Add back optional record fields for 4 exercises

exercises/practice/clock/.meta/Example.roc

@@ -1,5 +1,5 @@
 Clock :: { hour : U8, minute : U8 }.{
-	create : { hour : I64, minute : I64 } -> Clock
+	create : { hour : I64 ?? 0, minute : I64 ?? 0 } -> Clock
 	create = |{ hour, minute }| {
 		hour24 = (hour % 24 + minute // 60) % 24
 		minute60 = minute % 60
@@ -20,14 +20,14 @@ Clock :: { hour : U8, minute : U8 }.{
 		"${zero_padded(hour)}:${zero_padded(minute)}"
 	}
 
-	add : Clock, { hour : I64, minute : I64 } -> Clock
+	add : Clock, { hour : I64 ?? 0, minute : I64 ?? 0 } -> Clock
 	add = |clock, { hour, minute }| {
 		total_hour = clock.hour.to_i64() + (hour % 24 + minute // 60)
 		total_minute = clock.minute.to_i64() + minute % 60
 		create({ hour: total_hour, minute: total_minute })
 	}
 
-	subtract : Clock, { hour : I64, minute : I64 } -> Clock
+	subtract : Clock, { hour : I64 ?? 0, minute : I64 ?? 0 } -> Clock
 	subtract = |clock, { hour, minute }| {
 		clock.add({ hour: -(hour % 24 + minute // 60), minute: -(minute % 60) })
 	}

exercises/practice/clock/.meta/plugins.py

@@ -1,4 +1,9 @@
 def to_hour_minute_record(input):
     hour = input.get("hour", 0)
     minute = input.get("minute", 0)
-    return f'{{hour: {hour}, minute: {minute}}}'
+    fields = []
+    if hour != 0:
+        fields.append(f"hour: {hour}")
+    if minute != 0:
+        fields.append(f"minute: {minute}")
+    return "{ " + ", ".join(fields) + " }" if fields else "{}"

exercises/practice/clock/.meta/template.j2

@@ -17,7 +17,7 @@ expect {
 {%- elif case["property"] in ["add", "subtract"] %}
 expect {
     clock = create({{ plugins.to_hour_minute_record(case["input"]) }})
-    result = clock.{{ case["property"] | to_snake }}({ hour: 0, minute: {{ case["input"]["value"] }} }).to_str()
+    result = clock.{{ case["property"] | to_snake }}({ minute: {{ case["input"]["value"] }} }).to_str()
     expected = {{ case["expected"] | to_roc }} 
     result == expected
 }

exercises/practice/clock/Clock.roc

@@ -1,5 +1,5 @@
 Clock :: { hour : U8, minute : U8 }.{
-	create : { hour : I64, minute : I64 } -> Clock
+	create : { hour : I64 ?? 0, minute : I64 ?? 0 } -> Clock
 	create = |{ hour, minute }| {
 		crash "Please implement the 'create' function"
 	}
@@ -9,12 +9,12 @@ Clock :: { hour : U8, minute : U8 }.{
 		crash "Please implement the 'to_str' function"
 	}
 
-	add : Clock, { hour : I64, minute : I64 } -> Clock
+	add : Clock, { hour : I64 ?? 0, minute : I64 ?? 0 } -> Clock
 	add = |clock, { hour, minute }| {
 		crash "Please implement the 'add' function"
 	}
 
-	subtract : Clock, { hour : I64, minute : I64 } -> Clock
+	subtract : Clock, { hour : I64 ?? 0, minute : I64 ?? 0 } -> Clock
 	subtract = |clock, { hour, minute }| {
 		crash "Please implement the 'subtract' function"
 	}

exercises/practice/clock/clock-test.roc

@@ -1,6 +1,6 @@
 # These tests are auto-generated with test data from:
 # https://github.com/exercism/problem-specifications/tree/main/exercises/clock/canonical-data.json
-# File last updated on 2026-08-01
+# File last updated on 2026-08-18
 
 import Clock exposing [create, add, subtract, to_str]
 
@@ -10,7 +10,7 @@ import Clock exposing [create, add, subtract, to_str]
 
 # on the hour
 expect {
-	clock = create({ hour: 8, minute: 0 })
+	clock = create({ hour: 8 })
 	result = clock.to_str()
 	expected = "08:00"
 	result == expected
@@ -26,23 +26,23 @@ expect {
 
 # midnight is zero hours
 expect {
-	clock = create({ hour: 24, minute: 0 })
+	clock = create({ hour: 24 })
 	result = clock.to_str()
 	expected = "00:00"
 	result == expected
 }
 
 # hour rolls over
 expect {
-	clock = create({ hour: 25, minute: 0 })
+	clock = create({ hour: 25 })
 	result = clock.to_str()
 	expected = "01:00"
 	result == expected
 }
 
