Text containers

Text containers avoid annoying repetition when a lot of strings are needed. They put to light the usefulness of line-strings. A text container is preceded by ::. Only the list and tuple can be text containers. Using :: followed by braces creates a multiline-string, and while a text template head is allowed, this is not the way to get one.

Text list

A text list can only contain string values. However, a list can be expanded inside it, as explained below. It’s import to understand that a text container is only a convenience for the programmer; it doesn’t enforce string values.

["s1", "s2", "s3"], [:s1, :s2, :s3], and ::[s1, s2, s3] are all equivalent.

Text tuple

As written above, a text container is merely a convenience to easily write a lot of strings. In a tuple, a key can still be assigned a value. This is done by using the explicit name char.

(:text, key=N, :more text) and ::(text, $key=N, more text) are equivalent.

Expand

A container can be expanded within a text container. The expanded container doesn’t need to be a text container itself. The values in the container are not converted to strings.

The following code is valid:

?numberedList[0, 1, 2, 3]

confusingList::[^numberedList, 4, 5, 6]

The value of confusingList is equivalent to [0, 1, 2, 3, "4", "5", "6"].

Separator

The empty line-string behaves differently in a text container. While [:, :] and ["", ""] are equivalent, ::[,] would create an error. To use an empty string within a text container, an escape must be used: ::[\e, \e] is equivalent to the two working examples.

This behavior allows the default value of a template head to be used while having a text tuple. For instance, <k1:s1, k2:s2, k3:s3>::(, s2, s3) is equivalent to <k1:s1, k2:s2, k3:s3>(, :s2, :s3).

As a helpful summary, the chars to be wary of in a text container are: $, ^, and ,. They might behave unexpectedly if you think every value in a text container behaves as if an implicit : was put before them (that’s a good way to see how everything else behaves).

End of line-string

In some other pages, it is written that the behavior of line-strings depends on context without giving further details. Here’s perhaps a good place to explain exactly how they behave.

Line-strings behave differently depending on which container they are in. But they only might be terminated by its end char or the separator. They are however always terminated by the newline.

Whether or not the end char of the container or the separator terminates line-strings is determined by how the container in which they are started. If there is any non-junk character on the same line as the start char of the container, then the separator will always terminate them. Such a container is called a “line” container. The opposite is called a “multiline” container. (I will eventually figure out a better terminology since this brings confusion with the multiline-string, which can be both “line” and “multiline”.) This explains why something like [:text, :text,] is equivalent to ["text", "text"].

The end char of the container, however, might end it.

In a “line” container, the start and end chars of the container are kept track of within line-strings. This means that if the start and end of a container are paired, then the end char doesn’t end the line-string. For instance, (:()(), :([()])) is equivalent to ("()()", "([()])").

In a “multiline” container, the separator and the end char never end line-strings.

[
	:A short poem, using commas, :And symbols like ] and }
]

This equivalent to ["A short poem, using commas, :And symbols like ] and }"]!

The document is a “multiline” container.