Lines

A line is what a character says. It is written as the name of the speaker, a :, and the text:

:= start
Alice: Hi! How are you?
Bob: Great, and you?
---

The speaker is whatever comes before the first : of the line, so a name can hold spaces: Old man: Who goes there?.

Lines without a speaker

A line with no : has no speaker. It suits a narrator, or a description:

:= start
The door creaks open.
Alice: Who is there?
---

Since whatever comes before the first : is read as the speaker, a line without a speaker cannot hold a : in its text.

An expression between [ and ] is evaluated when the line is reached, and replaced by its value:

:= start
[let $name = "Alice"]
[let $gold = 3]
Bob: Hello [$name], you owe me [$gold * 100] cents.
---

Anything described in Expressions can stand between the brackets. A line can also carry tags.