| <!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/lib.rs`."><title>lib.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-aa0817cf.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="1.90.0 (1159e78c4 2025-09-14)" data-channel="1.90.0" data-search-js="search-fa3e91e5.js" data-settings-js="settings-5514c975.js" ><script src="../../static.files/storage-68b7e25d.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-eebb9057.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">syntax/</div>lib.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">//! Syntax Tree library used throughout the rust-analyzer. |
| <a href=#2 id=2 data-nosnippet>2</a>//! |
| <a href=#3 id=3 data-nosnippet>3</a>//! Properties: |
| <a href=#4 id=4 data-nosnippet>4</a>//! - easy and fast incremental re-parsing |
| <a href=#5 id=5 data-nosnippet>5</a>//! - graceful handling of errors |
| <a href=#6 id=6 data-nosnippet>6</a>//! - full-fidelity representation (*any* text can be precisely represented as |
| <a href=#7 id=7 data-nosnippet>7</a>//! a syntax tree) |
| <a href=#8 id=8 data-nosnippet>8</a>//! |
| <a href=#9 id=9 data-nosnippet>9</a>//! For more information, see the [RFC]. Current implementation is inspired by |
| <a href=#10 id=10 data-nosnippet>10</a>//! the [Swift] one. |
| <a href=#11 id=11 data-nosnippet>11</a>//! |
| <a href=#12 id=12 data-nosnippet>12</a>//! The most interesting modules here are `syntax_node` (which defines concrete |
| <a href=#13 id=13 data-nosnippet>13</a>//! syntax tree) and `ast` (which defines abstract syntax tree on top of the |
| <a href=#14 id=14 data-nosnippet>14</a>//! CST). The actual parser live in a separate `parser` crate, though the |
| <a href=#15 id=15 data-nosnippet>15</a>//! lexer lives in this crate. |
| <a href=#16 id=16 data-nosnippet>16</a>//! |
| <a href=#17 id=17 data-nosnippet>17</a>//! See `api_walkthrough` test in this file for a quick API tour! |
| <a href=#18 id=18 data-nosnippet>18</a>//! |
| <a href=#19 id=19 data-nosnippet>19</a>//! [RFC]: <https://github.com/rust-lang/rfcs/pull/2256> |
| <a href=#20 id=20 data-nosnippet>20</a>//! [Swift]: <https://github.com/apple/swift/blob/13d593df6f359d0cb2fc81cfaac273297c539455/lib/Syntax/README.md> |
| <a href=#21 id=21 data-nosnippet>21</a> |
| <a href=#22 id=22 data-nosnippet>22</a></span><span class="kw">mod </span>parsing; |
| <a href=#23 id=23 data-nosnippet>23</a><span class="kw">mod </span>ptr; |
| <a href=#24 id=24 data-nosnippet>24</a><span class="kw">mod </span>syntax_error; |
| <a href=#25 id=25 data-nosnippet>25</a><span class="kw">mod </span>syntax_node; |
| <a href=#26 id=26 data-nosnippet>26</a><span class="attr">#[cfg(test)] |
| <a href=#27 id=27 data-nosnippet>27</a></span><span class="kw">mod </span>tests; |
| <a href=#28 id=28 data-nosnippet>28</a><span class="kw">mod </span>token_text; |
| <a href=#29 id=29 data-nosnippet>29</a><span class="kw">mod </span>validation; |
| <a href=#30 id=30 data-nosnippet>30</a> |
| <a href=#31 id=31 data-nosnippet>31</a><span class="kw">pub mod </span>algo; |
| <a href=#32 id=32 data-nosnippet>32</a><span class="kw">pub mod </span>ast; |
| <a href=#33 id=33 data-nosnippet>33</a><span class="attr">#[doc(hidden)] |
| <a href=#34 id=34 data-nosnippet>34</a></span><span class="kw">pub mod </span>fuzz; |
| <a href=#35 id=35 data-nosnippet>35</a><span class="kw">pub mod </span>hacks; |
| <a href=#36 id=36 data-nosnippet>36</a><span class="kw">pub mod </span>syntax_editor; |
| <a href=#37 id=37 data-nosnippet>37</a><span class="kw">pub mod </span>ted; |
| <a href=#38 id=38 data-nosnippet>38</a><span class="kw">pub mod </span>utils; |
| <a href=#39 id=39 data-nosnippet>39</a> |
| <a href=#40 id=40 data-nosnippet>40</a><span class="kw">use </span>std::{marker::PhantomData, ops::Range}; |
| <a href=#41 id=41 data-nosnippet>41</a> |
| <a href=#42 id=42 data-nosnippet>42</a><span class="kw">use </span>stdx::format_to; |
| <a href=#43 id=43 data-nosnippet>43</a><span class="kw">use </span>triomphe::Arc; |
| <a href=#44 id=44 data-nosnippet>44</a> |
| <a href=#45 id=45 data-nosnippet>45</a><span class="kw">pub use crate</span>::{ |
| <a href=#46 id=46 data-nosnippet>46</a> ast::{AstNode, AstToken}, |
| <a href=#47 id=47 data-nosnippet>47</a> ptr::{AstPtr, SyntaxNodePtr}, |
| <a href=#48 id=48 data-nosnippet>48</a> syntax_error::SyntaxError, |
| <a href=#49 id=49 data-nosnippet>49</a> syntax_node::{ |
| <a href=#50 id=50 data-nosnippet>50</a> PreorderWithTokens, RustLanguage, SyntaxElement, SyntaxElementChildren, SyntaxNode, |
| <a href=#51 id=51 data-nosnippet>51</a> SyntaxNodeChildren, SyntaxToken, SyntaxTreeBuilder, |
| <a href=#52 id=52 data-nosnippet>52</a> }, |
| <a href=#53 id=53 data-nosnippet>53</a> token_text::TokenText, |
