DCG Syntax

I really want DCGs to be easy to write *and easy to read*. This example fails the 2nd condition:

```yaml
[story]
- "Once upon a time there was a"
- [Subject]
- "who was very hungry."
```

Wouldn't it be better to write:

```yaml
[story] {
"Once upon a time there was a" [Subject] "who was very hungry."
}
```

I guess this is solved by text template literals:

```yaml
[story]
"Once upon a time there was a [[Subject]] who was very hungry."
```