Fix a bug in the pretty printer for arbitrary terms where it would not

Estimated hours taken: 0.2
Branches: main

library/pretty_printer.m:
	Fix a bug in the pretty printer for arbitrary terms where it would not
	start a new line for a functor that could not fit on the remainder of
	the line.  This made it impossible to see structure from indentation in
	some cases.

tests/hard_coded/test_pretty_printer.exp:
tests/hard_coded/test_pretty_printer.m:
	Update the test case.

library/pretty_printer.m

@@ -1,7 +1,7 @@
 %-----------------------------------------------------------------------------%
 % vim: ts=4 sw=4 expandtab tw=0 wm=0 ft=mercury
 %-----------------------------------------------------------------------------%
-% Copyright (C) 2007 The University of Melbourne
+% Copyright (C) 2007, 2009 The University of Melbourne
 % This file may only be copied under the terms of the GNU Library General
 % Public License - see the file COPYING.LIB in the Mercury distribution.
 %-----------------------------------------------------------------------------%
@@ -712,7 +712,8 @@ expand_format_term(Name, Args, Doc, !Limit, CurrentPri) :-
             str("{"), indent([format_list(Args, str(", "))]), str("}")
         ])
       else
-        Doc0 = docs([
+        Doc0 = group([
+            nl,
             str(term_io.quoted_atom(Name)),
             str("("), indent([format_list(Args, str(", "))]), str(")")
         ])

tests/hard_coded/test_pretty_printer.exp

@@ -30,6 +30,11 @@ limit = triangular(1), max lines = 3, line width = 38
 100....
 |------------------------------------|
 
+limit = triangular(1), max lines = 3, line width = 38
+|------------------------------------|
+succ(...)
+|------------------------------------|
+
 limit = triangular(1), max lines = 3, line width = 38
 |------------------------------------|
 -...
@@ -86,6 +91,11 @@ limit = triangular(1), max lines = 3, line width = 78
 100....
 |----------------------------------------------------------------------------|
 
+limit = triangular(1), max lines = 3, line width = 78
+|----------------------------------------------------------------------------|
+succ(...)
+|----------------------------------------------------------------------------|
+
 limit = triangular(1), max lines = 3, line width = 78
 |----------------------------------------------------------------------------|
 -...
@@ -145,6 +155,11 @@ limit = triangular(1), max lines = 10, line width = 38
 100....
 |------------------------------------|
 
+limit = triangular(1), max lines = 10, line width = 38
+|------------------------------------|
+succ(...)
+|------------------------------------|
+
 limit = triangular(1), max lines = 10, line width = 38
 |------------------------------------|
 -...
@@ -204,6 +219,11 @@ limit = triangular(1), max lines = 10, line width = 78
 100....
 |----------------------------------------------------------------------------|
 
+limit = triangular(1), max lines = 10, line width = 78
+|----------------------------------------------------------------------------|
+succ(...)
+|----------------------------------------------------------------------------|
+
 limit = triangular(1), max lines = 10, line width = 78
 |----------------------------------------------------------------------------|
 -...
@@ -260,6 +280,11 @@ limit = linear(1), max lines = 3, line width = 38
 100....
 |------------------------------------|
 
+limit = linear(1), max lines = 3, line width = 38
+|------------------------------------|
+succ(...)
+|------------------------------------|
+
 limit = linear(1), max lines = 3, line width = 38
 |------------------------------------|
 -...
@@ -316,6 +341,11 @@ limit = linear(1), max lines = 3, line width = 78
 100....
 |----------------------------------------------------------------------------|
 
+limit = linear(1), max lines = 3, line width = 78
+|----------------------------------------------------------------------------|
+succ(...)
+|----------------------------------------------------------------------------|
+
 limit = linear(1), max lines = 3, line width = 78
 |----------------------------------------------------------------------------|
 -...
@@ -375,6 +405,11 @@ limit = linear(1), max lines = 10, line width = 38
 100....
 |------------------------------------|
 
+limit = linear(1), max lines = 10, line width = 38
+|------------------------------------|
+succ(...)
+|------------------------------------|
+
 limit = linear(1), max lines = 10, line width = 38
 |------------------------------------|
 -...
@@ -434,6 +469,11 @@ limit = linear(1), max lines = 10, line width = 78
 100....
 |----------------------------------------------------------------------------|
 
+limit = linear(1), max lines = 10, line width = 78
+|----------------------------------------------------------------------------|
+succ(...)
+|----------------------------------------------------------------------------|
+
 limit = linear(1), max lines = 10, line width = 78
 |----------------------------------------------------------------------------|
 -...
@@ -493,6 +533,14 @@ limit = triangular(10), max lines = 3, line width = 38
 100.99.98.97.96........
 |------------------------------------|
 
