Does Idris have an equivalent to Agda's `_` expressions?

Question

In addition to having implicit arguments, Agda lets you omit the value of an explicit argument and replace it with a metavariable, denoted by the _ character, whose value is then determined through the same procedure as implicit resolution.

Does Idris have a similar feature, or are implicit arguments the only way of introducing metavariables into programs?

score 8 · Accepted Answer · answered Mar 11 '16 at 13:18

8

You can use _ in Idris as well.

import Data.Vect

foo : (n : Nat) -> Vect n a -> Vect n a
foo n xs = xs

bar : Vect 3 Nat
bar = foo _ [1, 2, 3]   -- works

answered Mar 11 '16 at 13:18

Andy Morris

720
3
10

Looks like I missed this, thought it was invalid because I had other syntax errors! Either way, it's not very clearly documented. Thanks! – jmite Mar 14 '16 at 20:30

Does Idris have an equivalent to Agda's `_` expressions?

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