| <a href=#54 id=54 data-nosnippet>54</a>}; |
| <a href=#55 id=55 data-nosnippet>55</a><span class="kw">pub use </span>parser::{Edition, SyntaxKind, T}; |
| <a href=#56 id=56 data-nosnippet>56</a><span class="kw">pub use </span>rowan::{ |
| <a href=#57 id=57 data-nosnippet>57</a> Direction, GreenNode, NodeOrToken, SyntaxText, TextRange, TextSize, TokenAtOffset, WalkEvent, |
| <a href=#58 id=58 data-nosnippet>58</a> api::Preorder, |
| <a href=#59 id=59 data-nosnippet>59</a>}; |
| <a href=#60 id=60 data-nosnippet>60</a><span class="kw">pub use </span>rustc_literal_escaper <span class="kw">as </span>unescape; |
| <a href=#61 id=61 data-nosnippet>61</a><span class="kw">pub use </span>smol_str::{SmolStr, SmolStrBuilder, ToSmolStr, format_smolstr}; |
| <a href=#62 id=62 data-nosnippet>62</a> |
| <a href=#63 id=63 data-nosnippet>63</a><span class="doccomment">/// `Parse` is the result of the parsing: a syntax tree and a collection of |
| <a href=#64 id=64 data-nosnippet>64</a>/// errors. |
| <a href=#65 id=65 data-nosnippet>65</a>/// |
| <a href=#66 id=66 data-nosnippet>66</a>/// Note that we always produce a syntax tree, even for completely invalid |
| <a href=#67 id=67 data-nosnippet>67</a>/// files. |
| <a href=#68 id=68 data-nosnippet>68</a></span><span class="attr">#[derive(Debug, PartialEq, Eq)] |
| <a href=#69 id=69 data-nosnippet>69</a></span><span class="kw">pub struct </span>Parse<T> { |
| <a href=#70 id=70 data-nosnippet>70</a> green: GreenNode, |
| <a href=#71 id=71 data-nosnippet>71</a> errors: <span class="prelude-ty">Option</span><Arc<[SyntaxError]>>, |
| <a href=#72 id=72 data-nosnippet>72</a> _ty: PhantomData<<span class="kw">fn</span>() -> T>, |
| <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">impl</span><T> Clone <span class="kw">for </span>Parse<T> { |
| <a href=#76 id=76 data-nosnippet>76</a> <span class="kw">fn </span>clone(<span class="kw-2">&</span><span class="self">self</span>) -> Parse<T> { |
| <a href=#77 id=77 data-nosnippet>77</a> Parse { green: <span class="self">self</span>.green.clone(), errors: <span class="self">self</span>.errors.clone(), _ty: PhantomData } |
| <a href=#78 id=78 data-nosnippet>78</a> } |
| <a href=#79 id=79 data-nosnippet>79</a>} |
| <a href=#80 id=80 data-nosnippet>80</a> |
| <a href=#81 id=81 data-nosnippet>81</a><span class="kw">impl</span><T> Parse<T> { |
| <a href=#82 id=82 data-nosnippet>82</a> <span class="kw">fn </span>new(green: GreenNode, errors: Vec<SyntaxError>) -> Parse<T> { |
| <a href=#83 id=83 data-nosnippet>83</a> Parse { |
| <a href=#84 id=84 data-nosnippet>84</a> green, |
| <a href=#85 id=85 data-nosnippet>85</a> errors: <span class="kw">if </span>errors.is_empty() { <span class="prelude-val">None </span>} <span class="kw">else </span>{ <span class="prelude-val">Some</span>(errors.into()) }, |
| <a href=#86 id=86 data-nosnippet>86</a> _ty: PhantomData, |
| <a href=#87 id=87 data-nosnippet>87</a> } |
| <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>syntax_node(<span class="kw-2">&</span><span class="self">self</span>) -> SyntaxNode { |
| <a href=#91 id=91 data-nosnippet>91</a> SyntaxNode::new_root(<span class="self">self</span>.green.clone()) |
| <a href=#92 id=92 data-nosnippet>92</a> } |
| <a href=#93 id=93 data-nosnippet>93</a> |
| <a href=#94 id=94 data-nosnippet>94</a> <span class="kw">pub fn </span>errors(<span class="kw-2">&</span><span class="self">self</span>) -> Vec<SyntaxError> { |
| <a href=#95 id=95 data-nosnippet>95</a> <span class="kw">let </span><span class="kw-2">mut </span>errors = <span class="kw">if let </span><span class="prelude-val">Some</span>(e) = <span class="self">self</span>.errors.as_deref() { e.to_vec() } <span class="kw">else </span>{ <span class="macro">vec!</span>[] }; |
| <a href=#96 id=96 data-nosnippet>96</a> validation::validate(<span class="kw-2">&</span><span class="self">self</span>.syntax_node(), <span class="kw-2">&mut </span>errors); |
| <a href=#97 id=97 data-nosnippet>97</a> errors |
| <a href=#98 id=98 data-nosnippet>98</a> } |
| <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><span class="kw">impl</span><T: AstNode> Parse<T> { |
| <a href=#102 id=102 data-nosnippet>102</a> <span class="doccomment">/// Converts this parse result into a parse result for an untyped syntax tree. |
| <a href=#103 id=103 data-nosnippet>103</a> </span><span class="kw">pub fn </span>to_syntax(<span class="self">self</span>) -> Parse<SyntaxNode> { |
| <a href=#104 id=104 data-nosnippet>104</a> Parse { green: <span class="self">self</span>.green, errors: <span class="self">self</span>.errors, _ty: PhantomData } |
| <a href=#105 id=105 data-nosnippet>105</a> } |
| <a href=#106 id=106 data-nosnippet>106</a> |
