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

1use crate::docs::entry::{ConceptCategory, ConceptEntry, DescriptionEntry, DescriptionKind};
2
3pub static MAPS: ConceptEntry = ConceptEntry {
4    name: "maps",
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 map with `dec map[<key type>, <value type>] <n> = {<key>: <value>, ...}`",
13            examples: &[
14                "dec map[string, int] scores = {\"alice\": 95, \"bob\": 82}",
15                "dec map[int, string] names = {1: \"one\", 2: \"two\"}",
16                "dec map[string, bool] flags = {\"dark_mode\": true}",
17            ],
18            expected_output: &[],
19        },
20        DescriptionEntry {
21            kind: DescriptionKind::Explanation,
22            title: None,
23            description: "read a value by key with `map[key]`",
24            examples: &[
25                "dec map[string, int] scores = {\"alice\": 95, \"bob\": 82}\nprintln(scores[\"alice\"])  // 95",
26            ],
27            expected_output: &[],
28        },
29        DescriptionEntry {
30            kind: DescriptionKind::Explanation,
31            title: None,
32            description: "write or update a value by key with `map[key] = value` - this both inserts new keys and overwrites existing ones",
33            examples: &[
34                "dec map[string, int] scores = {\"alice\": 95}\nscores[\"bob\"] = 82  // insert\nscores[\"alice\"] = 100 // overwrite",
35            ],
36            expected_output: &[],
37        },
38        DescriptionEntry {
39            kind: DescriptionKind::Explanation,
40            title: None,
41            description: "maps are typed like arrays: every key must share one type, and every value must share one type",
42            examples: &[
43                "dec map[string, int] scores = {\"alice\": 95}\n// scores[\"bob\"] = \"not a number\"  // error: type mismatch",
44            ],
45            expected_output: &[],
46        },
47        DescriptionEntry {
48            kind: DescriptionKind::Explanation,
49            title: None,
50            description: "only int, string, bool, byte, and char can be used as key types - float keys are rejected, since floating point equality is unreliable for lookup",
51            examples: &[
52                "// dec map[float, int] bad = {1.5: 1}  // error: float cannot be used as a map key",
53            ],
54            expected_output: &[],
55        },
56        DescriptionEntry {
57            kind: DescriptionKind::Explanation,
58            title: None,
59            description: "map values can be any type, including arrays or other maps",
60            examples: &[
61                "dec map[string, array[int]] rosters = {\"team_a\": [1, 2, 3]}\ndec map[string, map[string, int]] nested = {\"round1\": {\"alice\": 10}}",
62            ],
63            expected_output: &[],
64        },
65        DescriptionEntry {
66            kind: DescriptionKind::Pitfall,
67            title: None,
68            description: "reading a key that doesn't exist is a runtime error, not `null` - there is no `map_get`-with-default yet, so check with a lookup helper once the map stdlib module exists, or guard with a `match`/`if`",
69            examples: &[],
70            expected_output: &[],
71        },
72        DescriptionEntry {
73            kind: DescriptionKind::Note,
74            title: None,
75            description: "there's no iteration syntax for maps yet (no `for key, value in map`), and no stdlib module (`map_get`, `map_keys`, `map_values`, `map_has`, `map_remove`) - only literal construction and single-level `map[key]` read/write are currently supported",
76            examples: &[],
77            expected_output: &[],
78        },
79    ],
80    pitfalls: &[
81        "assigning through more than one level of nesting, e.g. `arr[0][\"key\"] = value` where the outer container is an array of maps, is not yet supported - only a bare `map[key] = value` works",
82    ],
83    related: &["arrays", "types"],
84    related_stdlib: &[],
85    since: Some("v0.1.5"),
86};
rl_lang/docs/entries/concepts/maps/mod.rs

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