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I am writing a function that does piecewise multiplication of two arrays.
xs.iter()
.zip(ys).map(|(x, y)| x * y)
.sum()
In some other languages, I can pass (*) as a function to map. Does Rust have this feature?
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Infix notation is the notation commonly used in arithmetical and logical formulae and statements. It is characterized by the placement of operators between operands—"infixed operators"—such as the plus sign in 2 + 2.
The operands of all of these operators are evaluated in value expression context so are moved or copied. * Integer division rounds towards zero. ** Rust uses a remainder defined with truncating division. Given remainder = dividend % divisor , the remainder will have the same sign as the dividend.
An infix operator allows a function to be called between two given arguments. A postfix operator just places the arguments prior to the function operation.
k-infix makes writing infix expressions in Racket easy. It's extensible as one can add operators freely. k-infix supports prefix, postfix, and binary operators. Left and right -associativity are also supported.
Nnnyes. Sorta kinda not really.
You can't write an operator as a name. But most operators are backed by traits, and you can write the name of those, so a * b is effectively Mul::mul(a, b), and you can pass Mul::mul as a function pointer.
But that doesn't help in this case because Iterator::map is expecting a FnMut((A, B)) -> C, and the binary operators all implement FnMut(A, B) -> C.
Now, you could write an adapter for this, but you'd need one for every combination of arity and mutability. And you'd have to eat a heap allocation and indirection or require a nightly compiler.
Or, you could write your own version of Iterator::map on an extension trait that accepts higher arity functions for iterators of tuples... again, one for each arity...
Honestly, it's simpler to just use a closure.
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