rl_lang/docs/entries/concepts/sets/
mod.rs

1use crate::docs::entry::{ConceptCategory, ConceptEntry, DescriptionEntry, DescriptionKind};
2
3pub static SETS: ConceptEntry = ConceptEntry {
4    name: "sets",
5    summary: "",
6    category: ConceptCategory::Syntax,
7    prerequisites: &["arrays"],
8    descriptions: &[
9        DescriptionEntry {
10            kind: DescriptionKind::Explanation,
11            title: None,
12            description: "declare a mutable set with `dec set[<item type>] <n> = {<item>, ...}` - the type in brackets is the shared type of every item",
13            examples: &[
14                "dec set[int] scores = {95, 82, 71}",
15                "dec set[string] names = {\"alice\", \"bob\"}",
16                "dec set[bool] flags = {true, false}",
17            ],
18            expected_output: &[],
19        },
20        DescriptionEntry {
21            kind: DescriptionKind::Explanation,
22            title: None,
23            description: "declare a constant set the same way with `const set[<item type>] <NAME> = {...}`",
24            examples: &["const set[int] LUCKY_NUMBERS = {3, 7, 21}"],
25            expected_output: &[],
26        },
27        DescriptionEntry {
28            kind: DescriptionKind::Explanation,
29            title: None,
30            description: "read an item by its position with `set[index]`, exactly like an array - the first item is index 0",
31            examples: &["dec set[int] scores = {95, 82, 71}\nprintln(scores[0])  // 95"],
32            expected_output: &[],
33        },
34        DescriptionEntry {
35            kind: DescriptionKind::Explanation,
36            title: None,
37            description: "sets are typed like arrays: every item must share one type, checked against the declared item type",
38            examples: &[
39                "dec set[int] scores = {95, 82}\n// dec set[int] bad = {95, \"not a number\"}  // error: type mismatch",
40            ],
41            expected_output: &[],
42        },
43        DescriptionEntry {
44            kind: DescriptionKind::Pitfall,
45            title: None,
46            description: "unlike a mathematical set, duplicate items are not removed and are not rejected - `{1, 1, 1}` is a valid 3-item set with no uniqueness check performed at declaration or runtime",
47            examples: &["dec set[int] xs = {1, 1, 1}  // length is 3, not 1"],
48            expected_output: &[],
49        },
50        DescriptionEntry {
51            kind: DescriptionKind::Pitfall,
52            title: None,
53            description: "`set[index] = value` is rejected - sets do not support index assignment at all, unlike arrays and maps",
54            examples: &[
55                "dec set[int] scores = {95, 82}\n// scores[0] = 100  // error: sets does not support index assigning",
56            ],
57            expected_output: &[],
58        },
59        DescriptionEntry {
60            kind: DescriptionKind::Pitfall,
61            title: None,
62            description: "a set literal `{...}` is only recognized in a `dec set[T]`/`const set[T]` declaration's initializer - writing `{1, 2, 3}` anywhere else (a plain assignment, a function argument, nested inside an array or map literal) is parsed as a map literal instead and fails with `expected ':' after map key`",
63            examples: &[
64                "dec set[int] xs = {1, 2, 3}  // ok - dedicated declaration syntax\n// xs = {4, 5, 6}  // error: parsed as a map literal, not a set",
65            ],
66            expected_output: &[],
67        },
68        DescriptionEntry {
69            kind: DescriptionKind::Note,
70            title: None,
71            description: "unlike map keys, set items are not restricted to hashable types - any type usable in an array (including nested arrays, records, or other sets) can be used as a set item, since a set is stored the same way as an array under the hood",
72            examples: &[],
73            expected_output: &[],
74        },
75        DescriptionEntry {
76            kind: DescriptionKind::Note,
77            title: None,
78            description: "there's no iteration syntax for sets yet (no `for item in set`), and no stdlib module (`set_add`, `set_contains`, `set_remove`, `set_union`, `set_intersect`) - only declaration-site construction and positional `set[index]` reads are currently supported",
79            examples: &[],
80            expected_output: &[],
81        },
82    ],
83    pitfalls: &[
84        "sets don't enforce uniqueness - think of `set[T]` today as sugar for a fixed, non-index-assignable array, not a mathematical set",
85        "a set literal only parses correctly as the initializer of a `dec set[T]`/`const set[T]` declaration - it is not yet a general-purpose expression",
86    ],
87    related: &["arrays", "maps", "types"],
88    related_stdlib: &[],
89    since: Some("v0.1.5"),
90};
rl_lang/docs/entries/concepts/sets/mod.rs

rl_lang/docs/entries/concepts/sets/
mod.rs