| <a href=#107 id=107 data-nosnippet>107</a> <span class="doccomment">/// Gets the parsed syntax tree as a typed ast node. |
| <a href=#108 id=108 data-nosnippet>108</a> /// |
| <a href=#109 id=109 data-nosnippet>109</a> /// # Panics |
| <a href=#110 id=110 data-nosnippet>110</a> /// |
| <a href=#111 id=111 data-nosnippet>111</a> /// Panics if the root node cannot be casted into the typed ast node |
| <a href=#112 id=112 data-nosnippet>112</a> /// (e.g. if it's an `ERROR` node). |
| <a href=#113 id=113 data-nosnippet>113</a> </span><span class="kw">pub fn </span>tree(<span class="kw-2">&</span><span class="self">self</span>) -> T { |
| <a href=#114 id=114 data-nosnippet>114</a> T::cast(<span class="self">self</span>.syntax_node()).unwrap() |
| <a href=#115 id=115 data-nosnippet>115</a> } |
| <a href=#116 id=116 data-nosnippet>116</a> |
| <a href=#117 id=117 data-nosnippet>117</a> <span class="doccomment">/// Converts from `Parse<T>` to [`Result<T, Vec<SyntaxError>>`]. |
| <a href=#118 id=118 data-nosnippet>118</a> </span><span class="kw">pub fn </span>ok(<span class="self">self</span>) -> <span class="prelude-ty">Result</span><T, Vec<SyntaxError>> { |
| <a href=#119 id=119 data-nosnippet>119</a> <span class="kw">match </span><span class="self">self</span>.errors() { |
| <a href=#120 id=120 data-nosnippet>120</a> errors <span class="kw">if </span>!errors.is_empty() => <span class="prelude-val">Err</span>(errors), |
| <a href=#121 id=121 data-nosnippet>121</a> <span class="kw">_ </span>=> <span class="prelude-val">Ok</span>(<span class="self">self</span>.tree()), |
| <a href=#122 id=122 data-nosnippet>122</a> } |
| <a href=#123 id=123 data-nosnippet>123</a> } |
| <a href=#124 id=124 data-nosnippet>124</a>} |
| <a href=#125 id=125 data-nosnippet>125</a> |
| <a href=#126 id=126 data-nosnippet>126</a><span class="kw">impl </span>Parse<SyntaxNode> { |
| <a href=#127 id=127 data-nosnippet>127</a> <span class="kw">pub fn </span>cast<N: AstNode>(<span class="self">self</span>) -> <span class="prelude-ty">Option</span><Parse<N>> { |
| <a href=#128 id=128 data-nosnippet>128</a> <span class="kw">if </span>N::cast(<span class="self">self</span>.syntax_node()).is_some() { |
| <a href=#129 id=129 data-nosnippet>129</a> <span class="prelude-val">Some</span>(Parse { green: <span class="self">self</span>.green, errors: <span class="self">self</span>.errors, _ty: PhantomData }) |
| <a href=#130 id=130 data-nosnippet>130</a> } <span class="kw">else </span>{ |
| <a href=#131 id=131 data-nosnippet>131</a> <span class="prelude-val">None |
| <a href=#132 id=132 data-nosnippet>132</a> </span>} |
| <a href=#133 id=133 data-nosnippet>133</a> } |
| <a href=#134 id=134 data-nosnippet>134</a>} |
| <a href=#135 id=135 data-nosnippet>135</a> |
| <a href=#136 id=136 data-nosnippet>136</a><span class="kw">impl </span>Parse<SourceFile> { |
| <a href=#137 id=137 data-nosnippet>137</a> <span class="kw">pub fn </span>debug_dump(<span class="kw-2">&</span><span class="self">self</span>) -> String { |
| <a href=#138 id=138 data-nosnippet>138</a> <span class="kw">let </span><span class="kw-2">mut </span>buf = <span class="macro">format!</span>(<span class="string">"{:#?}"</span>, <span class="self">self</span>.tree().syntax()); |
| <a href=#139 id=139 data-nosnippet>139</a> <span class="kw">for </span>err <span class="kw">in </span><span class="self">self</span>.errors() { |
| <a href=#140 id=140 data-nosnippet>140</a> <span class="macro">format_to!</span>(buf, <span class="string">"error {:?}: {}\n"</span>, err.range(), err); |
| <a href=#141 id=141 data-nosnippet>141</a> } |
| <a href=#142 id=142 data-nosnippet>142</a> buf |
| <a href=#143 id=143 data-nosnippet>143</a> } |
| <a href=#144 id=144 data-nosnippet>144</a> |
| <a href=#145 id=145 data-nosnippet>145</a> <span class="kw">pub fn </span>reparse(<span class="kw-2">&</span><span class="self">self</span>, delete: TextRange, insert: <span class="kw-2">&</span>str, edition: Edition) -> Parse<SourceFile> { |
| <a href=#146 id=146 data-nosnippet>146</a> <span class="self">self</span>.incremental_reparse(delete, insert, edition) |
| <a href=#147 id=147 data-nosnippet>147</a> .unwrap_or_else(|| <span class="self">self</span>.full_reparse(delete, insert, edition)) |
| <a href=#148 id=148 data-nosnippet>148</a> } |
| <a href=#149 id=149 data-nosnippet>149</a> |
| <a href=#150 id=150 data-nosnippet>150</a> <span class="kw">fn </span>incremental_reparse( |
| <a href=#151 id=151 data-nosnippet>151</a> <span class="kw-2">&</span><span class="self">self</span>, |
| <a href=#152 id=152 data-nosnippet>152</a> delete: TextRange, |
| <a href=#153 id=153 data-nosnippet>153</a> insert: <span class="kw-2">&</span>str, |
| <a href=#154 id=154 data-nosnippet>154</a> edition: Edition, |
