Rebase latest changes in grammar

2 files changed, 75 insertions, 45 deletions

diff --git a/dhall_parser/src/dhall.abnf b/dhall_parser/src/dhall.abnf
index 51de689..f9ba91e 100644
--- a/dhall_parser/src/dhall.abnf
+++ b/dhall_parser/src/dhall.abnf
@@ -152,17 +152,34 @@ HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F"
 ; * as

 ; * using

 ; * merge

+; * missing

+; * Infinity

+; * Some

 simple-label-first-char = ALPHA / "_"

 simple-label-next-char = ALPHA / DIGIT / "-" / "/" / "_"

 simple-label = simple-label-first-char *simple-label-next-char

 

-quoted-label = 1*(ALPHA / DIGIT / "-" / "/" / "_" / ":" / "." / "$")

+quoted-label-char =

+      %x20-5F

+        ; %x60 = '`'

+    / %x61-7E

+

+quoted-label = 1*quoted-label-char

 

 ; NOTE: Dhall does not support Unicode labels, mainly to minimize the potential

 ; for code obfuscation

+; A label cannot not be any of the reserved identifiers for builtins (unless quoted).

+; Their list can be found in semantics.md. This is not enforced by the grammar but

+; should be checked by implementations. The only place where this restriction applies

+; is bound variables.

 label-raw = ("`" quoted-label "`" / simple-label)

 label = label-raw whitespace

 

+; An any-label is allowed to be one of the reserved identifiers.

+any-label = label

+any-label-raw = label-raw

+

+

 ; Dhall's double-quoted strings are equivalent to JSON strings except with

 ; support for string interpolation (and escaping string interpolation)

 ;

@@ -266,6 +283,7 @@ text-literal-raw = (double-quote-literal / single-quote-literal)
 ;

 ; If you don't feel like reading hex, these are all the same as the rule name,

 ; except without the '-raw' ending.

+; Keywords that should never be parsed as identifiers

 if-raw                = %x69.66

 then-raw              = %x74.68.65.6e

 else-raw              = %x65.6c.73.65

@@ -275,11 +293,14 @@ as-raw                = %x61.73
 using-raw             = %x75.73.69.6e.67

 merge-raw             = %x6d.65.72.67.65

 missing-raw           = %x6d.69.73.73.69.6e.67

+Infinity-raw          = %x49.6e.66.69.6e.69.74.79

+; Reserved identifiers, only needed for some special cases of parsing

 Optional-raw          = %x4f.70.74.69.6f.6e.61.6c

 Text-raw              = %x54.65.78.74

 List-raw              = %x4c.69.73.74

 Infinity-raw          = %x49.6e.66.69.6e.69.74.79

 NaN-raw               = %x4e.61.4e

+Some-raw              = %x53.6f.6d.65

 

 ; Whitespaced rules for reserved words, to be used when matching expressions

 if       = if-raw           nonempty-whitespace

@@ -290,38 +311,39 @@ in       = in-raw           nonempty-whitespace
 as       = as-raw           nonempty-whitespace

 using    = using-raw        nonempty-whitespace

 merge    = merge-raw        nonempty-whitespace

+Some     = Some-raw         nonempty-whitespace

 Optional = Optional-raw     whitespace

 Text     = Text-raw         whitespace

 List     = List-raw         whitespace

 

-equal             = "="  whitespace

-or                = "||" whitespace

-plus              = "+"  nonempty-whitespace  ; To disambiguate `f +2`

-text-append       = "++" whitespace

-list-append       = "#"  whitespace

-and               = "&&" whitespace

-times             = "*"  whitespace

-double-equal      = "==" whitespace

-not-equal         = "!=" whitespace

-dot               = "."  whitespace

-bar               = "|"  whitespace

-comma             = ","  whitespace

-at                = "@"  whitespace

-colon             = ":"  nonempty-whitespace  ; To disambiguate `env:VARIABLE` from type annotations

-import-alt        = "?"  nonempty-whitespace  ; To disambiguate `http://a/a?a`

-open-parens       = "("  whitespace

+

+equal         = "="  whitespace

+or            = "||" whitespace

+plus          = "+"  nonempty-whitespace  ; To disambiguate `f +2`

+text-append   = "++" whitespace

+list-append   = "#"  whitespace

+and           = "&&" whitespace

+times         = "*"  whitespace

+double-equal  = "==" whitespace

+not-equal     = "!=" whitespace

+dot           = "."  whitespace

+bar           = "|"  whitespace

+comma         = ","  whitespace

+at            = "@"  whitespace

+open-parens   = "("  whitespace

 close-parens-raw  = ")"

-close-parens      = ")"  whitespace

-open-brace        = "{"  whitespace

+close-parens  = ")"  whitespace

+open-brace    = "{"  whitespace

 close-brace-raw   = "}"

-close-brace       = "}"  whitespace

-open-bracket      = "["  whitespace

+close-brace   = "}"  whitespace

+open-bracket  = "["  whitespace

 close-bracket-raw = "]"

-close-bracket     = "]"  whitespace

-open-angle        = "<"  whitespace

+close-bracket = "]"  whitespace

+open-angle    = "<"  whitespace

 close-angle-raw   = ">"

-close-angle       = ">"  whitespace

-

+close-angle   = ">"  whitespace

+colon         = ":"  nonempty-whitespace  ; To disambiguate `env:VARIABLE` from type annotations

+import-alt    = "?"  nonempty-whitespace  ; To disambiguate `http://a/a?a`

 combine       = ( %x2227 / "/\"                ) whitespace

 combine-types = ( %x2A53 / "//\\"              ) whitespace

 prefer        = ( %x2AFD / "//"                ) whitespace

@@ -337,7 +359,9 @@ natural-literal-raw = 1*DIGIT
 

 integer-literal-raw = ( "+" / "-" ) natural-literal-raw

 

-identifier-raw = label-raw [ whitespace at natural-literal-raw ]

+; The implementation should recognize reserved names for builtins and treat them as special

+; values instead of variables.