 # hour rolls over continuously
 expect {
-	clock = create({ hour: 100, minute: 0 })
+	clock = create({ hour: 100 })
 	result = clock.to_str()
 	expected = "04:00"
 	result == expected
@@ -58,15 +58,15 @@ expect {
 
 # minutes roll over
 expect {
-	clock = create({ hour: 0, minute: 160 })
+	clock = create({ minute: 160 })
 	result = clock.to_str()
 	expected = "02:40"
 	result == expected
 }
 
 # minutes roll over continuously
 expect {
-	clock = create({ hour: 0, minute: 1723 })
+	clock = create({ minute: 1723 })
 	result = clock.to_str()
 	expected = "04:43"
 	result == expected
@@ -106,15 +106,15 @@ expect {
 
 # negative hour rolls over
 expect {
-	clock = create({ hour: -25, minute: 0 })
+	clock = create({ hour: -25 })
 	result = clock.to_str()
 	expected = "23:00"
 	result == expected
 }
 
 # negative hour rolls over continuously
 expect {
-	clock = create({ hour: -91, minute: 0 })
+	clock = create({ hour: -91 })
 	result = clock.to_str()
 	expected = "05:00"
 	result == expected
@@ -174,64 +174,64 @@ expect {
 
 # add minutes
 expect {
-	clock = create({ hour: 10, minute: 0 })
-	result = clock.add({ hour: 0, minute: 3 }).to_str()
+	clock = create({ hour: 10 })
+	result = clock.add({ minute: 3 }).to_str()
 	expected = "10:03"
 	result == expected
 }
 
 # add no minutes
 expect {
 	clock = create({ hour: 6, minute: 41 })
-	result = clock.add({ hour: 0, minute: 0 }).to_str()
+	result = clock.add({ minute: 0 }).to_str()
 	expected = "06:41"
 	result == expected
 }
 
 # add to next hour
 expect {
-	clock = create({ hour: 0, minute: 45 })
-	result = clock.add({ hour: 0, minute: 40 }).to_str()
+	clock = create({ minute: 45 })
+	result = clock.add({ minute: 40 }).to_str()
 	expected = "01:25"
 	result == expected
 }
 
 # add more than one hour
 expect {
-	clock = create({ hour: 10, minute: 0 })
-	result = clock.add({ hour: 0, minute: 61 }).to_str()
+	clock = create({ hour: 10 })
+	result = clock.add({ minute: 61 }).to_str()
 	expected = "11:01"
 	result == expected
 }
 
 # add more than two hours with carry
 expect {
-	clock = create({ hour: 0, minute: 45 })
-	result = clock.add({ hour: 0, minute: 160 }).to_str()
+	clock = create({ minute: 45 })
+	result = clock.add({ minute: 160 }).to_str()
 	expected = "03:25"
 	result == expected
 }
 
 # add across midnight
 expect {
 	clock = create({ hour: 23, minute: 59 })
-	result = clock.add({ hour: 0, minute: 2 }).to_str()
+	result = clock.add({ minute: 2 }).to_str()
 	expected = "00:01"
 	result == expected
 }
 
 # add more than one day (1500 min = 25 hrs)
 expect {
 	clock = create({ hour: 5, minute: 32 })
-	result = clock.add({ hour: 0, minute: 1500 }).to_str()
+	result = clock.add({ minute: 1500 }).to_str()
 	expected = "06:32"
 	result == expected
 }
 
 # add more than two days
 expect {
 	clock = create({ hour: 1, minute: 1 })
-	result = clock.add({ hour: 0, minute: 3500 }).to_str()
+	result = clock.add({ minute: 3500 }).to_str()
 	expected = "11:21"
 	result == expected
 }
@@ -243,63 +243,63 @@ expect {
 # subtract minutes
 expect {
 	clock = create({ hour: 10, minute: 3 })
-	result = clock.subtract({ hour: 0, minute: 3 }).to_str()
+	result = clock.subtract({ minute: 3 }).to_str()
 	expected = "10:00"
 	result == expected
 }
 
 # subtract to previous hour
 expect {
 	clock = create({ hour: 10, minute: 3 })
-	result = clock.subtract({ hour: 0, minute: 30 }).to_str()
+	result = clock.subtract({ minute: 30 }).to_str()
 	expected = "09:33"
 	result == expected
 }
 
 # subtract more than an hour
 expect {
 	clock = create({ hour: 10, minute: 3 })
-	result = clock.subtract({ hour: 0, minute: 70 }).to_str()
+	result = clock.subtract({ minute: 70 }).to_str()
 	expected = "08:53"
 	result == expected
 }
 
 # subtract across midnight
 expect {
-	clock = create({ hour: 0, minute: 3 })
-	result = clock.subtract({ hour: 0, minute: 4 }).to_str()
+	clock = create({ minute: 3 })
+	result = clock.subtract({ minute: 4 }).to_str()
 	expected = "23:59"
 	result == expected
 }
 
