| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `crates/syntax/src/algo.rs`."><title>algo.rs - source</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2"href="../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-ca0dd0c4.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="syntax" data-themes="" data-resource-suffix="" data-rustdoc-version="1.93.0 (254b59607 2026-01-19)" data-channel="1.93.0" data-search-js="search-9e2438ea.js" data-stringdex-js="stringdex-a3946164.js" data-settings-js="settings-c38705f0.js" ><script src="../../static.files/storage-e2aeef58.js"></script><script defer src="../../static.files/src-script-813739b1.js"></script><script defer src="../../src-files.js"></script><script defer src="../../static.files/main-a410ff4d.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-263c88ec.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-eab170b8.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-044be391.svg"></head><body class="rustdoc src"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">syntax/</div>algo.rs</h1><rustdoc-toolbar></rustdoc-toolbar></div><div class="example-wrap digits-3"><pre class="rust"><code><a href=#1 id=1 data-nosnippet>1</a><span class="doccomment">//! Collection of assorted algorithms for syntax trees. |
| <a href=#2 id=2 data-nosnippet>2</a> |
| <a href=#3 id=3 data-nosnippet>3</a></span><span class="kw">use </span>itertools::Itertools; |
| <a href=#4 id=4 data-nosnippet>4</a> |
| <a href=#5 id=5 data-nosnippet>5</a><span class="kw">use crate</span>::{ |
| <a href=#6 id=6 data-nosnippet>6</a> AstNode, Direction, NodeOrToken, SyntaxElement, SyntaxKind, SyntaxNode, SyntaxToken, TextRange, |
| <a href=#7 id=7 data-nosnippet>7</a> TextSize, syntax_editor::Element, |
| <a href=#8 id=8 data-nosnippet>8</a>}; |
| <a href=#9 id=9 data-nosnippet>9</a> |
| <a href=#10 id=10 data-nosnippet>10</a><span class="doccomment">/// Returns ancestors of the node at the offset, sorted by length. This should |
| <a href=#11 id=11 data-nosnippet>11</a>/// do the right thing at an edge, e.g. when searching for expressions at `{ |
| <a href=#12 id=12 data-nosnippet>12</a>/// $0foo }` we will get the name reference instead of the whole block, which |
| <a href=#13 id=13 data-nosnippet>13</a>/// we would get if we just did `find_token_at_offset(...).flat_map(|t| |
| <a href=#14 id=14 data-nosnippet>14</a>/// t.parent().ancestors())`. |
| <a href=#15 id=15 data-nosnippet>15</a></span><span class="kw">pub fn </span>ancestors_at_offset( |
| <a href=#16 id=16 data-nosnippet>16</a> node: <span class="kw-2">&</span>SyntaxNode, |
| <a href=#17 id=17 data-nosnippet>17</a> offset: TextSize, |
| <a href=#18 id=18 data-nosnippet>18</a>) -> <span class="kw">impl </span>Iterator<Item = SyntaxNode> { |
| <a href=#19 id=19 data-nosnippet>19</a> node.token_at_offset(offset) |
| <a href=#20 id=20 data-nosnippet>20</a> .map(|token| token.parent_ancestors()) |
| <a href=#21 id=21 data-nosnippet>21</a> .kmerge_by(|node1, node2| node1.text_range().len() < node2.text_range().len()) |
| <a href=#22 id=22 data-nosnippet>22</a>} |
| <a href=#23 id=23 data-nosnippet>23</a> |
| <a href=#24 id=24 data-nosnippet>24</a><span class="doccomment">/// Finds a node of specific Ast type at offset. Note that this is slightly |
| <a href=#25 id=25 data-nosnippet>25</a>/// imprecise: if the cursor is strictly between two nodes of the desired type, |
| <a href=#26 id=26 data-nosnippet>26</a>/// as in |
