| <!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/tt/src/buffer.rs`."><title>buffer.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" crossorigin href="../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-84e720fa.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="tt" data-themes="" data-resource-suffix="" data-rustdoc-version="1.89.0 (29483883e 2025-08-04)" data-channel="1.89.0" data-search-js="search-92309212.js" data-settings-js="settings-5514c975.js" ><script src="../../static.files/storage-4e99c027.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-fd3af306.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-32bb7600.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-6580c154.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><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">tt/</div>buffer.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">//! Stateful iteration over token trees. |
| <a href=#2 id=2 data-nosnippet>2</a>//! |
| <a href=#3 id=3 data-nosnippet>3</a>//! We use this as the source of tokens for parser. |
| <a href=#4 id=4 data-nosnippet>4</a></span><span class="kw">use crate</span>::{Leaf, Subtree, TokenTree, TokenTreesView}; |
| <a href=#5 id=5 data-nosnippet>5</a> |
| <a href=#6 id=6 data-nosnippet>6</a><span class="kw">pub struct </span>Cursor<<span class="lifetime">'a</span>, Span> { |
| <a href=#7 id=7 data-nosnippet>7</a> buffer: <span class="kw-2">&</span><span class="lifetime">'a </span>[TokenTree<Span>], |
| <a href=#8 id=8 data-nosnippet>8</a> index: usize, |
| <a href=#9 id=9 data-nosnippet>9</a> subtrees_stack: Vec<usize>, |
| <a href=#10 id=10 data-nosnippet>10</a>} |
| <a href=#11 id=11 data-nosnippet>11</a> |
| <a href=#12 id=12 data-nosnippet>12</a><span class="kw">impl</span><<span class="lifetime">'a</span>, Span: Copy> Cursor<<span class="lifetime">'a</span>, Span> { |
| <a href=#13 id=13 data-nosnippet>13</a> <span class="kw">pub fn </span>new(buffer: <span class="kw-2">&</span><span class="lifetime">'a </span>[TokenTree<Span>]) -> <span class="self">Self </span>{ |
| <a href=#14 id=14 data-nosnippet>14</a> <span class="self">Self </span>{ buffer, index: <span class="number">0</span>, subtrees_stack: Vec::new() } |
| <a href=#15 id=15 data-nosnippet>15</a> } |
| <a href=#16 id=16 data-nosnippet>16</a> |
| <a href=#17 id=17 data-nosnippet>17</a> <span class="doccomment">/// Check whether it is eof |
| <a href=#18 id=18 data-nosnippet>18</a> </span><span class="kw">pub fn </span>eof(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#19 id=19 data-nosnippet>19</a> <span class="self">self</span>.index == <span class="self">self</span>.buffer.len() && <span class="self">self</span>.subtrees_stack.is_empty() |
| <a href=#20 id=20 data-nosnippet>20</a> } |
| <a href=#21 id=21 data-nosnippet>21</a> |
| <a href=#22 id=22 data-nosnippet>22</a> <span class="kw">pub fn </span>is_root(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#23 id=23 data-nosnippet>23</a> <span class="self">self</span>.subtrees_stack.is_empty() |
| <a href=#24 id=24 data-nosnippet>24</a> } |
| <a href=#25 id=25 data-nosnippet>25</a> |
| <a href=#26 id=26 data-nosnippet>26</a> <span class="kw">fn </span>last_subtree(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><(usize, <span class="kw-2">&</span><span class="lifetime">'a </span>Subtree<Span>)> { |
| <a href=#27 id=27 data-nosnippet>27</a> <span class="self">self</span>.subtrees_stack.last().map(|<span class="kw-2">&</span>subtree_idx| { |
| <a href=#28 id=28 data-nosnippet>28</a> <span class="kw">let </span>TokenTree::Subtree(subtree) = <span class="kw-2">&</span><span class="self">self</span>.buffer[subtree_idx] <span class="kw">else </span>{ |
| <a href=#29 id=29 data-nosnippet>29</a> <span class="macro">panic!</span>(<span class="string">"subtree pointing to non-subtree"</span>); |
| <a href=#30 id=30 data-nosnippet>30</a> }; |
| <a href=#31 id=31 data-nosnippet>31</a> (subtree_idx, subtree) |
| <a href=#32 id=32 data-nosnippet>32</a> }) |
| <a href=#33 id=33 data-nosnippet>33</a> } |
| <a href=#34 id=34 data-nosnippet>34</a> |
