diff options
| -rw-r--r-- | dhall_parser/src/dhall.abnf | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/dhall_parser/src/dhall.abnf b/dhall_parser/src/dhall.abnf index 52d5b91..9456036 100644 --- a/dhall_parser/src/dhall.abnf +++ b/dhall_parser/src/dhall.abnf @@ -620,7 +620,8 @@ selector = any-label / labels labels = "{" whsp [ any-label whsp *("," whsp any-label whsp) ] "}"
-
+; NOTE: Backtrack when parsing the first three alternatives (i.e. the numeric
+; literals). This is because they share leading characters in common
primitive-expression =
; "2.0"
double-literal
@@ -634,27 +635,27 @@ primitive-expression = ; '"ABC"'
/ text-literal
+ / "{" whsp record-type-or-literal whsp "}"
+ / "<" whsp union-type-or-literal whsp ">"
+ / non-empty-list-literal
; "x"
; "x@2"
/ identifier
- / "{" whsp record-type-or-literal "}"
- / "<" whsp union-type-or-literal ">"
- / non-empty-list-literal
- / parenthesized-expression
+ / "(" whsp expression whsp ")"
record-type-or-literal =
empty-record-literal
/ non-empty-record-type-or-literal
/ empty-record-type
-empty-record-literal = "=" whsp
+empty-record-literal = "="
empty-record-type = ""
non-empty-record-type-or-literal =
any-label 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 whsp
-non-empty-record-literal = "=" whsp expression whsp *("," whsp record-literal-entry)
-record-literal-entry = any-label whsp "=" whsp expression whsp
+non-empty-record-type = ":" whsp1 expression *(whsp "," whsp record-type-entry)
+record-type-entry = any-label whsp ":" whsp1 expression
+non-empty-record-literal = "=" whsp expression *(whsp "," whsp record-literal-entry)
+record-literal-entry = any-label whsp "=" whsp expression
; "< Foo : Integer | Bar : Bool >"
; "< Foo : Integer | Bar = True >"
@@ -666,19 +667,16 @@ empty-union-type = "" non-empty-union-type-or-literal =
any-label whsp
- ( "=" whsp expression whsp union-type-entries
- / ":" whsp1 expression whsp [ "|" whsp non-empty-union-type-or-literal ]
+ ( "=" whsp expression union-type-entries
+ / ":" whsp1 expression [ whsp "|" whsp non-empty-union-type-or-literal ]
)
-union-type-entries = *("|" whsp union-type-entry)
-union-type-entry = any-label whsp ":" whsp1 expression whsp
+union-type-entries = *(whsp "|" whsp union-type-entry)
+union-type-entry = any-label whsp ":" whsp1 expression
; "[1, 2, 3]"
; `empty-list-or-optional` handles empty lists
non-empty-list-literal = "[" whsp expression whsp *("," whsp expression whsp) "]"
-; "( e )"
-parenthesized-expression = "(" whsp expression whsp ")"
-
; This just adds surrounding whitespace for the top-level of the program
complete-expression = whsp expression whsp
|