feat(builtin/macros): rename 'For' macro to 'take'

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

examples/lean/set.lean

@@ -9,30 +9,30 @@ Definition subset {A : Type} (s1 : Set A) (s2 : Set A) := ∀ x, x ∈ s1 ⇒ x
 Infix 50 ⊆ : subset
 
 Theorem SubsetTrans (A : Type) : ∀ s1 s2 s3 : Set A, s1 ⊆ s2 ⇒ s2 ⊆ s3 ⇒ s1 ⊆ s3 :=
-   For s1 s2 s3, Assume (H1 : s1 ⊆ s2) (H2 : s2 ⊆ s3),
+   take s1 s2 s3, Assume (H1 : s1 ⊆ s2) (H2 : s2 ⊆ s3),
       show s1 ⊆ s3,
-        For x, Assume Hin : x ∈ s1,
+        take x, Assume Hin : x ∈ s1,
            show x ∈ s3,
              let L1 : x ∈ s2 := MP (Instantiate H1 x) Hin
              in MP (Instantiate H2 x) L1
 
 Theorem SubsetExt (A : Type) : ∀ s1 s2 : Set A, (∀ x, x ∈ s1 = x ∈ s2) ⇒ s1 = s2 :=
-   For s1 s2, Assume (H : ∀ x, x ∈ s1 = x ∈ s2),
+   take s1 s2, Assume (H : ∀ x, x ∈ s1 = x ∈ s2),
        Abst (fun x, Instantiate H x)
 
 Theorem SubsetAntiSymm (A : Type) : ∀ s1 s2 : Set A, s1 ⊆ s2 ⇒ s2 ⊆ s1 ⇒ s1 = s2 :=
-   For s1 s2, Assume (H1 : s1 ⊆ s2) (H2 : s2 ⊆ s1),
+   take s1 s2, Assume (H1 : s1 ⊆ s2) (H2 : s2 ⊆ s1),
        show s1 = s2,
             MP (show (∀ x, x ∈ s1 = x ∈ s2) ⇒ s1 = s2,
                      Instantiate (SubsetExt A) s1 s2)
                (show (∀ x, x ∈ s1 = x ∈ s2),
-                     For x, show x ∈ s1 = x ∈ s2,
+                     take x, show x ∈ s1 = x ∈ s2,
                                  let L1 : x ∈ s1 ⇒ x ∈ s2 := Instantiate H1 x,
                                      L2 : x ∈ s2 ⇒ x ∈ s1 := Instantiate H2 x
                                      in ImpAntisym L1 L2)
 
 -- Compact (but less readable) version of the previous theorem
 Theorem SubsetAntiSymm2 (A : Type) : ∀ s1 s2 : Set A, s1 ⊆ s2 ⇒ s2 ⊆ s1 ⇒ s1 = s2 :=
-   For s1 s2, Assume H1 H2,
+   take s1 s2, Assume H1 H2,
       MP (Instantiate (SubsetExt A) s1 s2)
-         (For x, ImpAntisym (Instantiate H1 x) (Instantiate H2 x))
+         (take x, ImpAntisym (Instantiate H1 x) (Instantiate H2 x))

src/builtin/macros.lua

@@ -83,7 +83,7 @@ function nary_macro(name, f, farity)
    end)
 end
 
-binder_macro("For", Const("ForallIntro"), 3, 1, 3)
+binder_macro("take", Const("ForallIntro"), 3, 1, 3)
 binder_macro("Assume", Const("Discharge"), 3, 1, 3)
 nary_macro("Instantiate", Const("ForallElim"), 4)
 nary_macro("MP'", Const("MP"), 4)

tests/lean/subst3.lean

@@ -1,7 +1,7 @@
 (* import("macros.lua") *)
 
 Theorem T (A : Type) (p : A -> Bool) (f : A -> A -> A) : forall x y z, p (f x x) => x = y => x = z => p (f y z) :=
-   For x y z, Assume (H1 : p (f x x)) (H2 : x = y) (H3 : x = z),
+   take x y z, Assume (H1 : p (f x x)) (H2 : x = y) (H3 : x = z),
       Subst' H1 H2 H3.
 
 print Environment 1.