| <a href=#27 id=27 data-nosnippet>27</a>/// |
| <a href=#28 id=28 data-nosnippet>28</a>/// ```ignore |
| <a href=#29 id=29 data-nosnippet>29</a>/// struct Foo {}|struct Bar; |
| <a href=#30 id=30 data-nosnippet>30</a>/// ``` |
| <a href=#31 id=31 data-nosnippet>31</a>/// |
| <a href=#32 id=32 data-nosnippet>32</a>/// then the shorter node will be silently preferred. |
| <a href=#33 id=33 data-nosnippet>33</a></span><span class="kw">pub fn </span>find_node_at_offset<N: AstNode>(syntax: <span class="kw-2">&</span>SyntaxNode, offset: TextSize) -> <span class="prelude-ty">Option</span><N> { |
| <a href=#34 id=34 data-nosnippet>34</a> ancestors_at_offset(syntax, offset).find_map(N::cast) |
| <a href=#35 id=35 data-nosnippet>35</a>} |
| <a href=#36 id=36 data-nosnippet>36</a> |
| <a href=#37 id=37 data-nosnippet>37</a><span class="kw">pub fn </span>find_node_at_range<N: AstNode>(syntax: <span class="kw-2">&</span>SyntaxNode, range: TextRange) -> <span class="prelude-ty">Option</span><N> { |
| <a href=#38 id=38 data-nosnippet>38</a> syntax.covering_element(range).ancestors().find_map(N::cast) |
| <a href=#39 id=39 data-nosnippet>39</a>} |
| <a href=#40 id=40 data-nosnippet>40</a> |
| <a href=#41 id=41 data-nosnippet>41</a><span class="doccomment">/// Skip to next non `trivia` token |
| <a href=#42 id=42 data-nosnippet>42</a></span><span class="kw">pub fn </span>skip_trivia_token(<span class="kw-2">mut </span>token: SyntaxToken, direction: Direction) -> <span class="prelude-ty">Option</span><SyntaxToken> { |
| <a href=#43 id=43 data-nosnippet>43</a> <span class="kw">while </span>token.kind().is_trivia() { |
| <a href=#44 id=44 data-nosnippet>44</a> token = <span class="kw">match </span>direction { |
| <a href=#45 id=45 data-nosnippet>45</a> Direction::Next => token.next_token()<span class="question-mark">?</span>, |
| <a href=#46 id=46 data-nosnippet>46</a> Direction::Prev => token.prev_token()<span class="question-mark">?</span>, |
| <a href=#47 id=47 data-nosnippet>47</a> } |
| <a href=#48 id=48 data-nosnippet>48</a> } |
| <a href=#49 id=49 data-nosnippet>49</a> <span class="prelude-val">Some</span>(token) |
| <a href=#50 id=50 data-nosnippet>50</a>} |
| <a href=#51 id=51 data-nosnippet>51</a><span class="doccomment">/// Skip to next non `whitespace` token |
| <a href=#52 id=52 data-nosnippet>52</a></span><span class="kw">pub fn </span>skip_whitespace_token(<span class="kw-2">mut </span>token: SyntaxToken, direction: Direction) -> <span class="prelude-ty">Option</span><SyntaxToken> { |
| <a href=#53 id=53 data-nosnippet>53</a> <span class="kw">while </span>token.kind() == SyntaxKind::WHITESPACE { |
| <a href=#54 id=54 data-nosnippet>54</a> token = <span class="kw">match </span>direction { |
| <a href=#55 id=55 data-nosnippet>55</a> Direction::Next => token.next_token()<span class="question-mark">?</span>, |
| <a href=#56 id=56 data-nosnippet>56</a> Direction::Prev => token.prev_token()<span class="question-mark">?</span>, |
| <a href=#57 id=57 data-nosnippet>57</a> } |
| <a href=#58 id=58 data-nosnippet>58</a> } |
| <a href=#59 id=59 data-nosnippet>59</a> <span class="prelude-val">Some</span>(token) |
| <a href=#60 id=60 data-nosnippet>60</a>} |
| <a href=#61 id=61 data-nosnippet>61</a> |
| <a href=#62 id=62 data-nosnippet>62</a><span class="doccomment">/// Finds the first sibling in the given direction which is not `trivia` |
| <a href=#63 id=63 data-nosnippet>63</a></span><span class="kw">pub fn </span>non_trivia_sibling(element: SyntaxElement, direction: Direction) -> <span class="prelude-ty">Option</span><SyntaxElement> { |
