spec: allow trailing delimiters

27 files changed, 52 insertions, 6 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2a63eb7..d9fa944 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 #### [Unreleased]
 
+- Allow trailing delimiters in records, lists, etc.
 - BREAKING CHANGE: Support Dhall v17.0.0
 
     See https://github.com/dhall-lang/dhall-lang/releases/tag/v16.0.0 and
diff --git a/dhall-lang b/dhall-lang
-Subproject f035ea1947d9392bcedbe7f8c563f33559370ef
+Subproject 0c899ab31fdb857f535fe9f5b37f981271824a6
diff --git a/dhall/src/syntax/text/dhall.abnf b/dhall/src/syntax/text/dhall.abnf
index 37ec43b..2d487f5 100644
--- a/dhall/src/syntax/text/dhall.abnf
+++ b/dhall/src/syntax/text/dhall.abnf
@@ -853,7 +853,8 @@ selector-expression = primitive-expression *(whsp "." whsp selector)
 

 selector = any-label / labels / type-selector

 

-labels = "{" whsp [ any-label-or-some whsp *("," whsp any-label-or-some whsp) ] "}"

+labels =

+    "{" whsp [ "," whsp ] [ any-label-or-some whsp *("," whsp any-label-or-some whsp) [ "," whsp ] ] "}"

 

 type-selector = "(" whsp expression whsp ")"

 ; NOTE: Backtrack when parsing the first three alternatives (i.e. the numeric

@@ -894,18 +895,18 @@ record-type-or-literal =
       empty-record-literal

     / [non-empty-record-type-or-literal]

 

-empty-record-literal = "="

+empty-record-literal = "=" [ whsp "," ]

 

 non-empty-record-type-or-literal =

     (non-empty-record-type / non-empty-record-literal)

 

 non-empty-record-type =

-    record-type-entry *(whsp "," whsp record-type-entry)

+    record-type-entry *(whsp "," whsp record-type-entry) [ whsp "," ]

 

 record-type-entry = any-label-or-some whsp ":" whsp1 expression

 

 non-empty-record-literal =

-    record-literal-entry *(whsp "," whsp record-literal-entry)

+    record-literal-entry *(whsp "," whsp record-literal-entry) [ whsp "," ]

 

 ; If the `record-literal-normal-entry` is absent, that represents a punned

 ; record entry, such as in `{ x }`, which is a short-hand for `{ x = x }`

@@ -918,7 +919,7 @@ record-literal-normal-entry =
 ; If the `union-type-entry` is absent, that represents an empty union

 ; alternative, such as in `< Heads | Tails >`

 union-type =

-    [union-type-entry *(whsp "|" whsp union-type-entry)]

+    [union-type-entry *(whsp "|" whsp union-type-entry) [ whsp "|" ]]

 

 ; x : Natural

 ; x

@@ -926,7 +927,7 @@ union-type-entry = any-label-or-some [ whsp ":" whsp1 expression ]
 

 

 non-empty-list-literal =

-    "[" whsp [ "," whsp ] expression whsp *("," whsp expression whsp) "]"

+    "[" whsp [ "," whsp ] expression whsp *("," whsp expression whsp) [ "," whsp ] "]"

 

