obeli_sk_boa_ast/
lib.rs

1//! Boa's **`boa_ast`** crate implements an ECMAScript abstract syntax tree.
2//!
3//! # Crate Overview
4//! **`boa_ast`** contains representations of [**Parse Nodes**][grammar] as defined by the ECMAScript
5//! spec. Some `Parse Node`s are not represented by Boa's AST, because a lot of grammar productions
6//! are only used to throw [**Early Errors**][early], and don't influence the evaluation of the AST
7//! itself.
8//!
9//! Boa's AST is mainly split in three main components: [`Declaration`]s, [`Expression`]s and
10//! [`Statement`]s, with [`StatementList`] being the primordial Parse Node that combines
11//! all of them to create a proper AST.
12//!
13//! [grammar]: https://tc39.es/ecma262/#sec-syntactic-grammar
14//! [early]: https://tc39.es/ecma262/#sec-static-semantic-rules
15#![doc = include_str!("../ABOUT.md")]
16#![doc(
17    html_logo_url = "https://raw.githubusercontent.com/boa-dev/boa/main/assets/logo_black.svg",
18    html_favicon_url = "https://raw.githubusercontent.com/boa-dev/boa/main/assets/logo_black.svg"
19)]
20#![cfg_attr(not(test), forbid(clippy::unwrap_used))]
21#![allow(
22    clippy::module_name_repetitions,
23    clippy::too_many_lines,
24    clippy::option_if_let_else
25)]
26
27mod module_item_list;
28mod position;
29mod punctuator;
30mod source;
31mod source_text;
32mod statement_list;
33
34pub mod declaration;
35pub mod expression;
36pub mod function;
37pub mod keyword;
38pub mod operations;
39pub mod pattern;
40pub mod property;
41pub mod scope;
42pub mod scope_analyzer;
43pub mod statement;
44pub mod visitor;
45
46use boa_interner::{Interner, Sym, ToIndentedString, ToInternedString};
47use boa_string::{JsStr, JsString};
48use expression::Identifier;
49
50pub use self::{
51    declaration::Declaration,
52    expression::Expression,
53    keyword::Keyword,
54    module_item_list::{ModuleItem, ModuleItemList},
55    position::{
56        LinearPosition, LinearSpan, LinearSpanIgnoreEq, Position, PositionGroup, Span, Spanned,
57    },
58    punctuator::Punctuator,
59    source::{Module, Script},
60    source_text::SourceText,
61    statement::Statement,
62    statement_list::{StatementList, StatementListItem},
63};
64
65/// Utility to join multiple Nodes into a single string.
66fn join_nodes<N>(interner: &Interner, nodes: &[N]) -> String
67where
68    N: ToInternedString,
69{
70    let mut first = true;
71    let mut buf = String::new();
72    for e in nodes {
73        if first {
74            first = false;
75        } else {
76            buf.push_str(", ");
77        }
78        buf.push_str(&e.to_interned_string(interner));
79    }
80    buf
81}
82
83/// Displays the body of a block or statement list.
84///
85/// This includes the curly braces at the start and end. This will not indent the first brace,
86/// but will indent the last brace.
87fn block_to_string(body: &StatementList, interner: &Interner, indentation: usize) -> String {
88    if body.statements().is_empty() {
89        "{}".to_owned()
90    } else {
91        format!(
92            "{{\n{}{}}}",
93            body.to_indented_string(interner, indentation + 1),
94            "    ".repeat(indentation)
95        )
96    }
97}
98
99/// Utility trait that adds a `UTF-16` escaped representation to every [`[u16]`][slice].
100trait ToStringEscaped {
101    /// Decodes `self` as an `UTF-16` encoded string, escaping any unpaired surrogates by its
102    /// codepoint value.
103    fn to_string_escaped(&self) -> String;
104}
105
106impl ToStringEscaped for [u16] {
107    fn to_string_escaped(&self) -> String {
108        char::decode_utf16(self.iter().copied())
109            .map(|r| match r {
110                Ok(c) => String::from(c),
111                Err(e) => format!("\\u{:04X}", e.unpaired_surrogate()),
112            })
113            .collect()
114    }
115}
116
117pub(crate) trait ToJsString {
118    fn to_js_string(&self, interner: &Interner) -> JsString;
119}
120
121impl ToJsString for Sym {
122    #[allow(clippy::cast_possible_truncation)]
123    fn to_js_string(&self, interner: &Interner) -> JsString {
124        let utf16 = interner.resolve_expect(*self).utf16();
125        if interner.is_latin1(*self) {
126            let bytes: Vec<u8> = utf16.iter().map(|&c| c as u8).collect();
127            JsString::from(JsStr::latin1(&bytes))
128        } else {
129            JsString::from(utf16)
130        }
131    }
132}
133
134impl ToJsString for Identifier {
135    fn to_js_string(&self, interner: &Interner) -> JsString {
136        self.sym().to_js_string(interner)
137    }
138}
obeli_sk_boa_ast/lib.rs

obeli_sk_boa_ast/
lib.rs
