From a342f45f820e28638e4a73a7b3a577ebf2396b0d Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Thu, 4 Apr 2019 18:48:42 +0200
Subject: Factor back in some rule branches

---
 dhall_parser/src/dhall.abnf            | 64 +++++++++++++++-------------------
 dhall_parser/src/dhall.pest.visibility | 22 ++++--------
 2 files changed, 36 insertions(+), 50 deletions(-)

(limited to 'dhall_parser/src')

diff --git a/dhall_parser/src/dhall.abnf b/dhall_parser/src/dhall.abnf
index 8964f44..2fad4d4 100644
--- a/dhall_parser/src/dhall.abnf
+++ b/dhall_parser/src/dhall.abnf
@@ -529,52 +529,46 @@ import = import-hashed [ whsp as whsp1 Text ]
 ; This is important to avoid the need for sequential backtracking in application-expression.
 
 expression =
-    lambda-expression
-    / ifthenelse-expression
-    / let-expression
-    / forall-expression
+    ; "\(x : a) -> b"
+      lambda whsp "(" whsp nonreserved-label whsp ":" whsp1 expression whsp ")" whsp arrow whsp expression
+    
+    ; "if a then b else c"
+    / if whsp1 expression whsp then whsp1 expression whsp else whsp1 expression
+    
+    ; "let x : t = e1 in e2"
+    ; "let x     = e1 in e2"
+    ; "let x = e1 let y = e2 in e3"
+    / 1*let-binding in whsp1 expression
+    
+    ; "forall (x : a) -> b"
+    / forall whsp "(" whsp nonreserved-label whsp ":" whsp1 expression whsp ")" whsp arrow whsp expression
+    
+    ; "a -> b"
     ; NOTE: Backtrack if parsing this alternative fails
-    / arrow-expression
-    / merge-expression
+    / operator-expression whsp arrow whsp expression
+    
+    ; "merge e1 e2 : t"
+    ; "merge e1 e2"
+    / merge whsp1 import-expression whsp import-expression [ whsp ":" whsp1 application-expression ]
+    
+    ; "[]  : List     t"
+    ; "[]  : Optional t"
+    ; "[x] : Optional t"
     ; NOTE: Backtrack if parsing this alternative fails since we can't tell
     ; from the opening bracket whether or not this will be an empty list or
     ; a non-empty list
-    / empty-list-or-optional
+    / "[" whsp (empty-collection / non-empty-optional)
+    
+    ; "x : t"
     / annotated-expression
 
-; "\(x : a) -> b"
-lambda-expression = lambda whsp "(" whsp nonreserved-label whsp ":" whsp1 expression whsp ")" whsp arrow whsp expression
-
-; "if a then b else c"
-ifthenelse-expression = if whsp1 expression whsp then whsp1 expression whsp else whsp1 expression
+; "x : t"
+annotated-expression = operator-expression [ whsp ":" whsp1 expression ]
 
-; "let x : t = e1 in e2"
-; "let x     = e1 in e2"
-; "let x = e1 let y = e2 in e3"
-let-expression = 1*let-binding in whsp1 expression
 let-binding = let whsp1 nonreserved-label whsp [ ":" whsp1 expression whsp ] "=" whsp expression whsp
-
-; "forall (x : a) -> b"
-forall-expression = forall whsp "(" whsp nonreserved-label whsp ":" whsp1 expression whsp ")" whsp arrow whsp expression
-
-; "a -> b"
-arrow-expression = operator-expression whsp arrow whsp expression
-
-; "merge e1 e2 : t"
-; "merge e1 e2"
-merge-expression = merge whsp1 import-expression whsp import-expression [ whsp ":" whsp1 application-expression ]
-
-; "[]  : List     t"
-; "[]  : Optional t"
-; "[x] : Optional t"
-empty-list-or-optional = "[" whsp (empty-collection / non-empty-optional)
 empty-collection = "]" whsp ":" whsp1 (List / Optional) whsp import-expression
 non-empty-optional = expression whsp "]" whsp ":" whsp1 Optional whsp import-expression
 
-; "x : t"
-annotated-expression = operator-expression [ whsp ":" whsp1 expression ]
-
-
 operator-expression = import-alt-expression
 
 ; Nonempty-whitespace to disambiguate `http://a/a?a`
diff --git a/dhall_parser/src/dhall.pest.visibility b/dhall_parser/src/dhall.pest.visibility
index e95cd32..ac3ea30 100644
--- a/dhall_parser/src/dhall.pest.visibility
+++ b/dhall_parser/src/dhall.pest.visibility
@@ -34,16 +34,15 @@ single_quote_literal
 # in
 # as
 # using
-# merge
 missing
-# if_
+if_
 # then
 # else_
 # let_
-# in_
+in_
 # as_
 # using
-# merge
+merge
 # Infinity
 Optional
 Text
@@ -78,9 +77,9 @@ List
 # combine
 # combine_types
 # prefer
-# lambda
-# forall
-# arrow
+lambda
+forall
+arrow
 # exponent
 double_literal
 natural_literal
@@ -120,14 +119,7 @@ import_type
 hash
 import_hashed
 import
-# expression
-lambda_expression
-ifthenelse_expression
-let_expression
-forall_expression
-arrow_expression
-merge_expression
-# empty_list_or_optional
+expression
 empty_collection
 non_empty_optional
 annotated_expression
-- 
cgit v1.2.3