| <a href=#155 id=155 data-nosnippet>155</a> ) -> <span class="prelude-ty">Option</span><Parse<SourceFile>> { |
| <a href=#156 id=156 data-nosnippet>156</a> <span class="comment">// FIXME: validation errors are not handled here |
| <a href=#157 id=157 data-nosnippet>157</a> </span>parsing::incremental_reparse( |
| <a href=#158 id=158 data-nosnippet>158</a> <span class="self">self</span>.tree().syntax(), |
| <a href=#159 id=159 data-nosnippet>159</a> delete, |
| <a href=#160 id=160 data-nosnippet>160</a> insert, |
| <a href=#161 id=161 data-nosnippet>161</a> <span class="self">self</span>.errors.as_deref().unwrap_or_default().iter().cloned(), |
| <a href=#162 id=162 data-nosnippet>162</a> edition, |
| <a href=#163 id=163 data-nosnippet>163</a> ) |
| <a href=#164 id=164 data-nosnippet>164</a> .map(|(green_node, errors, _reparsed_range)| Parse { |
| <a href=#165 id=165 data-nosnippet>165</a> green: green_node, |
| <a href=#166 id=166 data-nosnippet>166</a> errors: <span class="kw">if </span>errors.is_empty() { <span class="prelude-val">None </span>} <span class="kw">else </span>{ <span class="prelude-val">Some</span>(errors.into()) }, |
| <a href=#167 id=167 data-nosnippet>167</a> _ty: PhantomData, |
| <a href=#168 id=168 data-nosnippet>168</a> }) |
| <a href=#169 id=169 data-nosnippet>169</a> } |
| <a href=#170 id=170 data-nosnippet>170</a> |
| <a href=#171 id=171 data-nosnippet>171</a> <span class="kw">fn </span>full_reparse(<span class="kw-2">&</span><span class="self">self</span>, delete: TextRange, insert: <span class="kw-2">&</span>str, edition: Edition) -> Parse<SourceFile> { |
| <a href=#172 id=172 data-nosnippet>172</a> <span class="kw">let </span><span class="kw-2">mut </span>text = <span class="self">self</span>.tree().syntax().text().to_string(); |
| <a href=#173 id=173 data-nosnippet>173</a> text.replace_range(Range::<usize>::from(delete), insert); |
| <a href=#174 id=174 data-nosnippet>174</a> SourceFile::parse(<span class="kw-2">&</span>text, edition) |
| <a href=#175 id=175 data-nosnippet>175</a> } |
| <a href=#176 id=176 data-nosnippet>176</a>} |
| <a href=#177 id=177 data-nosnippet>177</a> |
| <a href=#178 id=178 data-nosnippet>178</a><span class="kw">impl </span>ast::Expr { |
| <a href=#179 id=179 data-nosnippet>179</a> <span class="doccomment">/// Parses an `ast::Expr` from `text`. |
| <a href=#180 id=180 data-nosnippet>180</a> /// |
| <a href=#181 id=181 data-nosnippet>181</a> /// Note that if the parsed root node is not a valid expression, [`Parse::tree`] will panic. |
| <a href=#182 id=182 data-nosnippet>182</a> /// For example: |
| <a href=#183 id=183 data-nosnippet>183</a> /// ```rust,should_panic |
| <a href=#184 id=184 data-nosnippet>184</a> /// # use syntax::{ast, Edition}; |
| <a href=#185 id=185 data-nosnippet>185</a> /// ast::Expr::parse("let fail = true;", Edition::CURRENT).tree(); |
| <a href=#186 id=186 data-nosnippet>186</a> /// ``` |
| <a href=#187 id=187 data-nosnippet>187</a> </span><span class="kw">pub fn </span>parse(text: <span class="kw-2">&</span>str, edition: Edition) -> Parse<ast::Expr> { |
| <a href=#188 id=188 data-nosnippet>188</a> <span class="kw">let </span>_p = <span class="macro">tracing::info_span!</span>(<span class="string">"Expr::parse"</span>).entered(); |
| <a href=#189 id=189 data-nosnippet>189</a> <span class="kw">let </span>(green, errors) = parsing::parse_text_at(text, parser::TopEntryPoint::Expr, edition); |
| <a href=#190 id=190 data-nosnippet>190</a> <span class="kw">let </span>root = SyntaxNode::new_root(green.clone()); |
| <a href=#191 id=191 data-nosnippet>191</a> |
| <a href=#192 id=192 data-nosnippet>192</a> <span class="macro">assert!</span>( |
| <a href=#193 id=193 data-nosnippet>193</a> ast::Expr::can_cast(root.kind()) || root.kind() == SyntaxKind::ERROR, |
| <a href=#194 id=194 data-nosnippet>194</a> <span class="string">"{:?} isn't an expression"</span>, |
| <a href=#195 id=195 data-nosnippet>195</a> root.kind() |
| <a href=#196 id=196 data-nosnippet>196</a> ); |
| <a href=#197 id=197 data-nosnippet>197</a> Parse::new(green, errors) |
| <a href=#198 id=198 data-nosnippet>198</a> } |
| <a href=#199 id=199 data-nosnippet>199</a>} |
| <a href=#200 id=200 data-nosnippet>200</a> |
| <a href=#201 id=201 data-nosnippet>201</a><span class="doccomment">/// `SourceFile` represents a parse tree for a single Rust file. |
| <a href=#202 id=202 data-nosnippet>202</a></span><span class="kw">pub use </span><span class="kw">crate</span>::ast::SourceFile; |
| <a href=#203 id=203 data-nosnippet>203</a> |
| <a href=#204 id=204 data-nosnippet>204</a><span class="kw">impl </span>SourceFile { |
| <a href=#205 id=205 data-nosnippet>205</a> <span class="kw">pub fn </span>parse(text: <span class="kw-2">&</span>str, edition: Edition) -> Parse<SourceFile> { |