| <a href=#64 id=64 data-nosnippet>64</a> <span class="kw">return match </span>element { |
| <a href=#65 id=65 data-nosnippet>65</a> NodeOrToken::Node(node) => node.siblings_with_tokens(direction).skip(<span class="number">1</span>).find(not_trivia), |
| <a href=#66 id=66 data-nosnippet>66</a> NodeOrToken::Token(token) => token.siblings_with_tokens(direction).skip(<span class="number">1</span>).find(not_trivia), |
| <a href=#67 id=67 data-nosnippet>67</a> }; |
| <a href=#68 id=68 data-nosnippet>68</a> |
| <a href=#69 id=69 data-nosnippet>69</a> <span class="kw">fn </span>not_trivia(element: <span class="kw-2">&</span>SyntaxElement) -> bool { |
| <a href=#70 id=70 data-nosnippet>70</a> <span class="kw">match </span>element { |
| <a href=#71 id=71 data-nosnippet>71</a> NodeOrToken::Node(<span class="kw">_</span>) => <span class="bool-val">true</span>, |
| <a href=#72 id=72 data-nosnippet>72</a> NodeOrToken::Token(token) => !token.kind().is_trivia(), |
| <a href=#73 id=73 data-nosnippet>73</a> } |
| <a href=#74 id=74 data-nosnippet>74</a> } |
| <a href=#75 id=75 data-nosnippet>75</a>} |
| <a href=#76 id=76 data-nosnippet>76</a> |
| <a href=#77 id=77 data-nosnippet>77</a><span class="kw">pub fn </span>least_common_ancestor(u: <span class="kw-2">&</span>SyntaxNode, v: <span class="kw-2">&</span>SyntaxNode) -> <span class="prelude-ty">Option</span><SyntaxNode> { |
| <a href=#78 id=78 data-nosnippet>78</a> <span class="kw">if </span>u == v { |
| <a href=#79 id=79 data-nosnippet>79</a> <span class="kw">return </span><span class="prelude-val">Some</span>(u.clone()); |
| <a href=#80 id=80 data-nosnippet>80</a> } |
| <a href=#81 id=81 data-nosnippet>81</a> |
| <a href=#82 id=82 data-nosnippet>82</a> <span class="kw">let </span>u_depth = u.ancestors().count(); |
| <a href=#83 id=83 data-nosnippet>83</a> <span class="kw">let </span>v_depth = v.ancestors().count(); |
| <a href=#84 id=84 data-nosnippet>84</a> <span class="kw">let </span>keep = u_depth.min(v_depth); |
| <a href=#85 id=85 data-nosnippet>85</a> |
| <a href=#86 id=86 data-nosnippet>86</a> <span class="kw">let </span>u_candidates = u.ancestors().skip(u_depth - keep); |
| <a href=#87 id=87 data-nosnippet>87</a> <span class="kw">let </span>v_candidates = v.ancestors().skip(v_depth - keep); |
| <a href=#88 id=88 data-nosnippet>88</a> <span class="kw">let </span>(res, <span class="kw">_</span>) = u_candidates.zip(v_candidates).find(|(x, y)| x == y)<span class="question-mark">?</span>; |
| <a href=#89 id=89 data-nosnippet>89</a> <span class="prelude-val">Some</span>(res) |
| <a href=#90 id=90 data-nosnippet>90</a>} |
| <a href=#91 id=91 data-nosnippet>91</a> |
| <a href=#92 id=92 data-nosnippet>92</a><span class="kw">pub fn </span>least_common_ancestor_element(u: <span class="kw">impl </span>Element, v: <span class="kw">impl </span>Element) -> <span class="prelude-ty">Option</span><SyntaxNode> { |
| <a href=#93 id=93 data-nosnippet>93</a> <span class="kw">let </span>u = u.syntax_element(); |
| <a href=#94 id=94 data-nosnippet>94</a> <span class="kw">let </span>v = v.syntax_element(); |
| <a href=#95 id=95 data-nosnippet>95</a> <span class="kw">if </span>u == v { |
| <a href=#96 id=96 data-nosnippet>96</a> <span class="kw">return match </span>u { |
| <a href=#97 id=97 data-nosnippet>97</a> NodeOrToken::Node(node) => <span class="prelude-val">Some</span>(node), |