| <a href=#35 id=35 data-nosnippet>35</a> <span class="kw">pub fn </span>end(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="lifetime">'a </span>Subtree<Span> { |
| <a href=#36 id=36 data-nosnippet>36</a> <span class="kw">let </span>(last_subtree_idx, last_subtree) = |
| <a href=#37 id=37 data-nosnippet>37</a> <span class="self">self</span>.last_subtree().expect(<span class="string">"called `Cursor::end()` without an open subtree"</span>); |
| <a href=#38 id=38 data-nosnippet>38</a> <span class="comment">// +1 because `Subtree.len` excludes the subtree itself. |
| <a href=#39 id=39 data-nosnippet>39</a> </span><span class="macro">assert_eq!</span>( |
| <a href=#40 id=40 data-nosnippet>40</a> last_subtree_idx + last_subtree.usize_len() + <span class="number">1</span>, |
| <a href=#41 id=41 data-nosnippet>41</a> <span class="self">self</span>.index, |
| <a href=#42 id=42 data-nosnippet>42</a> <span class="string">"called `Cursor::end()` without finishing a subtree" |
| <a href=#43 id=43 data-nosnippet>43</a> </span>); |
| <a href=#44 id=44 data-nosnippet>44</a> <span class="self">self</span>.subtrees_stack.pop(); |
| <a href=#45 id=45 data-nosnippet>45</a> last_subtree |
| <a href=#46 id=46 data-nosnippet>46</a> } |
| <a href=#47 id=47 data-nosnippet>47</a> |
| <a href=#48 id=48 data-nosnippet>48</a> <span class="doccomment">/// Returns the `TokenTree` at the cursor if it is not at the end of a subtree. |
| <a href=#49 id=49 data-nosnippet>49</a> </span><span class="kw">pub fn </span>token_tree(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span><span class="lifetime">'a </span>TokenTree<Span>> { |
| <a href=#50 id=50 data-nosnippet>50</a> <span class="kw">if let </span><span class="prelude-val">Some</span>((last_subtree_idx, last_subtree)) = <span class="self">self</span>.last_subtree() { |
| <a href=#51 id=51 data-nosnippet>51</a> <span class="comment">// +1 because `Subtree.len` excludes the subtree itself. |
| <a href=#52 id=52 data-nosnippet>52</a> </span><span class="kw">if </span>last_subtree_idx + last_subtree.usize_len() + <span class="number">1 </span>== <span class="self">self</span>.index { |
| <a href=#53 id=53 data-nosnippet>53</a> <span class="kw">return </span><span class="prelude-val">None</span>; |
| <a href=#54 id=54 data-nosnippet>54</a> } |
| <a href=#55 id=55 data-nosnippet>55</a> } |
| <a href=#56 id=56 data-nosnippet>56</a> <span class="self">self</span>.buffer.get(<span class="self">self</span>.index) |
| <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="doccomment">/// Bump the cursor, and enters a subtree if it is on one. |
| <a href=#60 id=60 data-nosnippet>60</a> </span><span class="kw">pub fn </span>bump(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <a href=#61 id=61 data-nosnippet>61</a> <span class="kw">if let </span><span class="prelude-val">Some</span>((last_subtree_idx, last_subtree)) = <span class="self">self</span>.last_subtree() { |
| <a href=#62 id=62 data-nosnippet>62</a> <span class="comment">// +1 because `Subtree.len` excludes the subtree itself. |
| <a href=#63 id=63 data-nosnippet>63</a> </span><span class="macro">assert_ne!</span>( |
| <a href=#64 id=64 data-nosnippet>64</a> last_subtree_idx + last_subtree.usize_len() + <span class="number">1</span>, |
| <a href=#65 id=65 data-nosnippet>65</a> <span class="self">self</span>.index, |
| <a href=#66 id=66 data-nosnippet>66</a> <span class="string">"called `Cursor::bump()` when at the end of a subtree" |
| <a href=#67 id=67 data-nosnippet>67</a> </span>); |
| <a href=#68 id=68 data-nosnippet>68</a> } |
| <a href=#69 id=69 data-nosnippet>69</a> <span class="kw">if let </span>TokenTree::Subtree(<span class="kw">_</span>) = <span class="self">self</span>.buffer[<span class="self">self</span>.index] { |
| <a href=#70 id=70 data-nosnippet>70</a> <span class="self">self</span>.subtrees_stack.push(<span class="self">self</span>.index); |
| <a href=#71 id=71 data-nosnippet>71</a> } |
| <a href=#72 id=72 data-nosnippet>72</a> <span class="self">self</span>.index += <span class="number">1</span>; |
