stdlib: Let the Pretty Printer output more on one line

Atomic elements such as atoms, '{}', '[]', and '<<>>' are output on
the same line in types, structs, lists, &c.

In particular types can be more compact, and easier to read.

A space is output after comma in tuples, to be more consistent.

1 files changed, 50 insertions, 7 deletions

diff --git a/lib/stdlib/test/erl_pp_SUITE.erl b/lib/stdlib/test/erl_pp_SUITE.erl
index c79e29eb11..3eb1670806 100644
--- a/lib/stdlib/test/erl_pp_SUITE.erl
+++ b/lib/stdlib/test/erl_pp_SUITE.erl
@@ -52,7 +52,7 @@
 	  otp_6321/1, otp_6911/1, otp_6914/1, otp_8150/1, otp_8238/1,
 	  otp_8473/1, otp_8522/1, otp_8567/1, otp_8664/1, otp_9147/1,
           otp_10302/1, otp_10820/1, otp_11100/1, otp_11861/1, pr_1014/1,
-          otp_13662/1, otp_14285/1, otp_15592/1, otp_15751/1]).
+          otp_13662/1, otp_14285/1, otp_15592/1, otp_15751/1, otp_15755/1]).
 
 %% Internal export.
 -export([ehook/6]).
@@ -82,7 +82,7 @@ groups() ->
       [otp_6321, otp_6911, otp_6914, otp_8150, otp_8238,
        otp_8473, otp_8522, otp_8567, otp_8664, otp_9147,
        otp_10302, otp_10820, otp_11100, otp_11861, pr_1014, otp_13662,
-       otp_14285, otp_15592, otp_15751]}].
+       otp_14285, otp_15592, otp_15751, otp_15755]}].
 
 init_per_suite(Config) ->
     Config.
@@ -474,10 +474,10 @@ cond1(Config) when is_list(Config) ->
                     [{tuple,5,[{atom,5,x},{atom,5,y}]}]}]},
     CChars = flat_expr1(C),
     "cond\n"
-          "    {foo,bar} ->\n"
-          "        [a,b];\n"
+          "    {foo, bar} ->\n"
+          "        [a, b];\n"
           "    true ->\n"
-          "        {x,y}\n"
+          "        {x, y}\n"
           "end" = CChars,
     ok.
 
@@ -712,7 +712,7 @@ otp_6321(Config) when is_list(Config) ->
     Str = "S = hopp, {hej, S}. ",
     {done, {ok, Tokens, _EndLine}, ""} = erl_scan:tokens("", Str, _L=1),
     {ok, Exprs} = erl_parse:parse_exprs(Tokens),
-    "S = hopp, {hej,S}" = lists:flatten(erl_pp:exprs(Exprs)),
+    "S = hopp, {hej, S}" = lists:flatten(erl_pp:exprs(Exprs)),
     ok.
 
 %% OTP_6911. More newlines.
@@ -1112,7 +1112,7 @@ otp_11861(Config) when is_list(Config) ->
     A3 = erl_anno:new(3),
     "-optional_callbacks([bar/0]).\n" =
         pf({attribute,A3,optional_callbacks,[{bar,0}]}),
-    "-optional_callbacks([{bar,1,bad}]).\n" =
+    "-optional_callbacks([{bar, 1, bad}]).\n" =
         pf({attribute,A3,optional_callbacks,[{bar,1,bad}]}),
     ok.
 
@@ -1221,6 +1221,46 @@ otp_15751(_Config) ->
                     end">>),
     ok.
 
+otp_15755(_Config) ->
+    "[{a, b}, c, {d, e} | t]" =
+        flat_parse_and_pp_expr("[{a, b}, c, {d, e} | t]", 0, []),
+    "[{a, b},\n c, d,\n {d, e},\n 1, 2.0,\n {d, e},\n <<>>, {},\n {d, e},\n"
+    " [], [],\n {d, e} |\n t]" =
+        flat_parse_and_pp_expr("[{a,b},c,d,{d,e},1,2.0,{d,e},<<>>,"
+                               "{},{d,e},[],[],{d,e}|t]", 0, []),
+    "[{a, b},\n c, d,\n {d, e},\n 1, 2.0,\n {d, e},\n <<>>, {},\n {d, e},\n"
+    " [], [], d, e | t]" =
+        flat_parse_and_pp_expr("[{a,b},c,d,{d,e},1,2.0,{d,e},<<>>,"
+                               "{},{d,e},[],[],d,e|t]", 0, []),
+
+    "-type t() ::
+          a | b | c | a | b | a | b | a | b | a | b | a | b | a | b |
+          a | b | a | b | a | b.\n" =
+        lists:flatten(parse_and_pp_forms(
+             "-type t() :: a | b | c| a | b | a | b | a | b | a |"
+             " b | a | b | a | b | a | b | a | b |a | b.", [])),
+
+    "-type t() ::
+          {dict, 0, 16, 16, 8, 80, 48,
+           {[], [], [], [], [], [], [], [], [], [], [], [], [], [], [],
+            []},
+           {{[], [], [], [], [], [], [], [], [], [], [], [], [], [], []}}}.\n" =
+        lists:flatten(parse_and_pp_forms(
+             "-type t() :: {dict,0,16,16,8,80,48,"
+             "{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},"
+             "{{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]}}}.", [])),
+
+    "-type t() ::
+          {{a},
+           0, 16,
+           {16},
+           8, 80, 48, a, b, e, f, 'sf s sdf', [], {},
+           {[]}}.\n" =
+        lists:flatten(parse_and_pp_forms(
+             "-type t() :: {{a}, 0, 16, {16}, 8, 80, 48, a, b, e, f,"
+             " 'sf s sdf', [], {}, {[]}}.", [])),
+    ok.
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 compile(Config, Tests) ->
@@ -1352,6 +1392,9 @@ pp_expr(List, Options) when is_list(List) ->
             not_ok
     end.
 
+flat_parse_and_pp_expr(String, Indent, Options) ->
+    lists:flatten(parse_and_pp_expr(String, Indent, Options)).
+
 parse_and_pp_expr(String, Indent, Options) ->
     StringDot = lists:flatten(String) ++ ".",
     erl_pp:expr(parse_expr(StringDot), Indent, Options).