Why does this work in Ruby:

```
"foo" "bar"
# => "foobar"

```

I'm unsure as to why the strings were concatenated instead of a syntax error being given.

I'm curious as to whether or not this is expected behavior and whether or not it's something the parser is responsible for wrangling (two strings without operators is considered a single string) or the language definition itself is specifying this behavior (implicit concat).