| <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> <span class="kw">pub fn </span>bump_or_end(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <a href=#76 id=76 data-nosnippet>76</a> <span class="kw">if let </span><span class="prelude-val">Some</span>((last_subtree_idx, last_subtree)) = <span class="self">self</span>.last_subtree() { |
| <a href=#77 id=77 data-nosnippet>77</a> <span class="comment">// +1 because `Subtree.len` excludes the subtree itself. |
| <a href=#78 id=78 data-nosnippet>78</a> </span><span class="kw">if </span>last_subtree_idx + last_subtree.usize_len() + <span class="number">1 </span>== <span class="self">self</span>.index { |
| <a href=#79 id=79 data-nosnippet>79</a> <span class="self">self</span>.subtrees_stack.pop(); |
| <a href=#80 id=80 data-nosnippet>80</a> <span class="kw">return</span>; |
| <a href=#81 id=81 data-nosnippet>81</a> } |
| <a href=#82 id=82 data-nosnippet>82</a> } |
| <a href=#83 id=83 data-nosnippet>83</a> <span class="comment">// +1 because `Subtree.len` excludes the subtree itself. |
| <a href=#84 id=84 data-nosnippet>84</a> </span><span class="kw">if let </span>TokenTree::Subtree(<span class="kw">_</span>) = <span class="self">self</span>.buffer[<span class="self">self</span>.index] { |
| <a href=#85 id=85 data-nosnippet>85</a> <span class="self">self</span>.subtrees_stack.push(<span class="self">self</span>.index); |
| <a href=#86 id=86 data-nosnippet>86</a> } |
| <a href=#87 id=87 data-nosnippet>87</a> <span class="self">self</span>.index += <span class="number">1</span>; |
| <a href=#88 id=88 data-nosnippet>88</a> } |
| <a href=#89 id=89 data-nosnippet>89</a> |
| <a href=#90 id=90 data-nosnippet>90</a> <span class="kw">pub fn </span>peek_two_leaves(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><[<span class="kw-2">&</span><span class="lifetime">'a </span>Leaf<Span>; <span class="number">2</span>]> { |
| <a href=#91 id=91 data-nosnippet>91</a> <span class="kw">if let </span><span class="prelude-val">Some</span>((last_subtree_idx, last_subtree)) = <span class="self">self</span>.last_subtree() { |
| <a href=#92 id=92 data-nosnippet>92</a> <span class="comment">// +1 because `Subtree.len` excludes the subtree itself. |
| <a href=#93 id=93 data-nosnippet>93</a> </span><span class="kw">let </span>last_end = last_subtree_idx + last_subtree.usize_len() + <span class="number">1</span>; |
| <a href=#94 id=94 data-nosnippet>94</a> <span class="kw">if </span>last_end == <span class="self">self</span>.index || last_end == <span class="self">self</span>.index + <span class="number">1 </span>{ |
| <a href=#95 id=95 data-nosnippet>95</a> <span class="kw">return </span><span class="prelude-val">None</span>; |
| <a href=#96 id=96 data-nosnippet>96</a> } |
| <a href=#97 id=97 data-nosnippet>97</a> } |
| <a href=#98 id=98 data-nosnippet>98</a> <span class="self">self</span>.buffer.get(<span class="self">self</span>.index..<span class="self">self</span>.index + <span class="number">2</span>).and_then(|it| <span class="kw">match </span>it { |
| <a href=#99 id=99 data-nosnippet>99</a> [TokenTree::Leaf(a), TokenTree::Leaf(b)] => <span class="prelude-val">Some</span>([a, b]), |
| <a href=#100 id=100 data-nosnippet>100</a> <span class="kw">_ </span>=> <span class="prelude-val">None</span>, |
| <a href=#101 id=101 data-nosnippet>101</a> }) |
| <a href=#102 id=102 data-nosnippet>102</a> } |
| <a href=#103 id=103 data-nosnippet>103</a> |
| <a href=#104 id=104 data-nosnippet>104</a> <span class="kw">pub fn </span>crossed(<span class="kw-2">&</span><span class="self">self</span>) -> TokenTreesView<<span class="lifetime">'a</span>, Span> { |
| <a href=#105 id=105 data-nosnippet>105</a> <span class="macro">assert!</span>(<span class="self">self</span>.is_root()); |
| <a href=#106 id=106 data-nosnippet>106</a> TokenTreesView::new(<span class="kw-2">&</span><span class="self">self</span>.buffer[..<span class="self">self</span>.index]) |
| <a href=#107 id=107 data-nosnippet>107</a> } |
| <a href=#108 id=108 data-nosnippet>108</a>}</code></pre></div></section></main></body></html> |
