From 15183aafe292695c54ae234a1210c08c8e3cd378 Mon Sep 17 00:00:00 2001 From: Théo Zimmermann Date: Fri, 13 Nov 2020 10:08:48 +0100 Subject: Move destructuring let syntax closer to its documentation. --- doc/sphinx/language/core/definitions.rst | 21 ++++++++++++--------- doc/sphinx/language/extensions/match.rst | 7 +++++++ 2 files changed, 19 insertions(+), 9 deletions(-) (limited to 'doc/sphinx') diff --git a/doc/sphinx/language/core/definitions.rst b/doc/sphinx/language/core/definitions.rst index 4ea3ea5e6d..79489c85f6 100644 --- a/doc/sphinx/language/core/definitions.rst +++ b/doc/sphinx/language/core/definitions.rst @@ -13,15 +13,18 @@ Let-in definitions .. prodn:: term_let ::= let @name {? : @type } := @term in @term | let @name {+ @binder } {? : @type } := @term in @term - | let ( {*, @name } ) {? {? as @name } return @term100 } := @term in @term - | let ' @pattern := @term {? return @term100 } in @term - | let ' @pattern in @pattern := @term return @term100 in @term - -:n:`let @ident := @term in @term’` -denotes the local binding of :n:`@term` to the variable -:n:`@ident` in :n:`@term`’. There is a syntactic sugar for let-in -definition of functions: :n:`let @ident {+ @binder} := @term in @term’` -stands for :n:`let @ident := fun {+ @binder} => @term in @term’`. + | @destructuring_let + +:n:`let @ident := @term__1 in @term__2` represents the local binding of +the variable :n:`@ident` to the value :n:`@term__1` in :n:`@term__2`. + +:n:`let @ident {+ @binder} := @term__1 in @term__2` is an abbreviation +for :n:`let @ident := fun {+ @binder} => @term__1 in @term__2`. + +.. seealso:: + + Extensions of the `let ... in ...` syntax are described in + :ref:`irrefutable-patterns`. .. index:: single: ... : ... (type cast) diff --git a/doc/sphinx/language/extensions/match.rst b/doc/sphinx/language/extensions/match.rst index 23389eba3b..8e62c2af13 100644 --- a/doc/sphinx/language/extensions/match.rst +++ b/doc/sphinx/language/extensions/match.rst @@ -86,6 +86,13 @@ Pattern-matching on terms inhabiting inductive type having only one constructor can be alternatively written using :g:`let … in …` constructions. There are two variants of them. +.. insertprodn destructuring_let destructuring_let + +.. prodn:: + destructuring_let ::= let ( {*, @name } ) {? {? as @name } return @term100 } := @term in @term + | let ' @pattern := @term {? return @term100 } in @term + | let ' @pattern in @pattern := @term return @term100 in @term + First destructuring let syntax ++++++++++++++++++++++++++++++ -- cgit v1.2.3