val_exp:
| STR { MathQL.Const [$1] }
| FUN STR val_exp { MathQL.Fun ($2, $3) }
| ATTRIB inv ref path val_exp { MathQL.Attribute ($2, $3, $4, $5) }
val_exp:
| STR { MathQL.Const [$1] }
| FUN STR val_exp { MathQL.Fun ($2, $3) }
| ATTRIB inv ref path val_exp { MathQL.Attribute ($2, $3, $4, $5) }