From 4ae19de755595dac30046d94d929ce49ff8dbc25 Mon Sep 17 00:00:00 2001
From: Robbert Krebbers <mail@robbertkrebbers.nl>
Date: Mon, 8 Jul 2019 21:07:21 +0200
Subject: [PATCH] Let `lcons` return unit.

---
 theories/examples/map_reduce.v       |  2 +-
 theories/examples/sort.v             | 13 +++++--------
 theories/examples/sort_elem_client.v |  5 +++--
 theories/utils/llist.v               |  4 ++--
 4 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/theories/examples/map_reduce.v b/theories/examples/map_reduce.v
index 359c30f..b0080bd 100644
--- a/theories/examples/map_reduce.v
+++ b/theories/examples/map_reduce.v
@@ -65,7 +65,7 @@ Definition par_map_reduce_reduce_server : val :=
          send "cred" #false;; "go" ("n" - #1) "csort" "cred" NONE "zs"
       | SOME "acc" =>
          (* Read subsequent items with the same key *)
-         let: "ys" := lcons (Snd "acc") (lnil #()) in
+         let: "ys" := lnil #() in lcons (Snd "acc") "ys";;
          let: "new_acc" := par_map_reduce_collect "csort" (Fst "acc") "ys" in
          send "cred" #true;;
          send "cred" (Fst "acc", "ys");;
diff --git a/theories/examples/sort.v b/theories/examples/sort.v
index 0db0800..adc93fb 100644
--- a/theories/examples/sort.v
+++ b/theories/examples/sort.v
@@ -10,8 +10,8 @@ Definition lmerge : val :=
     let: "y" := lhead "ys" in
     let: "z" := lhead "zs" in
     if: "cmp" "y" "z"
-    then lpop "ys";; "go" "cmp" "ys" "zs";; lcons "y" "ys";; #()
-    else lpop "zs";; "go" "cmp" "ys" "zs";; lcons "z" "ys";; #().
+    then lpop "ys";; "go" "cmp" "ys" "zs";; lcons "y" "ys"
+    else lpop "zs";; "go" "cmp" "ys" "zs";; lcons "z" "ys".
 
 Definition sort_service : val :=
   rec: "go" "c" :=
@@ -69,14 +69,12 @@ Section sort.
       wp_apply (lpop_spec with "Hl1"); iIntros "Hl1".
       wp_apply ("IH" $! _ _ (x2 :: _) with "Hl1 Hl2 HI1' [$HI2 $HI2']").
       iIntros (ws) "[Hl1 HI]".
-      wp_apply (lcons_spec with "Hl1"); iIntros "Hl1".
-      wp_pures. iApply "HΨ". iFrame.
+      wp_apply (lcons_spec with "Hl1"); iIntros "Hl1". iApply "HΨ". iFrame.
     - rewrite decide_False //.
       wp_apply (lpop_spec with "Hl2"); iIntros "Hl2".
       wp_apply ("IH" $! _ (x1 :: _) with "Hl1 Hl2 [$HI1 $HI1'] HI2'").
       iIntros (ws) "[Hl1 HI]".
-      wp_apply (lcons_spec with "Hl1"); iIntros "Hl1".
-      wp_pures. iApply "HΨ". iFrame.
+      wp_apply (lcons_spec with "Hl1"); iIntros "Hl1". iApply "HΨ". iFrame.
   Qed.
 
   Lemma sort_service_spec p c :
@@ -84,8 +82,7 @@ Section sort.
       sort_service c
     {{{ RET #(); c ↣ p @ N }}}.
   Proof.
-    iIntros (Ψ) "Hc HΨ". iLöb as "IH" forall (p c Ψ).
-    wp_lam.
+    iIntros (Ψ) "Hc HΨ". iLöb as "IH" forall (p c Ψ). wp_lam.
     wp_recv (A I R ?? cmp) as "#Hcmp".
     wp_recv (xs l vs) as "[Hl HI]".
     wp_apply (llength_spec with "Hl"); iIntros "Hl".
diff --git a/theories/examples/sort_elem_client.v b/theories/examples/sort_elem_client.v
index bb2145e..9732425 100644
--- a/theories/examples/sort_elem_client.v
+++ b/theories/examples/sort_elem_client.v
@@ -13,7 +13,8 @@ Definition send_all : val :=
 Definition recv_all : val :=
   rec: "go" "c" :=
     if: ~recv "c" then lnil #() else
-    let: "x" := recv "c" in lcons "x" ("go" "c").
+    let: "x" := recv "c" in
+    let: "l" := "go" "c" in lcons "x" "l";; "l".
 
 Definition sort_elem_client : val :=
   λ: "cmp" "xs",
@@ -57,7 +58,7 @@ Section sort_elem_client.
     - wp_recv (y v) as (Htl) "HIxv".
       wp_apply ("IH" with "[] Hc"); first by auto using Sorted_snoc.
       iIntros (l ys ws). rewrite -!assoc_L. iDestruct 1 as (??) "(Hl & Hc & HI)".
-      wp_apply (lcons_spec with "Hl"); iIntros "Hl".
+      wp_apply (lcons_spec with "Hl"); iIntros "Hl"; wp_pures.
       iApply ("HΦ" $! _ (y :: ys)); simpl; eauto with iFrame.
     - wp_apply (lnil_spec with "[//]"); iIntros (l) "Hl".
       iApply ("HΦ" $! _ [] []); rewrite /= right_id_L; by iFrame.
diff --git a/theories/utils/llist.v b/theories/utils/llist.v
index 51e2423..f57d57c 100644
--- a/theories/utils/llist.v
+++ b/theories/utils/llist.v
@@ -10,7 +10,7 @@ Fixpoint llist `{heapG Σ} (l : loc) (vs : list val) : iProp Σ :=
 Arguments llist : simpl never.
 
 Definition lnil : val := λ: <>, ref NONE.
-Definition lcons : val := λ: "x" "l", "l" <- SOME ("x", ref (!"l"));; "l".
+Definition lcons : val := λ: "x" "l", "l" <- SOME ("x", ref (!"l")).
 
 Definition lisnil : val := λ: "l",
   match: !"l" with
@@ -83,7 +83,7 @@ Lemma lnil_spec :
 Proof. iIntros (Φ _) "HΦ". wp_lam. wp_alloc l. by iApply "HΦ". Qed.
 
 Lemma lcons_spec l v vs :
-  {{{ llist l vs }}} lcons v #l {{{ RET #l; llist l (v :: vs) }}}.
+  {{{ llist l vs }}} lcons v #l {{{ RET #(); llist l (v :: vs) }}}.
 Proof.
   iIntros (Φ) "Hll HΦ". wp_lam. destruct vs as [|v' vs]; simpl; wp_pures.
   - wp_load. wp_alloc k. wp_store. iApply "HΦ"; eauto with iFrame.
-- 
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