From 0d6c26b9aa607ff14e14e6488bace207e324022a Mon Sep 17 00:00:00 2001 From: Marshall Lochbaum Date: Mon, 13 Jun 2022 13:20:34 -0400 Subject: =?UTF-8?q?Highlight=20[]=20as=20list=20brackets,=20like=20?= =?UTF-8?q?=E2=9F=A8=E2=9F=A9?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- docs/doc/embed.html | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'docs/doc/embed.html') diff --git a/docs/doc/embed.html b/docs/doc/embed.html index b02342cc..b911046d 100644 --- a/docs/doc/embed.html +++ b/docs/doc/embed.html @@ -16,13 +16,13 @@ i←4β₯Š0 {i+↩𝕩»i} `); -push(3); // [3,0,0,0] -push(-2); // [1,3,0,0] -push(4); // [5,4,3,0] +push(3); // [3,0,0,0] +push(-2); // [1,3,0,0] +push(4); // [5,4,3,0]

Note that this program doesn't have any outer braces. It's only run once, and it initializes i and returns a function. Just putting braces around it wouldn't have any effectβ€”it just changes it from a program that does something to a program that runs a block that does the same thingβ€”but adding braces and using 𝕨 or 𝕩 inside them would turn it into a function that could be run multiple times to create different closures. For example, pushGen = bqn("{i←4β₯Šπ•©β‹„{i+↩𝕩»i}}") causes pushGen(n) to create a new closure with i initialized to 4β₯Šn.

The program also returns only one function, which can be limiting. But it's possible to get multiple closures out of the same program by returning a list of functions. For example, the following program defines three functions that manipulate a shared array in different ways.

-
let [rotx, roty, flip] = bqn(`
+
let [rotx, roty, flip] = bqn(`
     a ← 3β€Ώ2β₯Šβ†•6
     RotX ← {aβ†©π•©βŒ½Λ˜a}
     RotY ← {aβ†©π•©βŒ½a}
@@ -35,7 +35,7 @@
 
JS encodings

 
In the programs above we've used numbers and functions of one argument, which mean the same thing in BQN and JS. This isn't the case for all types: although every BQN value is stored as some JS value, the way it's represented may not be obvious and there are many JS values that don't represent any BQN value and could cause errors. BQN operations don't verify that their inputs are valid BQN values (this would have a large performance cost), so it's up to the JS programmer to make sure that values passed in are valid. To do this, you need to know the encodings for each of the seven BQN types you're going to use.

 
The two atomic data values are simple: numbers are just JS numbers, and characters are strings containing a single code point. Arrays are JS arrays, but with some extra information. Since JS arrays are 1-dimensional, a BQN array a is stored as the element list β₯Ša. Its shape β‰’a, a list of numbers, is a.sh in JS (the shape isn't necessarily a BQN array so it doesn't have to have a sh property). Optionally, its fill element is a.fill. Note that a BQN string is not a JS string, but instead an array of BQN characters, or JS strings. To convert it to a JS string you can use str.join("").

-
There are two utilities for converting from JS to BQN data: list([…]) converts a JS array to a BQN list, and str("JS string") converts a string.

+
There are two utilities for converting from JS to BQN data: list([…]) converts a JS array to a BQN list, and str("JS string") converts a string.

 
Operations are all stored as JS functions, with one or two arguments for the inputs. The type is determined by the .m property, which is 1 for a 1-modifier and 2 for a 2-modifier, and undefined or falsy for a function. Functions might be called with one or two arguments. In either case, 𝕩 is the first argument; 𝕨, if present, is the second. Note that F(x,w) in JS corresponds to w F x in BQN, reversing the visual ordering of the arguments! For modifiers there's no such reversal, as 𝕗 is always the first argument, and for 2-modifiers π•˜ is the second argument. As in BQN, a modifier may or may not return a function.

 
Operations may have some extra properties set that aren't terribly important for the JS programmer: for each primitive p, p.glyph gives its glyph, and for a compound operation o such as a train, or a modifier with bound operands, o.repr() decomposes it into its parts. It wouldn't make sense to define either of these properties for a function created in JS.

 
Other functionality

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