| <a href=#206 id=206 data-nosnippet>206</a> <span class="kw">let </span>_p = <span class="macro">tracing::info_span!</span>(<span class="string">"SourceFile::parse"</span>).entered(); |
| <a href=#207 id=207 data-nosnippet>207</a> <span class="kw">let </span>(green, errors) = parsing::parse_text(text, edition); |
| <a href=#208 id=208 data-nosnippet>208</a> <span class="kw">let </span>root = SyntaxNode::new_root(green.clone()); |
| <a href=#209 id=209 data-nosnippet>209</a> |
| <a href=#210 id=210 data-nosnippet>210</a> <span class="macro">assert_eq!</span>(root.kind(), SyntaxKind::SOURCE_FILE); |
| <a href=#211 id=211 data-nosnippet>211</a> Parse::new(green, errors) |
| <a href=#212 id=212 data-nosnippet>212</a> } |
| <a href=#213 id=213 data-nosnippet>213</a>} |
| <a href=#214 id=214 data-nosnippet>214</a> |
| <a href=#215 id=215 data-nosnippet>215</a><span class="doccomment">/// Matches a `SyntaxNode` against an `ast` type. |
| <a href=#216 id=216 data-nosnippet>216</a>/// |
| <a href=#217 id=217 data-nosnippet>217</a>/// # Example: |
| <a href=#218 id=218 data-nosnippet>218</a>/// |
| <a href=#219 id=219 data-nosnippet>219</a>/// ```ignore |
| <a href=#220 id=220 data-nosnippet>220</a>/// match_ast! { |
| <a href=#221 id=221 data-nosnippet>221</a>/// match node { |
| <a href=#222 id=222 data-nosnippet>222</a>/// ast::CallExpr(it) => { ... }, |
| <a href=#223 id=223 data-nosnippet>223</a>/// ast::MethodCallExpr(it) => { ... }, |
| <a href=#224 id=224 data-nosnippet>224</a>/// ast::MacroCall(it) => { ... }, |
| <a href=#225 id=225 data-nosnippet>225</a>/// _ => None, |
| <a href=#226 id=226 data-nosnippet>226</a>/// } |
| <a href=#227 id=227 data-nosnippet>227</a>/// } |
| <a href=#228 id=228 data-nosnippet>228</a>/// ``` |
| <a href=#229 id=229 data-nosnippet>229</a></span><span class="attr">#[macro_export] |
| <a href=#230 id=230 data-nosnippet>230</a></span><span class="macro">macro_rules!</span> match_ast { |
| <a href=#231 id=231 data-nosnippet>231</a> (<span class="kw">match </span><span class="macro-nonterminal">$node</span>:ident { $(<span class="macro-nonterminal">$tt</span>:tt)* }) => { <span class="macro-nonterminal">$</span><span class="macro">crate::match_ast!</span>(<span class="kw">match </span>(<span class="macro-nonterminal">$node</span>) { $(<span class="macro-nonterminal">$tt</span>)* }) }; |
| <a href=#232 id=232 data-nosnippet>232</a> |
| <a href=#233 id=233 data-nosnippet>233</a> (<span class="kw">match </span>(<span class="macro-nonterminal">$node</span>:expr) { |
| <a href=#234 id=234 data-nosnippet>234</a> $( $( <span class="macro-nonterminal">$path</span>:ident )::+ (<span class="macro-nonterminal">$it</span>:pat) => <span class="macro-nonterminal">$res</span>:expr, )* |
| <a href=#235 id=235 data-nosnippet>235</a> <span class="kw">_ </span>=> <span class="macro-nonterminal">$catch_all</span>:expr $(,)<span class="question-mark">? |
| <a href=#236 id=236 data-nosnippet>236</a> </span>}) => {{ |
| <a href=#237 id=237 data-nosnippet>237</a> $( <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="macro-nonterminal">$it</span>) = $(<span class="macro-nonterminal">$path</span>::)+cast(<span class="macro-nonterminal">$node</span>.clone()) { <span class="macro-nonterminal">$res </span>} <span class="kw">else </span>)* |
| <a href=#238 id=238 data-nosnippet>238</a> { <span class="macro-nonterminal">$catch_all </span>} |
| <a href=#239 id=239 data-nosnippet>239</a> }}; |
| <a href=#240 id=240 data-nosnippet>240</a>} |
| <a href=#241 id=241 data-nosnippet>241</a> |
| <a href=#242 id=242 data-nosnippet>242</a><span class="doccomment">/// This test does not assert anything and instead just shows off the crate's |
| <a href=#243 id=243 data-nosnippet>243</a>/// API. |
| <a href=#244 id=244 data-nosnippet>244</a></span><span class="attr">#[test] |
| <a href=#245 id=245 data-nosnippet>245</a></span><span class="kw">fn </span>api_walkthrough() { |
| <a href=#246 id=246 data-nosnippet>246</a> <span class="kw">use </span>ast::{HasModuleItem, HasName}; |
| <a href=#247 id=247 data-nosnippet>247</a> |
| <a href=#248 id=248 data-nosnippet>248</a> <span class="kw">let </span>source_code = <span class="string">" |
| <a href=#249 id=249 data-nosnippet>249</a> fn foo() { |
| <a href=#250 id=250 data-nosnippet>250</a> 1 + 1 |
| <a href=#251 id=251 data-nosnippet>251</a> } |
| <a href=#252 id=252 data-nosnippet>252</a> "</span>; |
| <a href=#253 id=253 data-nosnippet>253</a> <span class="comment">// `SourceFile` is the main entry point. |
| <a href=#254 id=254 data-nosnippet>254</a> // |
| <a href=#255 id=255 data-nosnippet>255</a> // The `parse` method returns a `Parse` -- a pair of syntax tree and a list |
