lean2/tests/lean/run/e8.lean
Leonardo de Moura 4f2e0c6d7f refactor(frontends/lean): add 'attribute' command
The new command provides a uniform way to set declaration attributes.
It replaces the commands: class, instance, coercion, multiple_instances,
reducible, irreducible
2015-01-24 20:23:21 -08:00

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prelude
precedence `+`:65
namespace nat
constant nat : Type.{1}
constant add : nat → nat → nat
infixl + := add
end nat
namespace int
open nat (nat)
constant int : Type.{1}
constant add : int → int → int
infixl + := add
constant of_nat : nat → int
attribute of_nat [coercion]
end int
-- Open "only" the notation and declarations from the namespaces nat and int
open [notations] nat
open [notations] int
open [decls] nat
open [decls] int
constants n m : nat
constants i j : int
check n + m
check i + j
-- The following check does not work, since we are not open the coercions
-- check n + i
-- Here is a possible trick for this kind of configuration
definition add_ni (a : nat) (b : int) := (of_nat a) + b
definition add_in (a : int) (b : nat) := a + (of_nat b)
infixl + := add_ni
infixl + := add_in
check i + n
check n + i