fixup! compiler: Add zip generators for comprehensions

lib/compiler/src/v3_core.erl

@@ -1662,46 +1662,47 @@ zip_tq(Line, E, #izip{arg=[#igen{anno=#a{anno=GA}=GAnno,
 
     %% Generate the clauses for the letrec.
     AccPats = collect_for_zip(accpats, Generators),
-    {Cs, St} =
-        case member(nomatch, AccPats) of
-            true -> 
-                %% At least one generator will never match.
-                {[], St3};
+
+    TailVars = collect_for_zip(tails, Generators),
+    Nc = #iapply{anno=GAnno,op=F,args=TailVars},
+    {Lc,Lps,St4} = lc_tq(Line, E, Qs, Nc, St3),
+
+    AccClause = case member(nomatch, AccPats) of
+                    true ->
+                        nomatch;
+                    false ->
+                        make_clause(LA, AccPats, AccGuard, Lps++[Lc])
+                end,
+
+    TailPats = collect_for_zip(tailpats, Generators),
+    TailClause = make_clause(LA, TailPats, [], [Mc]),
+
+    SkipPats = collect_for_zip(skip_pats, Generators),
+    SkipClause = make_clause(LA, SkipPats, [], [Nc]),
+
+    RefillPats0 = collect_for_zip(refillpats, Generators),
+    RefillClause =
+        case all(fun(X) -> X =:= nomatch end, RefillPats0) of
+            true ->
+                %% There are no map generators.
+                nomatch;
             false ->
-                TailVars = collect_for_zip(tails, Generators),
-                Nc = #iapply{anno=GAnno,op=F,args=TailVars},
-                {Lc,Lps,St4} = lc_tq(Line, E, Qs, Nc, St3),
-
-                AccClause = make_clause(LA, AccPats, AccGuard, Lps++[Lc]),
-
-                TailPats = collect_for_zip(tailpats, Generators),
-                TailClause = make_clause(LA, TailPats, [], [Mc]),
-
-                RefillPats0 = collect_for_zip(refillpats, Generators),
-                RefillClause =
-                    case all(fun(X) -> X =:= nomatch end, RefillPats0) of
-                        true ->
-                            %% There are no map generators.
-                            [];
-                        false -> 
-                            RefillPats = make_ignored(RefillPats0, TailVars),
-                            RefillAs = collect_for_zip(refillas, Generators),
-                            RefillBody = [C || C <- RefillAs, C =/= ignore],
-                            [make_clause(LA, RefillPats, [], RefillBody++[Nc])]
-                    end,
-
-                Cs0 = [AccClause, TailClause | RefillClause],
-                Cs1 = [C || C <- Cs0, C =/= nomatch],
-                {Cs1, St4}
+                RefillPats = make_ignored(RefillPats0, TailVars),
+                RefillAs = collect_for_zip(refillas, Generators),
+                RefillBody = [C || C <- RefillAs, C =/= ignore],
+                make_clause(LA, RefillPats, [], RefillBody++[Nc])
         end,
 
+    Cs0 = [AccClause, TailClause, SkipClause, RefillClause],
+    Cs = [C || C <- Cs0, C =/= nomatch],
+
     Fc = bad_generators(FcVars, Arg, lc),
     Fun = #ifun{anno=GAnno,id=[],vars=CallVars,clauses=Cs,fc=Fc},
     {#iletrec{anno=GAnno#a{anno=[list_comprehension|GA]},
               defs=[{{Name,NumGenerators},Fun}],
               body=append(collect_for_zip(pres, Generators)) ++
                   [#iapply{anno=GAnno,op=F,args=collect_for_zip(args, Generators)}]},
-     [],St}.
+     [],St4}.
 