 ; This just adds surrounding whitespace for the top-level of the program

 complete-expression = whsp expression whsp

diff --git a/dhall/tests/parser/failure/unit/ListLitTwoCommas.txt b/dhall/tests/parser/failure/unit/ListLitTwoCommas.txt
new file mode 100644
index 0000000..1cdfed5
--- /dev/null
+++ b/dhall/tests/parser/failure/unit/ListLitTwoCommas.txt
@@ -0,0 +1,6 @@
+ --> 1:4
+  |
+1 | [ ,, ]␊
+  |    ^---
+  |
+  = expected expression
diff --git a/dhall/tests/parser/failure/unit/ProjectionTwoCommas.txt b/dhall/tests/parser/failure/unit/ProjectionTwoCommas.txt
new file mode 100644
index 0000000..1585703
--- /dev/null
+++ b/dhall/tests/parser/failure/unit/ProjectionTwoCommas.txt
@@ -0,0 +1,6 @@
+ --> 1:8
+  |
+1 | foo.{ ,, }␊
+  |        ^---
+  |
+  = expected any_label_or_some
diff --git a/dhall/tests/parser/failure/unit/RecordTwoCommas.txt b/dhall/tests/parser/failure/unit/RecordTwoCommas.txt
new file mode 100644
index 0000000..3828d4b
--- /dev/null
+++ b/dhall/tests/parser/failure/unit/RecordTwoCommas.txt
@@ -0,0 +1,6 @@
+ --> 1:4
+  |
+1 | { ,, }␊
+  |    ^---
+  |
+  = expected any_label_or_some or empty_record_literal
diff --git a/dhall/tests/parser/failure/unit/UnionTypeTwoDelims.txt b/dhall/tests/parser/failure/unit/UnionTypeTwoDelims.txt
new file mode 100644
index 0000000..c4fa37e
--- /dev/null
+++ b/dhall/tests/parser/failure/unit/UnionTypeTwoDelims.txt
@@ -0,0 +1,6 @@
+ --> 1:4
+  |
+1 | < || >␊
+  |    ^---
+  |
+  = expected any_label_or_some
diff --git a/dhall/tests/parser/success/unit/ListLitEmptyCommaB.txt b/dhall/tests/parser/success/unit/ListLitEmptyCommaB.txt
new file mode 100644
index 0000000..3b99552
--- /dev/null
+++ b/dhall/tests/parser/success/unit/ListLitEmptyCommaB.txt
@@ -0,0 +1 @@
+[] : List Bool
diff --git a/dhall/tests/parser/success/unit/ListLitLeadingCommaB.txt b/dhall/tests/parser/success/unit/ListLitLeadingCommaB.txt
new file mode 100644
index 0000000..5ed6f26
--- /dev/null
+++ b/dhall/tests/parser/success/unit/ListLitLeadingCommaB.txt
@@ -0,0 +1 @@
+[x, y]
diff --git a/dhall/tests/parser/success/unit/ListLitTrailingAndLeadingCommasB.txt b/dhall/tests/parser/success/unit/ListLitTrailingAndLeadingCommasB.txt
new file mode 100644
index 0000000..5ed6f26
--- /dev/null
+++ b/dhall/tests/parser/success/unit/ListLitTrailingAndLeadingCommasB.txt
@@ -0,0 +1 @@
+[x, y]
diff --git a/dhall/tests/parser/success/unit/ListLitTrailingCommaB.txt b/dhall/tests/parser/success/unit/ListLitTrailingCommaB.txt
new file mode 100644
index 0000000..5ed6f26
--- /dev/null
+++ b/dhall/tests/parser/success/unit/ListLitTrailingCommaB.txt
@@ -0,0 +1 @@
+[x, y]
diff --git a/dhall/tests/parser/success/unit/ProjectionLeadingCommaB.txt b/dhall/tests/parser/success/unit/ProjectionLeadingCommaB.txt
new file mode 100644
index 0000000..519da8c
--- /dev/null
+++ b/dhall/tests/parser/success/unit/ProjectionLeadingCommaB.txt
@@ -0,0 +1 @@
+foo.{ x, y }
diff --git a/dhall/tests/parser/success/unit/ProjectionTrailingAndLeadingCommasB.txt b/dhall/tests/parser/success/unit/ProjectionTrailingAndLeadingCommasB.txt
new file mode 100644
index 0000000..519da8c
--- /dev/null
+++ b/dhall/tests/parser/success/unit/ProjectionTrailingAndLeadingCommasB.txt
@@ -0,0 +1 @@
+foo.{ x, y }
diff --git a/dhall/tests/parser/success/unit/ProjectionTrailingCommaB.txt b/dhall/tests/parser/success/unit/ProjectionTrailingCommaB.txt
new file mode 100644
index 0000000..519da8c
--- /dev/null
+++ b/dhall/tests/parser/success/unit/ProjectionTrailingCommaB.txt
@@ -0,0 +1 @@
+foo.{ x, y }
diff --git a/dhall/tests/parser/success/unit/RecordLitEmptyLeadingCommaB.txt b/dhall/tests/parser/success/unit/RecordLitEmptyLeadingCommaB.txt
new file mode 100644
index 0000000..339130f
--- /dev/null
+++ b/dhall/tests/parser/success/unit/RecordLitEmptyLeadingCommaB.txt
@@ -0,0 +1 @@
+{=}
diff --git a/dhall/tests/parser/success/unit/RecordLitEmptyTrailingCommaB.txt b/dhall/tests/parser/success/unit/RecordLitEmptyTrailingCommaB.txt
new file mode 100644
index 0000000..339130f
--- /dev/null
+++ b/dhall/tests/parser/success/unit/RecordLitEmptyTrailingCommaB.txt
@@ -0,0 +1 @@
+{=}
diff --git a/dhall/tests/parser/success/unit/RecordLitLeadingCommaB.txt b/dhall/tests/parser/success/unit/RecordLitLeadingCommaB.txt
new file mode 100644
index 0000000..325db4f
--- /dev/null
+++ b/dhall/tests/parser/success/unit/RecordLitLeadingCommaB.txt
@@ -0,0 +1 @@
+{ x = 0, y = 1 }
diff --git a/dhall/tests/parser/success/unit/RecordLitTrailingAndLeadingCommasB.txt b/dhall/tests/parser/success/unit/RecordLitTrailingAndLeadingCommasB.txt
new file mode 100644
index 0000000..325db4f
--- /dev/null
+++ b/dhall/tests/parser/success/unit/RecordLitTrailingAndLeadingCommasB.txt
@@ -0,0 +1 @@
+{ x = 0, y = 1 }
diff --git a/dhall/tests/parser/success/unit/RecordLitTrailingCommaB.txt b/dhall/tests/parser/success/unit/RecordLitTrailingCommaB.txt
new file mode 100644
index 0000000..325db4f
--- /dev/null
+++ b/dhall/tests/parser/success/unit/RecordLitTrailingCommaB.txt
@@ -0,0 +1 @@
+{ x = 0, y = 1 }
diff --git a/dhall/tests/parser/success/unit/RecordTypeEmptyCommaB.txt b/dhall/tests/parser/success/unit/RecordTypeEmptyCommaB.txt
new file mode 100644
index 0000000..0967ef4
--- /dev/null
+++ b/dhall/tests/parser/success/unit/RecordTypeEmptyCommaB.txt
@@ -0,0 +1 @@
+{}
diff --git a/dhall/tests/parser/success/unit/RecordTypeLeadingCommaB.txt b/dhall/tests/parser/success/unit/RecordTypeLeadingCommaB.txt
new file mode 100644
index 0000000..b88d0ae
--- /dev/null
+++ b/dhall/tests/parser/success/unit/RecordTypeLeadingCommaB.txt
@@ -0,0 +1 @@
+{ x : T, y : U }
diff --git a/dhall/tests/parser/success/unit/RecordTypeTrailingAndLeadingCommasB.txt b/dhall/tests/parser/success/unit/RecordTypeTrailingAndLeadingCommasB.txt
new file mode 100644
index 0000000..b88d0ae
--- /dev/null
+++ b/dhall/tests/parser/success/unit/RecordTypeTrailingAndLeadingCommasB.txt
@@ -0,0 +1 @@
+{ x : T, y : U }
diff --git a/dhall/tests/parser/success/unit/RecordTypeTrailingCommaB.txt b/dhall/tests/parser/success/unit/RecordTypeTrailingCommaB.txt
new file mode 100644
index 0000000..b88d0ae
--- /dev/null
+++ b/dhall/tests/parser/success/unit/RecordTypeTrailingCommaB.txt
@@ -0,0 +1 @@
+{ x : T, y : U }
diff --git a/dhall/tests/parser/success/unit/UnionTypeEmptyDelimB.txt b/dhall/tests/parser/success/unit/UnionTypeEmptyDelimB.txt
new file mode 100644
index 0000000..c677118
--- /dev/null
+++ b/dhall/tests/parser/success/unit/UnionTypeEmptyDelimB.txt
@@ -0,0 +1 @@
+<  >
diff --git a/dhall/tests/parser/success/unit/UnionTypeLeadingDelimB.txt b/dhall/tests/parser/success/unit/UnionTypeLeadingDelimB.txt
new file mode 100644
index 0000000..0f942c8
--- /dev/null
+++ b/dhall/tests/parser/success/unit/UnionTypeLeadingDelimB.txt
@@ -0,0 +1 @@
+< x: T | y: U >
diff --git a/dhall/tests/parser/success/unit/UnionTypeTrailingAndLeadingDelimsB.txt b/dhall/tests/parser/success/unit/UnionTypeTrailingAndLeadingDelimsB.txt
new file mode 100644
index 0000000..0f942c8
--- /dev/null
+++ b/dhall/tests/parser/success/unit/UnionTypeTrailingAndLeadingDelimsB.txt
@@ -0,0 +1 @@
+< x: T | y: U >
diff --git a/dhall/tests/parser/success/unit/UnionTypeTrailingDelimB.txt b/dhall/tests/parser/success/unit/UnionTypeTrailingDelimB.txt
new file mode 100644
index 0000000..0f942c8
--- /dev/null
+++ b/dhall/tests/parser/success/unit/UnionTypeTrailingDelimB.txt
@@ -0,0 +1 @@
+< x: T | y: U >