dhall-lang · Nadrieril · Dec 27, 2019 · Dec 24, 2019 · Dec 24, 2019 · Dec 24, 2019
diff --git a/standard/dhall.abnf b/standard/dhall.abnf
@@ -223,9 +223,12 @@ label = ("`" quoted-label "`" / simple-label)
 ;    / !builtin label
 nonreserved-label = label
 
-; An any-label is allowed to be one of the reserved identifiers.
+; An any-label is allowed to be one of the reserved identifiers (but not a keyword).
 any-label = label
 
+; Allow specifically `Some` in record and union labels.
+any-label-or-some = any-label / Some
+
 
 ; Dhall's double-quoted strings are similar to JSON strings (RFC7159) except:
 ;
@@ -295,9 +298,9 @@ unbraced-escape =
 ;
 ; See the `valid-non-ascii` rule for the exact ranges that are not allowed
 braced-codepoint =
-      1*3HEXDIG ; %x000-FFF
+      ("1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9" / "A" / "B" / "C" / "D" / "E" / "F" / "10") unicode-suffix; (Planes 1-16)
     / unbraced-escape ; (Plane 0)
-    / ("1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9" / "A" / "B" / "C" / "D" / "E" / "F" / "10") unicode-suffix; (Planes 1-16)
+    / 1*3HEXDIG ; %x000-FFF
 
 ; Allow zero padding for braced codepoints
 braced-escape = *"0" braced-codepoint
@@ -838,7 +841,7 @@ selector-expression = primitive-expression *(whsp "." whsp selector)
 
 selector = any-label / labels / type-selector
 
-labels = "{" whsp [ any-label whsp *("," whsp any-label whsp) ] "}"
+labels = "{" whsp [ any-label-or-some whsp *("," whsp any-label-or-some whsp) ] "}"
 
 type-selector = "(" whsp expression whsp ")"
 ; NOTE: Backtrack when parsing the first three alternatives (i.e. the numeric
@@ -883,13 +886,13 @@ empty-record-literal = "="
 empty-record-type = ""
 
 non-empty-record-type-or-literal =
-    any-label whsp (non-empty-record-literal / non-empty-record-type)
+    any-label-or-some whsp (non-empty-record-literal / non-empty-record-type)
 
 non-empty-record-type = ":" whsp1 expression *(whsp "," whsp record-type-entry)
-record-type-entry = any-label whsp ":" whsp1 expression
+record-type-entry = any-label-or-some whsp ":" whsp1 expression
 
 non-empty-record-literal = "=" whsp expression *(whsp "," whsp record-literal-entry)
-record-literal-entry = any-label whsp "=" whsp expression
+record-literal-entry = any-label-or-some whsp "=" whsp expression
 
 union-type =
       non-empty-union-type
@@ -902,7 +905,7 @@ non-empty-union-type =
 
 ; x : Natural
 ; x
-union-type-entry = any-label [ whsp ":" whsp1 expression ]
+union-type-entry = any-label-or-some [ whsp ":" whsp1 expression ]
 
 non-empty-list-literal =
     "[" whsp [ "," whsp ] expression whsp *("," whsp expression whsp) "]"

diff --git a/tests/normalization/success/unit/NaturalBuildFoldFusionB.dhall b/tests/normalization/success/unit/NaturalBuildFoldFusionB.dhall
@@ -1 +1 @@
-λ(x : Natural) → Natural/fold x Natural (λ(n : Natural) → n + 1) 0
+λ(x : Natural) → Natural/fold x Natural (λ(x : Natural) → x + 1) 0
diff --git a/tests/parser/success/preferMissingNoSpacesB.dhallb b/tests/parser/success/preferMissingNoSpacesB.dhallb
diff --git a/tests/parser/success/preferMissingNoSpacesB.diag b/tests/parser/success/preferMissingNoSpacesB.diag
@@ -1 +1 @@
-[3, 9, [24, null, 0, 7], ["foo", 0]]
+["missing//foo", 0]
diff --git a/tests/parser/success/unit/RecordLitSomeA.dhall b/tests/parser/success/unit/RecordLitSomeA.dhall
@@ -0,0 +1 @@
+{ Some = 0 }
diff --git a/tests/parser/success/unit/RecordLitSomeB.dhallb b/tests/parser/success/unit/RecordLitSomeB.dhallb
diff --git a/tests/parser/success/unit/RecordLitSomeB.diag b/tests/parser/success/unit/RecordLitSomeB.diag
@@ -0,0 +1 @@
+[8, {"Some": [15, 0]}]
diff --git a/tests/parser/success/unit/SelectionSomeA.dhall b/tests/parser/success/unit/SelectionSomeA.dhall
@@ -0,0 +1 @@
+record.{ Some }
diff --git a/tests/parser/success/unit/SelectionSomeB.dhallb b/tests/parser/success/unit/SelectionSomeB.dhallb
diff --git a/tests/parser/success/unit/SelectionSomeB.diag b/tests/parser/success/unit/SelectionSomeB.diag
@@ -0,0 +1 @@
+[10, ["record", 0], "Some"]
diff --git a/tests/parser/success/unit/UnionTypeSomeA.dhall b/tests/parser/success/unit/UnionTypeSomeA.dhall
@@ -0,0 +1 @@
+< Some: Natural >
diff --git a/tests/parser/success/unit/UnionTypeSomeB.dhallb b/tests/parser/success/unit/UnionTypeSomeB.dhallb
@@ -0,0 +1 @@
+��dSomegNatural
diff --git a/tests/parser/success/unit/UnionTypeSomeB.diag b/tests/parser/success/unit/UnionTypeSomeB.diag
@@ -0,0 +1 @@
+[11, {"Some": "Natural"}]
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		λ(x : Natural) → Natural/fold x Natural (λ(n : Natural) → n + 1) 0
		λ(x : Natural) → Natural/fold x Natural (λ(x : Natural) → x + 1) 0
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		[3, 9, [24, null, 0, 7], ["foo", 0]]
		["missing//foo", 0]
Copy link Collaborator sjakobi Dec 24, 2019 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. That's not how the Haskell implementation parses it. Could you explain why this change is correct (and why the Haskell implementation is wrong)? Copy link Member Author Nadrieril Dec 24, 2019 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. I believe that both parses are technically allowed (i.e. the grammar is ambiguous). However, the text of the grammar states "prefer the first parse" and "prefer alternatives that parse as many repetitions as possible", which can be summed up as "parse greedily". Taking that into account, we get that when parsing `whatever// foo`, the whole of `whatever//` should be consumed as an identifier (since slashes are allowed in identifiers). Moreover I'm quite confident that this is the correct answer since I derived a parser directly from the abnf (taking into account greediness) and that's the output I got. Copy link Contributor Gabriella439 Dec 24, 2019 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. Yeah, my reading of the grammar is that this should be parsed as a single label Copy link Collaborator sjakobi Dec 25, 2019 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others. Learn more. Ok, seems like I just misread the grammar then! :) If it had turned out to be ambiguous, I would have suggested that we change that, but fortunately it doesn't seem to be the case. :)