Grammar (implemented subset)

1program       ::= (import | import-list | import-default | import-namespace)* declaration* EOF ;
2import        ::= "import" STRING "as" IDENT ";" ;
3import-list   ::= "import" "{" import-specifier ("," import-specifier)* "}" "from" STRING ";" ;
4import-specifier ::= IDENT ("as" IDENT)? ;
5import-default   ::= "import" IDENT "from" STRING ";" ;
6import-namespace ::= "import" "*" "as" IDENT "from" STRING ";" ;
7declaration   ::= "export"? modifiers* ( variable | function | class | interface ) | statement ;
8export-list   ::= "export" "{" IDENT ("," IDENT)* "}" ";" ;
9export-default-var ::= "export" "default" (variable | function | class | interface) ;
10variable      ::= ("var" | "const") IDENT (":" type)? ("=" expression)? ";" ;
11function      ::= "fn" IDENT "(" parameters? ")" (":" type)? block ;
12parameters    ::= IDENT ":" type ("," IDENT ":" type)* ;
13class         ::= "class" IDENT ("extends" IDENT)? ("implements" type-arg ("," type-arg)*)? "{" class-member* "}" ;
14class-member  ::= modifiers* ("init" | "fn" IDENT) "(" parameters? ")" (":" type)? (block | ";")
15                | modifiers* IDENT ":" type ("=" expression)? ";" ;
16interface     ::= "intf" IDENT ("<" type-param ("," type-param)* ">")?
17                  ("extends" type-arg ("," type-arg)*)? "{" interface-member* "}" ;
18interface-member ::= "fn" IDENT "(" parameters? ")" ":" type ";"
19                   | IDENT ":" type ";" | IDENT "?" ":" type ";"
20                   | "[" IDENT ":" type "]" ":" type ";"        (* index signature *)
21                   | "(" parameters? ")" ":" type ";"          (* call signature *)
22                   | IDENT "(" parameters? ")" ":" type ";" ;  (* method *)
23type-param    ::= IDENT ;
24type          ::= IDENT ("<" type ("," type)* ">")? ("?")? ("|" type)* ;
25switch        ::= "switch" "(" expression ")" "{" ( "case" expression ":" block | "default" ":" block )+ "}" ;
26await-expr    ::= "await" unary ;