+limit = triangular(10), max lines = 3, line width = 38
+|------------------------------------|
+succ(
+  succ(
+    succ(
+      ...
+|------------------------------------|
+
 limit = triangular(10), max lines = 3, line width = 38
 |------------------------------------|
 -(-(-(-((... + ...) * ... / 
@@ -560,6 +608,11 @@ limit = triangular(10), max lines = 3, line width = 78
 100.99.98.97.96........
 |----------------------------------------------------------------------------|
 
+limit = triangular(10), max lines = 3, line width = 78
+|----------------------------------------------------------------------------|
+succ(succ(succ(succ(succ(succ(succ(succ(succ(succ(...))))))))))
+|----------------------------------------------------------------------------|
+
 limit = triangular(10), max lines = 3, line width = 78
 |----------------------------------------------------------------------------|
 -(-(-(-((... + ...) * ... / (... * ...)) / (... / ... * ... + -...)) / 
@@ -629,6 +682,20 @@ limit = triangular(10), max lines = 10, line width = 38
 100.99.98.97.96........
 |------------------------------------|
 
+limit = triangular(10), max lines = 10, line width = 38
+|------------------------------------|
+succ(
+  succ(
+    succ(
+      succ(
+        succ(
+          succ(
+            succ(
+              succ(
+                succ(
+                  succ(...))))))))))
+|------------------------------------|
+
 limit = triangular(10), max lines = 10, line width = 38
 |------------------------------------|
 -(-(-(-((... + ...) * ... / 
@@ -706,6 +773,11 @@ limit = triangular(10), max lines = 10, line width = 78
 100.99.98.97.96........
 |----------------------------------------------------------------------------|
 
+limit = triangular(10), max lines = 10, line width = 78
+|----------------------------------------------------------------------------|
+succ(succ(succ(succ(succ(succ(succ(succ(succ(succ(...))))))))))
+|----------------------------------------------------------------------------|
+
 limit = triangular(10), max lines = 10, line width = 78
 |----------------------------------------------------------------------------|
 -(-(-(-((... + ...) * ... / (... * ...)) / (... / ... * ... + -...)) / 
@@ -773,6 +845,14 @@ limit = triangular(100), max lines = 3, line width = 38
 ...
 |------------------------------------|
 
+limit = triangular(100), max lines = 3, line width = 38
+|------------------------------------|
+succ(
+  succ(
+    succ(
+      ...
+|------------------------------------|
+
 limit = triangular(100), max lines = 3, line width = 38
 |------------------------------------|
 -(-(-(-((x + x) * (x + x) / 
@@ -849,6 +929,11 @@ limit = triangular(100), max lines = 3, line width = 78
 .......
 |----------------------------------------------------------------------------|
 
+limit = triangular(100), max lines = 3, line width = 78
+|----------------------------------------------------------------------------|
+succ(succ(succ(succ(succ(succ(succ(succ(succ(succ(zero))))))))))
+|----------------------------------------------------------------------------|
+
 limit = triangular(100), max lines = 3, line width = 78
 |----------------------------------------------------------------------------|
 -(-(-(-((x + x) * (x + x) / (x / x * (x / x))) / 
@@ -936,6 +1021,20 @@ limit = triangular(100), max lines = 10, line width = 38
 52.51........
 |------------------------------------|
 
+limit = triangular(100), max lines = 10, line width = 38
+|------------------------------------|
+succ(
+  succ(
+    succ(
+      succ(
+        succ(
+          succ(
+            succ(
+              succ(
+                succ(
+                  succ(zero))))))))))
+|------------------------------------|
+
 limit = triangular(100), max lines = 10, line width = 38
 |------------------------------------|
 -(-(-(-((x + x) * (x + x) / 
@@ -1049,6 +1148,11 @@ limit = triangular(100), max lines = 10, line width = 78
 .......
 |----------------------------------------------------------------------------|
 
+limit = triangular(100), max lines = 10, line width = 78
+|----------------------------------------------------------------------------|
+succ(succ(succ(succ(succ(succ(succ(succ(succ(succ(zero))))))))))
+|----------------------------------------------------------------------------|
+
 limit = triangular(100), max lines = 10, line width = 78
 |----------------------------------------------------------------------------|
 -(-(-(-((x + x) * (x + x) / (x / x * (x / x))) / 
@@ -1139,6 +1243,14 @@ limit = linear(10), max lines = 3, line width = 38
 100.99.98.97.96........
 |------------------------------------|
 
+limit = linear(10), max lines = 3, line width = 38
+|------------------------------------|
+succ(
+  succ(
+    succ(
+      ...
+|------------------------------------|
+
 limit = linear(10), max lines = 3, line width = 38
 |------------------------------------|
 -(-(-(-((... + ...) * ... / ...) / 
@@ -1200,6 +1312,11 @@ limit = linear(10), max lines = 3, line width = 78
 100.99.98.97.96........
 |----------------------------------------------------------------------------|
 