| <a href=#98 id=98 data-nosnippet>98</a> NodeOrToken::Token(token) => token.parent(), |
| <a href=#99 id=99 data-nosnippet>99</a> }; |
| <a href=#100 id=100 data-nosnippet>100</a> } |
| <a href=#101 id=101 data-nosnippet>101</a> |
| <a href=#102 id=102 data-nosnippet>102</a> <span class="kw">let </span>u_depth = u.ancestors().count(); |
| <a href=#103 id=103 data-nosnippet>103</a> <span class="kw">let </span>v_depth = v.ancestors().count(); |
| <a href=#104 id=104 data-nosnippet>104</a> <span class="kw">let </span>keep = u_depth.min(v_depth); |
| <a href=#105 id=105 data-nosnippet>105</a> |
| <a href=#106 id=106 data-nosnippet>106</a> <span class="kw">let </span>u_candidates = u.ancestors().skip(u_depth - keep); |
| <a href=#107 id=107 data-nosnippet>107</a> <span class="kw">let </span>v_candidates = v.ancestors().skip(v_depth - keep); |
| <a href=#108 id=108 data-nosnippet>108</a> <span class="kw">let </span>(res, <span class="kw">_</span>) = u_candidates.zip(v_candidates).find(|(x, y)| x == y)<span class="question-mark">?</span>; |
| <a href=#109 id=109 data-nosnippet>109</a> <span class="prelude-val">Some</span>(res) |
| <a href=#110 id=110 data-nosnippet>110</a>} |
| <a href=#111 id=111 data-nosnippet>111</a> |
| <a href=#112 id=112 data-nosnippet>112</a><span class="kw">pub fn </span>neighbor<T: AstNode>(me: <span class="kw-2">&</span>T, direction: Direction) -> <span class="prelude-ty">Option</span><T> { |
| <a href=#113 id=113 data-nosnippet>113</a> me.syntax().siblings(direction).skip(<span class="number">1</span>).find_map(T::cast) |
| <a href=#114 id=114 data-nosnippet>114</a>} |
| <a href=#115 id=115 data-nosnippet>115</a> |
| <a href=#116 id=116 data-nosnippet>116</a><span class="kw">pub fn </span>has_errors(node: <span class="kw-2">&</span>SyntaxNode) -> bool { |
| <a href=#117 id=117 data-nosnippet>117</a> node.children().any(|it| it.kind() == SyntaxKind::ERROR) |
| <a href=#118 id=118 data-nosnippet>118</a>} |
| <a href=#119 id=119 data-nosnippet>119</a> |
| <a href=#120 id=120 data-nosnippet>120</a><span class="kw">pub fn </span>previous_non_trivia_token(e: <span class="kw">impl </span>Into<SyntaxElement>) -> <span class="prelude-ty">Option</span><SyntaxToken> { |
| <a href=#121 id=121 data-nosnippet>121</a> <span class="kw">let </span><span class="kw-2">mut </span>token = <span class="kw">match </span>e.into() { |
| <a href=#122 id=122 data-nosnippet>122</a> SyntaxElement::Node(n) => n.first_token()<span class="question-mark">?</span>, |
| <a href=#123 id=123 data-nosnippet>123</a> SyntaxElement::Token(t) => t, |
| <a href=#124 id=124 data-nosnippet>124</a> } |
| <a href=#125 id=125 data-nosnippet>125</a> .prev_token(); |
| <a href=#126 id=126 data-nosnippet>126</a> <span class="kw">while let </span><span class="prelude-val">Some</span>(inner) = token { |
| <a href=#127 id=127 data-nosnippet>127</a> <span class="kw">if </span>!inner.kind().is_trivia() { |
| <a href=#128 id=128 data-nosnippet>128</a> <span class="kw">return </span><span class="prelude-val">Some</span>(inner); |
| <a href=#129 id=129 data-nosnippet>129</a> } <span class="kw">else </span>{ |
| <a href=#130 id=130 data-nosnippet>130</a> token = inner.prev_token(); |
| <a href=#131 id=131 data-nosnippet>131</a> } |
| <a href=#132 id=132 data-nosnippet>132</a> } |
| <a href=#133 id=133 data-nosnippet>133</a> <span class="prelude-val">None |
| <a href=#134 id=134 data-nosnippet>134</a></span>} |
| </code></pre></div></section></main></body></html> |
