurrncy.nim"
output: "25"
"""
template Additive(typ: untyped) =
proc `+` *(x, y: typ): typ {.borrow.}
proc `-` *(x, y: typ): typ {.borrow.}
# unary operators:
proc `+` *(x: typ): typ {.borrow.}
proc `-` *(x: typ): typ {.borrow.}
template Multiplicative(typ, base: untyped) =
proc `*` *(x: typ, y: base): typ {.borrow.}
proc `*` *(x: base, y: typ): typ {.borrow.}
proc `div` *(x: typ, y: base): typ {.borrow.}
proc `mod` *(x: typ, y: base): typ {.borrow.}
template Comparable(typ: untyped) =
proc `<` * (x, y: typ): bool {.borrow.}
proc `<=` * (x, y: typ): bool {.borrow.}
proc `==` * (x, y: typ): bool {.borrow.}
template DefineCurrency(typ, base: untyped) =
type
typ* = distinct base
Additive(typ)
Multiplicative(typ, base)
Comparable(typ)
proc `$` * (t: typ): string {.borrow.}
DefineCurrency(TDollar, int)
DefineCurrency(TEuro, int)
echo($( 12.TDollar + 13.TDollar )) #OUT 25
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