| <a href=#256 id=256 data-nosnippet>256</a> // of errors. That is, syntax tree is constructed even in presence of errors. |
| <a href=#257 id=257 data-nosnippet>257</a> </span><span class="kw">let </span>parse = SourceFile::parse(source_code, parser::Edition::CURRENT); |
| <a href=#258 id=258 data-nosnippet>258</a> <span class="macro">assert!</span>(parse.errors().is_empty()); |
| <a href=#259 id=259 data-nosnippet>259</a> |
| <a href=#260 id=260 data-nosnippet>260</a> <span class="comment">// The `tree` method returns an owned syntax node of type `SourceFile`. |
| <a href=#261 id=261 data-nosnippet>261</a> // Owned nodes are cheap: inside, they are `Rc` handles to the underling data. |
| <a href=#262 id=262 data-nosnippet>262</a> </span><span class="kw">let </span>file: SourceFile = parse.tree(); |
| <a href=#263 id=263 data-nosnippet>263</a> |
| <a href=#264 id=264 data-nosnippet>264</a> <span class="comment">// `SourceFile` is the root of the syntax tree. We can iterate file's items. |
| <a href=#265 id=265 data-nosnippet>265</a> // Let's fetch the `foo` function. |
| <a href=#266 id=266 data-nosnippet>266</a> </span><span class="kw">let </span><span class="kw-2">mut </span>func = <span class="prelude-val">None</span>; |
| <a href=#267 id=267 data-nosnippet>267</a> <span class="kw">for </span>item <span class="kw">in </span>file.items() { |
| <a href=#268 id=268 data-nosnippet>268</a> <span class="kw">match </span>item { |
| <a href=#269 id=269 data-nosnippet>269</a> ast::Item::Fn(f) => func = <span class="prelude-val">Some</span>(f), |
| <a href=#270 id=270 data-nosnippet>270</a> <span class="kw">_ </span>=> <span class="macro">unreachable!</span>(), |
| <a href=#271 id=271 data-nosnippet>271</a> } |
| <a href=#272 id=272 data-nosnippet>272</a> } |
| <a href=#273 id=273 data-nosnippet>273</a> <span class="kw">let </span>func: ast::Fn = func.unwrap(); |
| <a href=#274 id=274 data-nosnippet>274</a> |
| <a href=#275 id=275 data-nosnippet>275</a> <span class="comment">// Each AST node has a bunch of getters for children. All getters return |
| <a href=#276 id=276 data-nosnippet>276</a> // `Option`s though, to account for incomplete code. Some getters are common |
| <a href=#277 id=277 data-nosnippet>277</a> // for several kinds of node. In this case, a trait like `ast::NameOwner` |
| <a href=#278 id=278 data-nosnippet>278</a> // usually exists. By convention, all ast types should be used with `ast::` |
| <a href=#279 id=279 data-nosnippet>279</a> // qualifier. |
| <a href=#280 id=280 data-nosnippet>280</a> </span><span class="kw">let </span>name: <span class="prelude-ty">Option</span><ast::Name> = func.name(); |
| <a href=#281 id=281 data-nosnippet>281</a> <span class="kw">let </span>name = name.unwrap(); |
| <a href=#282 id=282 data-nosnippet>282</a> <span class="macro">assert_eq!</span>(name.text(), <span class="string">"foo"</span>); |
| <a href=#283 id=283 data-nosnippet>283</a> |
| <a href=#284 id=284 data-nosnippet>284</a> <span class="comment">// Let's get the `1 + 1` expression! |
| <a href=#285 id=285 data-nosnippet>285</a> </span><span class="kw">let </span>body: ast::BlockExpr = func.body().unwrap(); |
| <a href=#286 id=286 data-nosnippet>286</a> <span class="kw">let </span>stmt_list: ast::StmtList = body.stmt_list().unwrap(); |
| <a href=#287 id=287 data-nosnippet>287</a> <span class="kw">let </span>expr: ast::Expr = stmt_list.tail_expr().unwrap(); |
| <a href=#288 id=288 data-nosnippet>288</a> |
| <a href=#289 id=289 data-nosnippet>289</a> <span class="comment">// Enums are used to group related ast nodes together, and can be used for |
| <a href=#290 id=290 data-nosnippet>290</a> // matching. However, because there are no public fields, it's possible to |
| <a href=#291 id=291 data-nosnippet>291</a> // match only the top level enum: that is the price we pay for increased API |
| <a href=#292 id=292 data-nosnippet>292</a> // flexibility |
| <a href=#293 id=293 data-nosnippet>293</a> </span><span class="kw">let </span>bin_expr: <span class="kw-2">&</span>ast::BinExpr = <span class="kw">match </span><span class="kw-2">&</span>expr { |
| <a href=#294 id=294 data-nosnippet>294</a> ast::Expr::BinExpr(e) => e, |
| <a href=#295 id=295 data-nosnippet>295</a> <span class="kw">_ </span>=> <span class="macro">unreachable!</span>(), |
| <a href=#296 id=296 data-nosnippet>296</a> }; |
| <a href=#297 id=297 data-nosnippet>297</a> |
| <a href=#298 id=298 data-nosnippet>298</a> <span class="comment">// Besides the "typed" AST API, there's an untyped CST one as well. |
| <a href=#299 id=299 data-nosnippet>299</a> // To switch from AST to CST, call `.syntax()` method: |