+identifier-raw = any-label-raw [ whitespace at natural-literal-raw ]

 identifier = identifier-raw whitespace

 

 ; Printable characters other than " ()[]{}<>/\,"

@@ -406,8 +430,12 @@ absolute-path = path  ; Absolute path
 

 scheme = %x68.74.74.70 [ %x73 ]  ; "http" [ "s" ]

 

-; NOTE: This does not match the official grammar for a URI.  Specifically, this

-; replaces `path-abempty` with `path`

+; NOTE: This does not match the official grammar for a URI.  Specifically:

+;

+; * this replaces `path-abempty` with `path`, so an empty path is

+;   not valid

+; * this does not support fragment identifiers, which have no meaning within

+;   Dhall expressions and do not affect import resolution

 http-raw = scheme "://" authority path [ "?" query ]

 

 ; NOTE: Backtrack if parsing the optional user info prefix fails

@@ -544,8 +572,6 @@ import-raw = import-hashed-raw [ whitespace as Text-raw ]
 ; The exception is the rules ending in -raw, which should _not_ end in whitespace.

 ; This is important to avoid the need for sequential backtracking in application-expression.

 

-; An arbitrary dhall expression. Only use in a context where parentheses or

-; keywords prevent possible ambiguity. See also atomic-expression.

 expression =

     lambda-expression

     / ifthenelse-expression

@@ -580,14 +606,14 @@ arrow-expression = operator-expression arrow expression
 

 ; "merge e1 e2 : t"

 ; "merge e1 e2"

-merge-expression = merge atomic-expression atomic-expression [ colon application-expression ]

+merge-expression = merge import-expression import-expression [ colon application-expression ]

 

 ; "[]  : List     t"

 ; "[]  : Optional t"

 ; "[x] : Optional t"

 empty-list-or-optional = open-bracket (empty-collection / non-empty-optional)

-empty-collection = close-bracket colon (List / Optional) atomic-expression

-non-empty-optional = expression close-bracket colon Optional atomic-expression

+empty-collection = close-bracket colon (List / Optional) import-expression

+non-empty-optional = expression close-bracket colon Optional import-expression

 

 ; "x : t"

 annotated-expression = operator-expression [ colon expression ]

@@ -611,12 +637,11 @@ not-equal-expression     = application-expression   *(not-equal     application-
 ; Import expressions need to be separated by some whitespace, otherwise there

 ; would be ambiguity: `./ab` could be interpreted as "import the file `./ab`",

 ; or "apply the import `./a` to label `b`"

-; The -raw handling is important for greedy parsers, that can't do sequential backtracking.

-application-expression = atomic-expression-raw *(nonempty-whitespace atomic-expression-raw) whitespace

+application-expression =

+    import-expression-raw *(nonempty-whitespace import-expression-raw) whitespace

 

-; An expression that does not need to be surrounded by parentheses to disambiguate

-atomic-expression = atomic-expression-raw whitespace

-atomic-expression-raw =

+import-expression = import-expression-raw whitespace

+import-expression-raw =

       import-raw

     / selector-expression-raw

 

@@ -629,9 +654,9 @@ atomic-expression-raw =
 ; the function `foo` to the relative path `./bar`)

 selector-expression-raw = primitive-expression-raw *(whitespace dot selector-raw)

 

-selector-raw = label-raw / labels-raw

+selector-raw = any-label-raw / labels-raw

 

-labels-raw = open-brace [ label *(comma label) ] close-brace-raw

+labels-raw = open-brace [ any-label *(comma any-label) ] close-brace-raw

 

 

 primitive-expression-raw =

@@ -679,11 +704,11 @@ record-type-or-literal =
 empty-record-literal = equal

 empty-record-type = ""

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

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

+    any-label (non-empty-record-literal / non-empty-record-type)

 non-empty-record-type    = colon expression *(comma record-type-entry)

-record-type-entry = label colon expression

+record-type-entry = any-label colon expression

 non-empty-record-literal = equal expression *(comma record-literal-entry)

-record-literal-entry = label equal expression

+record-literal-entry = any-label equal expression

 

 ; "< Foo : Integer | Bar : Bool >"

 ; "< Foo : Integer | Bar = True >"

@@ -692,12 +717,12 @@ union-type-or-literal =
     / empty-union-type

 empty-union-type = ""

 non-empty-union-type-or-literal =

-    label

+    any-label

     ( equal expression union-type-entries

     / colon expression [ bar non-empty-union-type-or-literal ]

     )

 union-type-entries = *(bar union-type-entry)

-union-type-entry = label colon expression

+union-type-entry = any-label colon expression

 

 ; "[1, 2, 3]"

 ; `empty-list-or-optional` handles empty lists

diff --git a/dhall_parser/src/dhall.pest.visibility b/dhall_parser/src/dhall.pest.visibility
index 3d0a80c..da5217a 100644
--- a/dhall_parser/src/dhall.pest.visibility
+++ b/dhall_parser/src/dhall.pest.visibility
@@ -18,9 +18,12 @@ end_of_line
 # simple_label_next_char
 # simple_label_start
 simple_label
+# quoted_label_char
 quoted_label
 label_raw
 # label
+# any_label_raw
+# any_label
 double_quote_chunk
 double_quote_escaped
 double_quote_literal
@@ -151,6 +154,8 @@ not_equal_expression
 application_expression
 # atomic_expression
 # atomic_expression_raw
+# import_expression
+# import_expression_raw
 selector_expression_raw
 selector_raw
 labels_raw