From df6d6a0fa85c07c67eaa40a097953e3290f5d356 Mon Sep 17 00:00:00 2001 From: Marshall Lochbaum Date: Wed, 7 Jul 2021 19:59:57 -0400 Subject: Continued editing and links --- docs/doc/namespace.html | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'docs/doc/namespace.html') diff --git a/docs/doc/namespace.html b/docs/doc/namespace.html index ad38de4e..b8332eae 100644 --- a/docs/doc/namespace.html +++ b/docs/doc/namespace.html @@ -21,7 +21,7 @@

The features of namespaces that make them useful in BQN programming are encapsulation and mutability. But these are exactly the same features that closures provide! In fact a namespace is not much more than a closure with a name lookup system. Consequently namespaces don't really expand the basic functionality of the language, but just make it easier to use.

Namespaces improve encapsulation by allowing many values to be exported at once. With only one way to call them, functions and modifiers aren't such a good way to define a large part of a program. With a namespace you can define lots of things and expose exactly the ones you want to the rest of the world. For example, it's typical for files to define namespaces. A reader can see the exported values just by searching for ⇐, and if you're nice, you might declare them all at the beginning of the file. Careful use of exports can guarantee that potentially dangerous functions are used correctly: if it's only valid to call function B after function A has been called, export AB⇐{A𝕩⋄B𝕩} and don't export B.

Mutability means that the behavior of one namespace can change over the course of the program. Mutability is often a liability, so make sure you really need it before leaning too heavily on this property. While there's no way to tell from the outside that a particular namespace is mutable, you can tell it isn't if the source code doesn't contain ↩, as this is the only way it can modify the variables it contains.

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A namespace that makes use of mutability is essentially an object: a collection of state along with operations that act on it. Object-oriented programming is the other major use of namespaces. Contrary to the name, there's never a need to orient your programming around objects, and it's perfectly fine to use an object here or there when you need to, for instance to build a mutable queue of values.

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A namespace that makes use of mutability is essentially an object: a collection of state along with operations that act on it. Object-oriented programming is the other major use of namespaces. Contrary to the name, there's never a need to orient your programming around objects, and it's perfectly fine to use an object here or there when you need to, for instance to build a mutable queue of values.

Exports

The double arrow ⇐ is used to export variables from a block or file, making the result a namespace instead of the result of the last line. There are two ways to export variables. First, ← in the variable definition can be replaced with ⇐ to export the variable as it's defined. Second, an export statement consisting of an assignment target followed by ⇐, with nothing to the right, exports the variables in the target and does nothing else. These export statements can be placed anywhere in the relevant program or body, including before declaration or on the last line, and a given variable can be exported any number of times. The block in the example below has two statements that export variables, exporting a, b, and c.

example ← {
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