| <a href=#300 id=300 data-nosnippet>300</a> </span><span class="kw">let </span>expr_syntax: <span class="kw-2">&</span>SyntaxNode = expr.syntax(); |
| <a href=#301 id=301 data-nosnippet>301</a> |
| <a href=#302 id=302 data-nosnippet>302</a> <span class="comment">// Note how `expr` and `bin_expr` are in fact the same node underneath: |
| <a href=#303 id=303 data-nosnippet>303</a> </span><span class="macro">assert!</span>(expr_syntax == bin_expr.syntax()); |
| <a href=#304 id=304 data-nosnippet>304</a> |
| <a href=#305 id=305 data-nosnippet>305</a> <span class="comment">// To go from CST to AST, `AstNode::cast` function is used: |
| <a href=#306 id=306 data-nosnippet>306</a> </span><span class="kw">let </span>_expr: ast::Expr = <span class="kw">match </span>ast::Expr::cast(expr_syntax.clone()) { |
| <a href=#307 id=307 data-nosnippet>307</a> <span class="prelude-val">Some</span>(e) => e, |
| <a href=#308 id=308 data-nosnippet>308</a> <span class="prelude-val">None </span>=> <span class="macro">unreachable!</span>(), |
| <a href=#309 id=309 data-nosnippet>309</a> }; |
| <a href=#310 id=310 data-nosnippet>310</a> |
| <a href=#311 id=311 data-nosnippet>311</a> <span class="comment">// The two properties each syntax node has is a `SyntaxKind`: |
| <a href=#312 id=312 data-nosnippet>312</a> </span><span class="macro">assert_eq!</span>(expr_syntax.kind(), SyntaxKind::BIN_EXPR); |
| <a href=#313 id=313 data-nosnippet>313</a> |
| <a href=#314 id=314 data-nosnippet>314</a> <span class="comment">// And text range: |
| <a href=#315 id=315 data-nosnippet>315</a> </span><span class="macro">assert_eq!</span>(expr_syntax.text_range(), TextRange::new(<span class="number">32</span>.into(), <span class="number">37</span>.into())); |
| <a href=#316 id=316 data-nosnippet>316</a> |
| <a href=#317 id=317 data-nosnippet>317</a> <span class="comment">// You can get node's text as a `SyntaxText` object, which will traverse the |
| <a href=#318 id=318 data-nosnippet>318</a> // tree collecting token's text: |
| <a href=#319 id=319 data-nosnippet>319</a> </span><span class="kw">let </span>text: SyntaxText = expr_syntax.text(); |
| <a href=#320 id=320 data-nosnippet>320</a> <span class="macro">assert_eq!</span>(text.to_string(), <span class="string">"1 + 1"</span>); |
| <a href=#321 id=321 data-nosnippet>321</a> |
| <a href=#322 id=322 data-nosnippet>322</a> <span class="comment">// There's a bunch of traversal methods on `SyntaxNode`: |
| <a href=#323 id=323 data-nosnippet>323</a> </span><span class="macro">assert_eq!</span>(expr_syntax.parent().as_ref(), <span class="prelude-val">Some</span>(stmt_list.syntax())); |
| <a href=#324 id=324 data-nosnippet>324</a> <span class="macro">assert_eq!</span>(stmt_list.syntax().first_child_or_token().map(|it| it.kind()), <span class="prelude-val">Some</span>(<span class="macro">T!</span>[<span class="string">'{'</span>])); |
| <a href=#325 id=325 data-nosnippet>325</a> <span class="macro">assert_eq!</span>( |
| <a href=#326 id=326 data-nosnippet>326</a> expr_syntax.next_sibling_or_token().map(|it| it.kind()), |
| <a href=#327 id=327 data-nosnippet>327</a> <span class="prelude-val">Some</span>(SyntaxKind::WHITESPACE) |
| <a href=#328 id=328 data-nosnippet>328</a> ); |
| <a href=#329 id=329 data-nosnippet>329</a> |
| <a href=#330 id=330 data-nosnippet>330</a> <span class="comment">// As well as some iterator helpers: |
| <a href=#331 id=331 data-nosnippet>331</a> </span><span class="kw">let </span>f = expr_syntax.ancestors().find_map(ast::Fn::cast); |
| <a href=#332 id=332 data-nosnippet>332</a> <span class="macro">assert_eq!</span>(f, <span class="prelude-val">Some</span>(func)); |
| <a href=#333 id=333 data-nosnippet>333</a> <span class="macro">assert!</span>(expr_syntax.siblings_with_tokens(Direction::Next).any(|it| it.kind() == <span class="macro">T!</span>[<span class="string">'}'</span>])); |
| <a href=#334 id=334 data-nosnippet>334</a> <span class="macro">assert_eq!</span>( |
| <a href=#335 id=335 data-nosnippet>335</a> expr_syntax.descendants_with_tokens().count(), |
| <a href=#336 id=336 data-nosnippet>336</a> <span class="number">8</span>, <span class="comment">// 5 tokens `1`, ` `, `+`, ` `, `1` |
| <a href=#337 id=337 data-nosnippet>337</a> // 2 child literal expressions: `1`, `1` |
| <a href=#338 id=338 data-nosnippet>338</a> // 1 the node itself: `1 + 1` |
| <a href=#339 id=339 data-nosnippet>339</a> </span>); |
| <a href=#340 id=340 data-nosnippet>340</a> |
| <a href=#341 id=341 data-nosnippet>341</a> <span class="comment">// There's also a `preorder` method with a more fine-grained iteration control: |
| <a href=#342 id=342 data-nosnippet>342</a> </span><span class="kw">let </span><span class="kw-2">mut </span>buf = String::new(); |
