From 72ad56209fe10e3120c19ca5b820ff267423ab1d Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sat, 11 Apr 2020 15:41:21 +0100
Subject: spec: fix precedence of `===` and `with`

---
 dhall/src/syntax/text/dhall.abnf | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

(limited to 'dhall/src/syntax/text/dhall.abnf')

diff --git a/dhall/src/syntax/text/dhall.abnf b/dhall/src/syntax/text/dhall.abnf
index 1c3a980..861f7b3 100644
--- a/dhall/src/syntax/text/dhall.abnf
+++ b/dhall/src/syntax/text/dhall.abnf
@@ -757,6 +757,11 @@ expression =
     ; NOTE: Backtrack if parsing this alternative fails
     / operator-expression whsp arrow whsp expression
     
+    ; "a with x = b"
+    ;
+    ; NOTE: Backtrack if parsing this alternative fails
+    / with-expression
+    
     ; "merge e1 e2 : t"
     ;
     ; NOTE: Backtrack if parsing this alternative fails since we can't tell
@@ -792,9 +797,16 @@ let-binding = let whsp1 nonreserved-label whsp [ ":" whsp1 expression whsp ] "="
 empty-list-literal =
     "[" whsp [ "," whsp ] "]" whsp ":" whsp1 application-expression
 
-operator-expression = import-alt-expression
+with-expression =
+    import-expression 1*(whsp1 with whsp1 with-clause)
+
+with-clause =
+    any-label-or-some *(whsp "." whsp any-label-or-some) whsp "=" whsp operator-expression
+
+operator-expression = equivalent-expression
 
 ; Nonempty-whitespace to disambiguate `http://a/a?a`
+equivalent-expression    = import-alt-expression    *(whsp equivalent whsp import-alt-expression)
 import-alt-expression    = or-expression            *(whsp "?" whsp1 or-expression)
 or-expression            = plus-expression          *(whsp "||" whsp plus-expression)
 ; Nonempty-whitespace to disambiguate `f +2`
@@ -807,13 +819,7 @@ prefer-expression        = combine-types-expression *(whsp prefer whsp combine-t
 combine-types-expression = times-expression         *(whsp combine-types whsp times-expression)
 times-expression         = equal-expression         *(whsp "*" whsp equal-expression)
 equal-expression         = not-equal-expression     *(whsp "==" whsp not-equal-expression)
-not-equal-expression     = equivalent-expression    *(whsp "!=" whsp equivalent-expression)
-equivalent-expression    = with-expression          *(whsp equivalent whsp with-expression)
-
-with-expression = application-expression *(whsp1 with whsp1 with-clause)
-
-with-clause =
-    any-label-or-some *(whsp "." whsp any-label-or-some) whsp "=" whsp application-expression
+not-equal-expression     = application-expression   *(whsp "!=" whsp application-expression)
 
 
 ; Import expressions need to be separated by some whitespace, otherwise there
-- 
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