 %% bc_tq(Line, Exp, [Qualifier], More, State) -> {LetRec,[PreExp],State}.
 %%  This TQ from Gustafsson ERLANG'05.  
@@ -1891,7 +1892,9 @@ collect_for_zip(What, Qs) ->
             refillas ->
                 fun(#igen{refill={_, R}}) -> R end;
             pres ->
-                fun(#igen{arg={Pre, _}}) -> Pre end
+                fun(#igen{arg={Pre, _}}) -> Pre end;
+            skip_pats ->
+                fun(#igen{skip_pat=SkipPat}) -> SkipPat end
         end,
     [F(Q) || #igen{} = Q <- Qs].
 

lib/compiler/test/zlc_SUITE.erl

@@ -74,6 +74,7 @@ basic(Config) when is_list(Config) ->
     mixed_zlc(),
     zmc(),
     filter_guard(),
+    filter_pattern(),
     cartesian(),
     nomatch(),
     bad_generators().
@@ -146,6 +147,27 @@ filter_guard() ->
     #{c := 3} = #{X => Y || X <- [a,b,c] && Y <- [1,2,3], Y rem 2 == 1, Y > 1},
     #{c := 3,a := 1} = #{X => Y || X <- [a,b,c] && <<Y>> <= <<1,2,3>>, Y rem 2 == 1}.
 
+filter_pattern() ->
+    [] = do_filter_pat_1([], []),
+    [] = do_filter_pat_1([a], [a]),
+    [] = do_filter_pat_1([{ok,a}], [{error,e}]),
+
+
+    [] = do_filter_pat_2([], []),
+    [] = do_filter_pat_2([a], [b]),
+    [] = do_filter_pat_2([{a,1}], [{b,1}]),
+    [{1,7}] = do_filter_pat_2([{a,1}], [{a,7}]),
+    [{1,7},{10,20}] = do_filter_pat_2([{a,1},{b,9},{x,10}],
+                                      [{a,7},{wrong,8},{x,20}]),
+
+    ok.
+
+do_filter_pat_1(L1, L2) ->
+    [{A,B} || {ok,A} <- L1 && {ok,B} <- L2].
+
+do_filter_pat_2(L1, L2) ->
+    [{A,B} || {Same,A} <- L1 && {Same,B} <- L2].
+
 cartesian() ->
     [{a, 3}, {b, 5}, {c, 7}, {a, 4}, {b, 6}, {c, 8}] = [{X, W+Y} || W <- [1,2],
                                                                     X <- [a, b, c] && <<Y>> <= <<2, 4, 6>>],
@@ -159,13 +181,23 @@ cartesian() ->
     ok.
 
 nomatch() ->
-    {'EXIT',{{bad_generators,{[a,b],[c]}},_}} = (catch [{X, Y} || a=b=X <- [a,b] &&
-                                                                      Y <- [c]]),
-    {'EXIT',{{bad_generators,{[1,2],<<3>>}},_}} = (catch 
-                                                       << <<(X+Y)/integer>> || a=b=X <- [1,2] &&
-                                                                                   <<Y>> <= <<3>> >>).
+    [] = do_nomatch_1([], []),
+    [] = do_nomatch_1([1], [a]),
+    [] = do_nomatch_1([1,2], [a,b]),
+    {'EXIT',{{bad_generators,{[1,2,3],[]}},_}} = do_nomatch_1([1,2,3], []),
+    {'EXIT',{{bad_generators,{[3],[]}},_}} = do_nomatch_1([1,2,3], [a,b]),
 
-id(I) -> I.
+    %% <<>> = do_nomatch_2([], <<>>),
+    %% <<>> = do_nomatch_2([a], <<1>>),
+    {'EXIT',{{bad_generators,{[1,2],<<3>>}},_}} = do_nomatch_2([1,2], <<3>>),
+
+    ok.
+
+do_nomatch_1(L1, L2) ->
+    catch [{X, Y} || a=b=X <- L1 && Y <- L2].
+
+do_nomatch_2(L, Bin) ->
+    catch << <<(X+Y)/integer>> || a=b=X <- L && <<Y>> <= Bin >>.
 
 bad_generators() ->
 
@@ -214,6 +246,11 @@ bad_generators() ->
     end,
     ok.
 
+%%% Common utilities.
+
+id(I) -> I.
+
+
 -file("bad_zlc.erl", 1).
 bad_generators(L1,L2) ->                        %Line 2
     [{I1, I2} ||                                %Line 3