From 92ad2bc118809bfd4bc8d4286bef5fbf2fd551d5 Mon Sep 17 00:00:00 2001
From: Emi Simpson <emi@alchemi.dev>
Date: Thu, 10 Mar 2022 20:28:55 -0500
Subject: [PATCH] Added an EBNF grammar

---
 grammar.ebnf | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 grammar.ebnf

diff --git a/grammar.ebnf b/grammar.ebnf
new file mode 100644
index 0000000..eec73ca
--- /dev/null
+++ b/grammar.ebnf
@@ -0,0 +1,69 @@
+<program>             ::= { DeclarationStart <declaration> }
+
+<declaration>         ::= Type Symbol [ <typeargs> ] { Symbol } Assign <variant_decl> { VBar <variant_decl> }
+                        | Struct Symbol { Symbol } Assign { <def_field> }
+                        | Trait Symbol [ <typeargs> ] [ On <composite_type> ] Needs { <def_field> }
+                        | Impl Symbol [ <typerags> ] On <composite_type> Colon <impl> { <impl> }
+                        | Symbol <def>
+
+<variant_declaration> ::= Symbol { <grouped_type> }
+
+<full_type>           ::= <composite_type> [ { Comma <composite_type> } Aro <full_type> ]
+
+<composite_type>      ::= <simple_type> { <grouped_type> }
+
+<grouped_type>        ::= <simple_type>
+                       |  OpenParen <full_type> CloseParen
+
+<simple_type>         ::= Symbol  [ OpenSquareBracket <domain> CloseSquareBracket ]
+
+<domain>              ::= Int Range Int
+                       |  Int
+
+<def_field>           ::= Dot Symbol Colon <full_type>
+
+<typeargs>            ::= OpenSouareBracket <typearg> { , <typearg> } CloseSquareBracket
+<typearg>             ::= Symbol Colon <full_type>
+
+<impl>                ::= Dot Symbol { Symbol } Assign <expr>
+
+<def>                 ::= Colon <full_type>
+                       |  { Symbol } Assign <expr>
+
+
+
+
+<expr>        ::= <tightexpr> { <tightexpr> }
+               |  If <expr> <ifblock>
+               |  <let> { <let> } In <expr>
+               |  <infix_expr>
+<tightexpr>   ::= Literal
+               |  { <multisymbol> }
+               |  OpenParen <expr> CloseParen
+
+<multisymbol> ::= Symbol { Dot Symbol }
+
+<let>         ::= Let Symbol Assign <expr>
+
+<ifblock>     ::= Is <case> { Comma <case> } [ Comma ]
+               |  Then  <expr> Else <expr>
+
+<case>        ::= <binding_pattern> Aro <expr>
+
+
+<infix_expr>        ::= <infix_rank2_expr> { <infix_rank1_op> <infix_rank2_expr> }
+<infix_rank2_expr>  ::= <infix_rank3_expr> { <infix_rank2_op> <infix_rank3_expr> }
+<infix_rank3_expr>  ::= <infix_rank4_expr> { <infix_rank3_op> <infix_rank4_expr> }
+<infix_rank4_expr>  ::= <infix_rank5_expr> { <infix_rank4_op> <infix_rank5_expr> }
+<infix_rank5_expr>  ::= <tightexpr>        { <infix_rank5_op> <tightexpr>        }
+<infix_rank1_op>    ::= Mult | Div | Mod
+<infix_rank2_op>    ::= Add | Sub
+<infix_rank3_op>    ::= Eq | NEq | LessThan | GreaterThan
+<infix_rank4_op>    ::= LAnd
+<infix_rank5_op>    ::= LOr
+
+<binding_pattern> ::= Symbol <bp_innards>
+                    | Literal
+<bp_innards>      ::= { <bp_field> }
+                    | { <binding_pattern }
+<bp_field>        ::= Dot Symbol Assign <binding_pattern>