+limit = linear(10), max lines = 3, line width = 78
+|----------------------------------------------------------------------------|
+succ(succ(succ(succ(succ(succ(succ(succ(succ(succ(...))))))))))
+|----------------------------------------------------------------------------|
+
 limit = linear(10), max lines = 3, line width = 78
 |----------------------------------------------------------------------------|
 -(-(-(-((... + ...) * ... / ...) / ...) / ...) / ...)
@@ -1259,6 +1376,20 @@ limit = linear(10), max lines = 10, line width = 38
 100.99.98.97.96........
 |------------------------------------|
 
+limit = linear(10), max lines = 10, line width = 38
+|------------------------------------|
+succ(
+  succ(
+    succ(
+      succ(
+        succ(
+          succ(
+            succ(
+              succ(
+                succ(
+                  succ(...))))))))))
+|------------------------------------|
+
 limit = linear(10), max lines = 10, line width = 38
 |------------------------------------|
 -(-(-(-((... + ...) * ... / ...) / 
@@ -1323,6 +1454,11 @@ limit = linear(10), max lines = 10, line width = 78
 100.99.98.97.96........
 |----------------------------------------------------------------------------|
 
+limit = linear(10), max lines = 10, line width = 78
+|----------------------------------------------------------------------------|
+succ(succ(succ(succ(succ(succ(succ(succ(succ(succ(...))))))))))
+|----------------------------------------------------------------------------|
+
 limit = linear(10), max lines = 10, line width = 78
 |----------------------------------------------------------------------------|
 -(-(-(-((... + ...) * ... / ...) / ...) / ...) / ...)
@@ -1385,6 +1521,14 @@ limit = linear(100), max lines = 3, line width = 38
 ...
 |------------------------------------|
 
+limit = linear(100), max lines = 3, line width = 38
+|------------------------------------|
+succ(
+  succ(
+    succ(
+      ...
+|------------------------------------|
+
 limit = linear(100), max lines = 3, line width = 38
 |------------------------------------|
 -(-(-(-((x + x) * (x + x) / 
@@ -1461,6 +1605,11 @@ limit = linear(100), max lines = 3, line width = 78
 .......
 |----------------------------------------------------------------------------|
 
+limit = linear(100), max lines = 3, line width = 78
+|----------------------------------------------------------------------------|
+succ(succ(succ(succ(succ(succ(succ(succ(succ(succ(zero))))))))))
+|----------------------------------------------------------------------------|
+
 limit = linear(100), max lines = 3, line width = 78
 |----------------------------------------------------------------------------|
 -(-(-(-((x + x) * (x + x) / (x / x * (x / x))) / 
@@ -1548,6 +1697,20 @@ limit = linear(100), max lines = 10, line width = 38
 52.51........
 |------------------------------------|
 
+limit = linear(100), max lines = 10, line width = 38
+|------------------------------------|
+succ(
+  succ(
+    succ(
+      succ(
+        succ(
+          succ(
+            succ(
+              succ(
+                succ(
+                  succ(zero))))))))))
+|------------------------------------|
+
 limit = linear(100), max lines = 10, line width = 38
 |------------------------------------|
 -(-(-(-((x + x) * (x + x) / 
@@ -1661,6 +1824,11 @@ limit = linear(100), max lines = 10, line width = 78
 .......
 |----------------------------------------------------------------------------|
 
+limit = linear(100), max lines = 10, line width = 78
+|----------------------------------------------------------------------------|
+succ(succ(succ(succ(succ(succ(succ(succ(succ(succ(zero))))))))))
+|----------------------------------------------------------------------------|
+
 limit = linear(100), max lines = 10, line width = 78
 |----------------------------------------------------------------------------|
 -(-(-(-((x + x) * (x + x) / (x / x * (x / x))) / 

tests/hard_coded/test_pretty_printer.m

@@ -52,6 +52,10 @@
     ;       op_tree * op_tree
     ;       op_tree / op_tree.
 
+:- type church
+    --->    zero
+    ;       succ(church).
+
 :- type non_canonical_bool
     --->    non_canonical_bool(int)
     where equality is non_canonical_bool_eq.
@@ -209,6 +213,7 @@ test_case(test_case(LineWidth, MaxLines, Limit, Doc)) :-
         func(X, M) = M ^ elem(X) := float(X),
         List, map.init : map(int, float)),
     OpTree = mk_op_tree(200),
+    Church = list.foldl(func(_, X) = succ(X), 1..10, zero),
     Tuple = {1, 2.0, "three", '4', {5}},
     Square = list.duplicate(10, 1..10) : list(list(int)),
     IndentTest = docs([
@@ -243,6 +248,7 @@ test_case(test_case(LineWidth, MaxLines, Limit, Doc)) :-
     ;   Doc = format(MapFloat)
     ;   Doc = format(MapStr)
     ;   Doc = format(OpTree)
+    ;   Doc = format(Church)
     ;   Doc = fmt_susp_seq(100)
     ;   Doc = format(Tuple)
     ;   Doc = format(Square)