betelgeuse@pena ~/gsoc/libbash $ ./ast_printer -e "foo=1aa" -memory-(1) : error 3 : ()* loopback of 103:12: ( ( BLANK )+ var_def )*, at offset 4 near [Index: 3 (Start: 144213665-Stop: 144213666) ='aa', type<117> Line: 1 LinePos:4] : cannot match to any predicted input... (LIST Tree Error Node) The value rule should not have num and var_ref as alternatives. fname will cover those cases with a little bit more noise in the ast.
Fixed.