program: decl*

?decl: iface
	| node
	| func

sep_trail{item, punc}: item (punc item)? punc?

func: "fn" ident "(" ")" ("->" ty) "{" "}"

iface: "iface" ident "{" sep_trail{iface_field, ","} "}"
iface_field: ident ":" ident

iface_ref: ident
iface_refs: iface_ref*
node: "node" ident ":" iface_refs "{" variants "}"
variants: variant*
variant: prod "=>" "{" equations "}"
prod: sym*
sym: sym_rename
	| STRING
sym_rename: "<" ident ":" node_ref ">"
node_ref: node_ref_name
	| STRING
node_ref_name: ident
equations: equation_*
equation_: equation ";"
// TODO: the left side should really be a separate type
// called lvalue, and should NOT include literals
equation: expr "=" expr

expr: expr_dot
	| expr_add
	| expr_mul
	| expr_call
	| expr_name
expr_dot: expr "." expr
expr_add: expr "+" expr
expr_mul: expr "*" expr
expr_call: expr "(" args ")"
expr_name: ident
args: sep_trail{expr, ","}

ty: ident

ident: IDENT
COMMENT: /\/\/[^\n]*/
IDENT: /([a-zA-Z][a-zA-Z0-9_]*)|(_[a-zA-Z0-9_]+)/

%import python.STRING
%import common.WS
%ignore WS
%ignore COMMENT