| <a href=#343 id=343 data-nosnippet>343</a> <span class="kw">let </span><span class="kw-2">mut </span>indent = <span class="number">0</span>; |
| <a href=#344 id=344 data-nosnippet>344</a> <span class="kw">for </span>event <span class="kw">in </span>expr_syntax.preorder_with_tokens() { |
| <a href=#345 id=345 data-nosnippet>345</a> <span class="kw">match </span>event { |
| <a href=#346 id=346 data-nosnippet>346</a> WalkEvent::Enter(node) => { |
| <a href=#347 id=347 data-nosnippet>347</a> <span class="kw">let </span>text = <span class="kw">match </span><span class="kw-2">&</span>node { |
| <a href=#348 id=348 data-nosnippet>348</a> NodeOrToken::Node(it) => it.text().to_string(), |
| <a href=#349 id=349 data-nosnippet>349</a> NodeOrToken::Token(it) => it.text().to_owned(), |
| <a href=#350 id=350 data-nosnippet>350</a> }; |
| <a href=#351 id=351 data-nosnippet>351</a> <span class="macro">format_to!</span>(buf, <span class="string">"{:indent$}{:?} {:?}\n"</span>, <span class="string">" "</span>, text, node.kind(), indent = indent); |
| <a href=#352 id=352 data-nosnippet>352</a> indent += <span class="number">2</span>; |
| <a href=#353 id=353 data-nosnippet>353</a> } |
| <a href=#354 id=354 data-nosnippet>354</a> WalkEvent::Leave(<span class="kw">_</span>) => indent -= <span class="number">2</span>, |
| <a href=#355 id=355 data-nosnippet>355</a> } |
| <a href=#356 id=356 data-nosnippet>356</a> } |
| <a href=#357 id=357 data-nosnippet>357</a> <span class="macro">assert_eq!</span>(indent, <span class="number">0</span>); |
| <a href=#358 id=358 data-nosnippet>358</a> <span class="macro">assert_eq!</span>( |
| <a href=#359 id=359 data-nosnippet>359</a> buf.trim(), |
| <a href=#360 id=360 data-nosnippet>360</a> <span class="string">r#" |
| <a href=#361 id=361 data-nosnippet>361</a>"1 + 1" BIN_EXPR |
| <a href=#362 id=362 data-nosnippet>362</a> "1" LITERAL |
| <a href=#363 id=363 data-nosnippet>363</a> "1" INT_NUMBER |
| <a href=#364 id=364 data-nosnippet>364</a> " " WHITESPACE |
| <a href=#365 id=365 data-nosnippet>365</a> "+" PLUS |
| <a href=#366 id=366 data-nosnippet>366</a> " " WHITESPACE |
| <a href=#367 id=367 data-nosnippet>367</a> "1" LITERAL |
| <a href=#368 id=368 data-nosnippet>368</a> "1" INT_NUMBER |
| <a href=#369 id=369 data-nosnippet>369</a>"# |
| <a href=#370 id=370 data-nosnippet>370</a> </span>.trim() |
| <a href=#371 id=371 data-nosnippet>371</a> ); |
| <a href=#372 id=372 data-nosnippet>372</a> |
| <a href=#373 id=373 data-nosnippet>373</a> <span class="comment">// To recursively process the tree, there are three approaches: |
| <a href=#374 id=374 data-nosnippet>374</a> // 1. explicitly call getter methods on AST nodes. |
| <a href=#375 id=375 data-nosnippet>375</a> // 2. use descendants and `AstNode::cast`. |
| <a href=#376 id=376 data-nosnippet>376</a> // 3. use descendants and `match_ast!`. |
| <a href=#377 id=377 data-nosnippet>377</a> // |
| <a href=#378 id=378 data-nosnippet>378</a> // Here's how the first one looks like: |
| <a href=#379 id=379 data-nosnippet>379</a> </span><span class="kw">let </span>exprs_cast: Vec<String> = file |
| <a href=#380 id=380 data-nosnippet>380</a> .syntax() |
| <a href=#381 id=381 data-nosnippet>381</a> .descendants() |
| <a href=#382 id=382 data-nosnippet>382</a> .filter_map(ast::Expr::cast) |
| <a href=#383 id=383 data-nosnippet>383</a> .map(|expr| expr.syntax().text().to_string()) |
| <a href=#384 id=384 data-nosnippet>384</a> .collect(); |
| <a href=#385 id=385 data-nosnippet>385</a> |
| <a href=#386 id=386 data-nosnippet>386</a> <span class="comment">// An alternative is to use a macro. |
| <a href=#387 id=387 data-nosnippet>387</a> </span><span class="kw">let </span><span class="kw-2">mut </span>exprs_visit = Vec::new(); |
| <a href=#388 id=388 data-nosnippet>388</a> <span class="kw">for </span>node <span class="kw">in </span>file.syntax().descendants() { |
| <a href=#389 id=389 data-nosnippet>389</a> <span class="macro">match_ast!</span> { |
| <a href=#390 id=390 data-nosnippet>390</a> <span class="kw">match </span>node { |
| <a href=#391 id=391 data-nosnippet>391</a> ast::Expr(it) => { |
| <a href=#392 id=392 data-nosnippet>392</a> <span class="kw">let </span>res = it.syntax().text().to_string(); |
| <a href=#393 id=393 data-nosnippet>393</a> exprs_visit.push(res); |
| <a href=#394 id=394 data-nosnippet>394</a> }, |
| <a href=#395 id=395 data-nosnippet>395</a> <span class="kw">_ </span>=> (), |
| <a href=#396 id=396 data-nosnippet>396</a> } |
| <a href=#397 id=397 data-nosnippet>397</a> } |
| <a href=#398 id=398 data-nosnippet>398</a> } |
| <a href=#399 id=399 data-nosnippet>399</a> <span class="macro">assert_eq!</span>(exprs_cast, exprs_visit); |
| <a href=#400 id=400 data-nosnippet>400</a>}</code></pre></div></section></main></body></html> |
