diff options
Diffstat (limited to 'tutorial/list.md')
| -rw-r--r-- | tutorial/list.md | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/tutorial/list.md b/tutorial/list.md index bd8071a6..b34587ca 100644 --- a/tutorial/list.md +++ b/tutorial/list.md @@ -41,7 +41,7 @@ The two characters `,` and `⋄` are completely interchangeable, and newline is <!--GEN Primitives ⟨"#%%Comment", "‿% %Strand"⟩ --> -Finally, *strand notation* is a shortcut for simple lists, like one that just lists a few numbers. It's written with the *ligature* `‿`, which has a higher precedence than either functions or operators (and on the BQN keyboard, the ligature is written with a backslash, then a space). A sequence of values joined with ligatures becomes a list, so that for example the following two expressions are equivalent: +Finally, *strand notation* is a shortcut for simple lists, like one that just lists a few numbers. It's written with the *ligature* `‿`, which has a higher precedence than either functions or operators (and is typed with backslash-space on the BQN keyboard). A sequence of values joined with ligatures becomes a list, so that for example the following two expressions are equivalent: ⟨2,+,-⟩ 2‿+‿- @@ -90,7 +90,7 @@ FS ← {𝕩 Enc˜ "g"Attr⟨"font-size",(Fmt𝕨)∾"px"⟩} ⟩ --> -Lists are just one-dimensional arrays. Types are divided into *data types*, which tend to have a subject role, and *operation types*, which tend to have a role matching their type. Also, any value that's not an array, such as everything we used in the last tutorial, is called an *atom*. +Lists are just one-dimensional arrays. These types are divided into *data types*, which correspond to a subject role, and *operation types*, which each have a matching role. Also, any value that's not an array, such as everything we used in the last tutorial, is called an *atom*. ## Arithmetic on lists @@ -140,6 +140,7 @@ Reverse (`⌽`) puts the list back to front. With a left argument `⌽` means Rotate instead, and shifts values over by the specified amount, wrapping those that go off the end to the other side. A positive value rotates to the left, and a negative one rotates right. 2 ⌽ ⟨0,1,2,3,4⟩ + ¯1 ⌽ "bcdea" ### …and modifiers @@ -147,7 +148,7 @@ With a left argument `⌽` means Rotate instead, and shifts values over by the s <!--GEN Primitives ⟨"¨%2%Each", "´%5%Fold", "∾%,%Join%Join To"⟩ --> -The 1-modifier Each (`¨`) applies its operand to every element of a list argument: it's the same as `map` in a functional programming language. With two list arguments (which have to have the same length), Each pairs the corresponding elements from each, a bit like a `zip` function. If one argument is a list and one's an atom, the atom is reused every time instead. +The 1-modifier Each (`¨`) applies its operand to every element of a list argument, like `map` in a functional programming language. With two list arguments, Each pairs the corresponding elements like arithmetic does, or a bit like a `zip` function (unlike arithmetic, it only goes one level deep). If one argument is a list and one's an atom, the atom is reused every time instead. ⌽¨ "abcd"‿"ABCDEF"‿"01" @@ -167,7 +168,7 @@ To match the order of BQN evaluation, Fold moves over its argument array from ri With this evaluation order, `-´` gives the *alternating sum* of its argument. Think of it this way: the left argument of each `-` is a single number, while the right argument is made up of all the numbers to the right subtracted together. So each `-` flips the sign of every number to its right, and every number is negated by all the `-`s to its left. The first number (`1` above) never gets negated, the second is negated once, the third is negated twice, returning it to its original value… the signs alternate. -*Hey, isn't it dissonant that the first, second, and third numbers are negated zero, one, and two times? If they were the zeroth, first, and second it wouldn't be…* +*Hey, isn't it dissonant that the first, second, and third numbers are negated zero, one, and two times? Not if you call them the zeroth, first, and second…* You can fold with the Join To function to join several lists together: @@ -179,7 +180,7 @@ But you shouldn't! Just `∾` will do the job for you—with no left argument it ## Example: base decoding -Some people like to imagine that robots or other techno-beings speak entirely in binary-encoded ASCII, like for instance "01001110 01100101 01110010 01100100 00100001". This is dumb for a lot of reasons, and the encoded text probably just says something inane, but you're a slave to curiosity and can't ignore it. Are one and a half tutorials of BQN enough to clear your conscience? +Some people like to imagine that robots or other techno-beings speak entirely in binary-encoded ASCII, like for instance "01001110 01100101 01110010 01100100 00100001". This is dumb for a lot of reasons, and the encoded text probably just says something inane, but you're a slave to curiosity and can't ignore it. Are one and two-thirds tutorials of BQN enough to clear your conscience? <!--GEN Primitives ⟨"↕%d%Range%", "⊸%h%Bind?%"⟩ @@ -188,7 +189,7 @@ Almost. It's really close. There are just two things missing, so I'll cover thos ↕ 8 -Natural numbers in BQN start at 0. I'll get to the second function in a moment, but first let's consider how we'd decode just one number in binary. I'll pick a smaller one: 9 is 1001 in binary. Like the first 1 in decimal 1001 counts for one thousand or `10⋆3`, the first one in binary 1001 counts for 8, which is `2⋆3`. We can put each number next to its place value like this: +Natural numbers in BQN start at 0. I'll get to the second primitive in a moment, but first let's consider how we'd decode just one number in binary. I'll pick a smaller one: 9 is 1001 in binary. Like the first 1 in decimal 1001 counts for one thousand or `10⋆3`, the first one in binary 1001 counts for 8, which is `2⋆3`. We can put each number next to its place value like this: 8‿4‿2‿1 ⋈¨ 1‿0‿0‿1 @@ -248,7 +249,7 @@ Was it as anticlimactic as you'd hoped? In fact there's a simpler way to do the ## Summary -There are three types of syntax that create lists: the `"string literal"` for lists of characters and either enclosing angle brackets `⟨⟩` with `,` or `⋄` or newline characters or connecting ligatures `‿` for lists with arbitrary elements. The ligature has a higher precedence than functions or modifiers, so we should add it to our precedence table: +There are three types of syntax that create lists. `"string literal"` gives a list of characters. For arbitrary lists, use enclosing angle brackets `⟨⟩` with `,` or `⋄` or newline between elements, or just connect elements with ligatures `‿`. The ligature has a higher precedence than functions or modifiers and might require parentheses, so we should add it to our precedence table: Precedence | Role | Associativity -----------|----------|-------------- @@ -257,9 +258,9 @@ Precedence | Role | Associativity 2 | Modifier | Left-to-right 3 | Function | Right-to-left -The elements of a list can have any syntactic role; it's ignored and the list as a whole is a subject. +The elements of a list can have any syntactic role. It's ignored and the list as a whole is a subject. -We introduced a few new primitives. The links below go to the full documentation pages for them. +We introduced a few new primitives. The links in the table go to their full documentation pages. Glyph | 1 arg | 2 args ------|------------------------------|-------- @@ -270,6 +271,6 @@ Glyph | 1 arg | 2 args `¨` | [Each](../doc/map.md) | [Each](../doc/map.md#each) `´` | [Fold](../doc/fold.md#fold) -Additionally, we saw that the arithmetic functions work naturally on lists, automatically applying to every element of a single list argument or pairing up the elements of two list arguments. +And we saw that the arithmetic functions work naturally on lists, automatically applying to every element of a single list argument or pairing up the elements of two list arguments. Even this small amount of list functionality is enough to tackle some little problems. We haven't even introduced a function notation yet! |