 # subtract more than two hours
 expect {
-	clock = create({ hour: 0, minute: 0 })
-	result = clock.subtract({ hour: 0, minute: 160 }).to_str()
+	clock = create({})
+	result = clock.subtract({ minute: 160 }).to_str()
 	expected = "21:20"
 	result == expected
 }
 
 # subtract more than two hours with borrow
 expect {
 	clock = create({ hour: 6, minute: 15 })
-	result = clock.subtract({ hour: 0, minute: 160 }).to_str()
+	result = clock.subtract({ minute: 160 }).to_str()
 	expected = "03:35"
 	result == expected
 }
 
 # subtract more than one day (1500 min = 25 hrs)
 expect {
 	clock = create({ hour: 5, minute: 32 })
-	result = clock.subtract({ hour: 0, minute: 1500 }).to_str()
+	result = clock.subtract({ minute: 1500 }).to_str()
 	expected = "04:32"
 	result == expected
 }
 
 # subtract more than two days
 expect {
 	clock = create({ hour: 2, minute: 20 })
-	result = clock.subtract({ hour: 0, minute: 3000 }).to_str()
+	result = clock.subtract({ minute: 3000 }).to_str()
 	expected = "00:20"
 	result == expected
 }
@@ -366,8 +366,8 @@ expect {
 
 # clocks with minute overflow
 expect {
-	clock1 = create({ hour: 0, minute: 1 })
-	clock2 = create({ hour: 0, minute: 1441 })
+	clock1 = create({ minute: 1 })
+	clock2 = create({ minute: 1441 })
 	clock1 == clock2
 }
 
@@ -415,8 +415,8 @@ expect {
 
 # full clock and zeroed clock
 expect {
-	clock1 = create({ hour: 24, minute: 0 })
-	clock2 = create({ hour: 0, minute: 0 })
+	clock1 = create({ hour: 24 })
+	clock2 = create({})
 	clock1 == clock2
 }
 
@@ -443,31 +443,31 @@ expect {
 # Can add max I64 values to a clock
 expect {
 	clock = create({ hour: 23, minute: 59 })
-	result = clock.add({ hour: 0, minute: 9223372036854775807 }).to_str()
+	result = clock.add({ minute: 9223372036854775807 }).to_str()
 	expected = "18:06"
 	result == expected
 }
 
 # Can add min I64 values to a clock
 expect {
 	clock = create({ hour: 23, minute: 59 })
-	result = clock.add({ hour: 0, minute: -9223372036854775808 }).to_str()
+	result = clock.add({ minute: -9223372036854775808 }).to_str()
 	expected = "05:51"
 	result == expected
 }
 
 # Can subtract max I64 values from a clock
 expect {
 	clock = create({ hour: 23, minute: 59 })
-	result = clock.subtract({ hour: 0, minute: 9223372036854775807 }).to_str()
+	result = clock.subtract({ minute: 9223372036854775807 }).to_str()
 	expected = "05:52"
 	result == expected
 }
 
 # Can subtract min I64 values from a clock
 expect {
 	clock = create({ hour: 23, minute: 59 })
-	result = clock.subtract({ hour: 0, minute: -9223372036854775808 }).to_str()
+	result = clock.subtract({ minute: -9223372036854775808 }).to_str()
 	expected = "18:07"
 	result == expected
 }

exercises/practice/killer-sudoku-helper/.meta/Example.roc

@@ -1,7 +1,7 @@
 KillerSudokuHelper :: {}.{
 	Combination : List(U8)
 
-	combinations : { sum : U8, size : U8, exclude : List(U8) } -> List(Combination)
+	combinations : { sum : U8, size : U8, exclude : List(U8) ?? [] } -> List(Combination)
 	combinations = |{ sum, size, exclude }| {
 		help = |target, digits| {
 			if target == 0 {

exercises/practice/killer-sudoku-helper/.meta/template.j2

@@ -5,7 +5,7 @@
 import {{ exercise | to_pascal }} exposing [combinations]
 
 {% macro to_cage(cage) -%}
-{ sum: {{ cage["sum"] }}, size: {{ cage["size"] }}, exclude: {{ cage["exclude"] | to_roc }} }
+{ sum: {{ cage["sum"] }}, size: {{ cage["size"] }}{% if cage["exclude"] %}, exclude: {{ cage["exclude"] | to_roc }}{% endif %} }
 {%- endmacro %}
 
 {% for supercase in cases %}

exercises/practice/killer-sudoku-helper/KillerSudokuHelper.roc

@@ -1,7 +1,7 @@
 KillerSudokuHelper :: {}.{
 	Combination : List(U8)
 
-	combinations : { sum : U8, size : U8, exclude : List(U8) } -> List(Combination)
+	combinations : { sum : U8, size : U8, exclude : List(U8) ?? [] } -> List(Combination)
 	combinations = |{ sum, size, exclude }| {
 		crash "Please implement the 'combinations' function"
 	}