Write a grammar! (#5)

I may be able to nerdsnipe @jackdotink into writing a parser, but in
exchange, I had to provide a grammar. So, here is an initial attempt at
a grammar, which will probably need a bunch of revisions.

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "sanguinello"
 version = "0.0.0"
-authors = ["aaron weiss <aweiss@hey.com>"]
+authors = ["ariel weiss <aweiss@hey.com>"]
 license = "BSD-2-Clause"
 edition = "2021"
 

GRAMMAR.md

@@ -0,0 +1,93 @@
+```
+binding = NAME [':' type]
+bindings = binding {',' binding}
+
+typebinding = 'type' NAME ['<' generictypeswithdefaults '>'] '=' type
+
+path = '@' [NAME]
+     | path '/' NAME
+import = 'import' binding '=' path
+export = 'export' bindings '=' exprs
+
+-- we could just pick one, i guess?
+fnword = 'fn' | 'function'
+
+block = {stat [';'] NEWLINE} [expr]
+stat = var '=' expr
+     | var compoundop expr
+     | 'while' expr 'do' block 'end'
+     | 'repeat' block 'until' expr
+     | 'for' bindings 'in' exprs 'do' block 'end'
+     | fnword funcname ['<' generictypes '>'] '(' [parameters] ')' [ ':' type] block 'end'
+     | 'module' binding 'do' properties 'end'
+     | 'local' bindings '=' exprs
+     | ['export'] typebinding
+     | import | export
+     | expr
+     | 'break' | 'continue'
+     | 'return' [expr]
+
+varroot = NAME | '(' expr ')'
+varsuffix = [':' NAME] '(' [exprs] ')' | '.' NAME | '[' expr ']'
+var = varroot {varsuffix}
+vars = var {',' var}
+
+expr = unop expr { binop expr }
+     | 'do' block 'end'
+     | 'if' expr 'then' block {'elseif' expr 'then' block} ['else' block] 'end'
+     | fnword ['<' generictypes '>'] '(' [parameters] ')' [ ':' type] block 'end'
+     | simpleexpr '::' type
+     | simpleexpr
+simpleexpr = var
+           | literal
+exprs = expr {separator expr} [separator]
+separator = ',' | ';'
+
+literal = NUMBER
+        | STRING
+        | 'nil'
+        | 'true'
+        | 'false'
+        | table
+        | array
+literals = literal {',' literal}
+
+array = '[' [exprs] ']'
+table = '{' [properties] '}'
+properties = property {separator property} [separator]
+property = '[' expr ']' '=' expr
+         | NAME '=' expr
+         | typebinding
+
+compoundop :: '+=' | '-=' | '*=' | '/=' | '//=' | '%=' | '^=' | '..='
+binop = '+' | '-' | '*' | '/' | '//' | '^' | '%' | '..' | '<' | '<=' | '>' | '>=' | '==' | '~=' | 'and' | 'or'
+unop = '-' | 'not' | '#'
+
+type = [simpletype {'?'}] {'|' simpletype {'?'}}
+     | [simpletype {'?'}] {'&' simpletype {'?'}}
+types = type {',' type}
+
+generictype = NAME
+generictypes = generictype {',' generictype}
+generictypewithdefault = generictype ['=' type]
+generictypeswithdefaults = generictypewithdefault {',' generictypeswithdefaults}
+
+tabletype = '{' [proplist] '}'
+propertytypes = propertytypeorindexer {separator propertytypeorindexer} [separator]
+propertytype = NAME ':' type
+indexer = '[' type ']' ':' type
+propertytypeorindexer = ['read' | 'write'] (propertytype | indexer)
+                      | 'type' NAME ['<' generictypes '>']
+proplist = propertytypeorindexer {',' propertytypeorindexer}
+
+singleton = STRING | 'true' | 'false'
+simpletype = 'nil'
+           | singleton
+           | 'boolean'
+           | 'string'
+           | 'number'
+           | '(' types ')'
+           | ['<' generictypes '>'] '(' types ')' '->' type
+           | tabletype
+           | '[' type ']'
+```

LICENSE

@@ -1,6 +1,6 @@
 BSD 2-Clause License
 
-Copyright (c) 2023, aaron weiss <aweiss@hey.com>
+Copyright (c) 2023-2025, ariel weiss <aweiss@hey.com>
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met: