| <!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/mbe/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="mbe" 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">mbe/</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">//! `mbe` (short for Macro By Example) crate contains code for handling |
| <a href=#2 id=2 data-nosnippet>2</a>//! `macro_rules` macros. It uses `TokenTree` (from `tt` package) as the |
| <a href=#3 id=3 data-nosnippet>3</a>//! interface, although it contains some code to bridge `SyntaxNode`s and |
| <a href=#4 id=4 data-nosnippet>4</a>//! `TokenTree`s as well! |
| <a href=#5 id=5 data-nosnippet>5</a>//! |
| <a href=#6 id=6 data-nosnippet>6</a>//! The tests for this functionality live in another crate: |
| <a href=#7 id=7 data-nosnippet>7</a>//! `hir_def::macro_expansion_tests::mbe`. |
| <a href=#8 id=8 data-nosnippet>8</a> |
| <a href=#9 id=9 data-nosnippet>9</a></span><span class="attr">#![cfg_attr(feature = <span class="string">"in-rust-tree"</span>, feature(rustc_private))] |
| <a href=#10 id=10 data-nosnippet>10</a> |
| <a href=#11 id=11 data-nosnippet>11</a>#[cfg(not(feature = <span class="string">"in-rust-tree"</span>))] |
| <a href=#12 id=12 data-nosnippet>12</a></span><span class="kw">extern crate </span>ra_ap_rustc_lexer <span class="kw">as </span>rustc_lexer; |
| <a href=#13 id=13 data-nosnippet>13</a><span class="attr">#[cfg(feature = <span class="string">"in-rust-tree"</span>)] |
| <a href=#14 id=14 data-nosnippet>14</a></span><span class="kw">extern crate </span>rustc_lexer; |
| <a href=#15 id=15 data-nosnippet>15</a> |
| <a href=#16 id=16 data-nosnippet>16</a><span class="kw">mod </span>expander; |
| <a href=#17 id=17 data-nosnippet>17</a><span class="kw">mod </span>parser; |
| <a href=#18 id=18 data-nosnippet>18</a> |
| <a href=#19 id=19 data-nosnippet>19</a><span class="attr">#[cfg(test)] |
| <a href=#20 id=20 data-nosnippet>20</a></span><span class="kw">mod </span>benchmark; |
| <a href=#21 id=21 data-nosnippet>21</a><span class="attr">#[cfg(test)] |
| <a href=#22 id=22 data-nosnippet>22</a></span><span class="kw">mod </span>tests; |
| <a href=#23 id=23 data-nosnippet>23</a> |
| <a href=#24 id=24 data-nosnippet>24</a><span class="kw">use </span>span::{Edition, Span, SyntaxContext}; |
| <a href=#25 id=25 data-nosnippet>25</a><span class="kw">use </span>syntax_bridge::to_parser_input; |
| <a href=#26 id=26 data-nosnippet>26</a><span class="kw">use </span>tt::DelimSpan; |
| <a href=#27 id=27 data-nosnippet>27</a><span class="kw">use </span>tt::iter::TtIter; |
| <a href=#28 id=28 data-nosnippet>28</a> |
| <a href=#29 id=29 data-nosnippet>29</a><span class="kw">use </span>std::fmt; |
| <a href=#30 id=30 data-nosnippet>30</a><span class="kw">use </span>std::sync::Arc; |
| <a href=#31 id=31 data-nosnippet>31</a> |
| <a href=#32 id=32 data-nosnippet>32</a><span class="kw">use </span><span class="kw">crate</span>::parser::{MetaTemplate, MetaVarKind, Op}; |
| <a href=#33 id=33 data-nosnippet>33</a> |
| <a href=#34 id=34 data-nosnippet>34</a><span class="kw">pub use </span>tt::{Delimiter, DelimiterKind, Punct}; |
| <a href=#35 id=35 data-nosnippet>35</a> |
| <a href=#36 id=36 data-nosnippet>36</a><span class="attr">#[derive(Debug, PartialEq, Eq, Clone)] |
| <a href=#37 id=37 data-nosnippet>37</a></span><span class="kw">pub enum </span>ParseError { |
| <a href=#38 id=38 data-nosnippet>38</a> UnexpectedToken(Box<str>), |
| <a href=#39 id=39 data-nosnippet>39</a> Expected(Box<str>), |
| <a href=#40 id=40 data-nosnippet>40</a> InvalidRepeat, |
| <a href=#41 id=41 data-nosnippet>41</a> RepetitionEmptyTokenTree, |
| <a href=#42 id=42 data-nosnippet>42</a>} |
| <a href=#43 id=43 data-nosnippet>43</a> |
| <a href=#44 id=44 data-nosnippet>44</a><span class="kw">impl </span>ParseError { |
| <a href=#45 id=45 data-nosnippet>45</a> <span class="kw">fn </span>expected(e: <span class="kw-2">&</span>str) -> ParseError { |
| <a href=#46 id=46 data-nosnippet>46</a> ParseError::Expected(e.into()) |
| <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="kw">fn </span>unexpected(e: <span class="kw-2">&</span>str) -> ParseError { |
| <a href=#50 id=50 data-nosnippet>50</a> ParseError::UnexpectedToken(e.into()) |
| <a href=#51 id=51 data-nosnippet>51</a> } |
| <a href=#52 id=52 data-nosnippet>52</a>} |
| <a href=#53 id=53 data-nosnippet>53</a> |
| <a href=#54 id=54 data-nosnippet>54</a><span class="kw">impl </span>fmt::Display <span class="kw">for </span>ParseError { |
| <a href=#55 id=55 data-nosnippet>55</a> <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| <a href=#56 id=56 data-nosnippet>56</a> <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#57 id=57 data-nosnippet>57</a> ParseError::UnexpectedToken(it) => f.write_str(it), |
| <a href=#58 id=58 data-nosnippet>58</a> ParseError::Expected(it) => f.write_str(it), |
| <a href=#59 id=59 data-nosnippet>59</a> ParseError::InvalidRepeat => f.write_str(<span class="string">"invalid repeat"</span>), |
| <a href=#60 id=60 data-nosnippet>60</a> ParseError::RepetitionEmptyTokenTree => f.write_str(<span class="string">"empty token tree in repetition"</span>), |
| <a href=#61 id=61 data-nosnippet>61</a> } |
| <a href=#62 id=62 data-nosnippet>62</a> } |
| <a href=#63 id=63 data-nosnippet>63</a>} |
| <a href=#64 id=64 data-nosnippet>64</a> |
| <a href=#65 id=65 data-nosnippet>65</a><span class="attr">#[derive(Debug, PartialEq, Eq, Clone, Hash)] |
| <a href=#66 id=66 data-nosnippet>66</a></span><span class="kw">pub struct </span>ExpandError { |
| <a href=#67 id=67 data-nosnippet>67</a> <span class="kw">pub </span>inner: Arc<(Span, ExpandErrorKind)>, |
| <a href=#68 id=68 data-nosnippet>68</a>} |
| <a href=#69 id=69 data-nosnippet>69</a><span class="attr">#[derive(Debug, PartialEq, Eq, Clone, Hash)] |
| <a href=#70 id=70 data-nosnippet>70</a></span><span class="kw">pub enum </span>ExpandErrorKind { |
| <a href=#71 id=71 data-nosnippet>71</a> BindingError(Box<Box<str>>), |
| <a href=#72 id=72 data-nosnippet>72</a> UnresolvedBinding(Box<Box<str>>), |
| <a href=#73 id=73 data-nosnippet>73</a> LeftoverTokens, |
| <a href=#74 id=74 data-nosnippet>74</a> LimitExceeded, |
| <a href=#75 id=75 data-nosnippet>75</a> NoMatchingRule, |
| <a href=#76 id=76 data-nosnippet>76</a> UnexpectedToken, |
| <a href=#77 id=77 data-nosnippet>77</a>} |
| <a href=#78 id=78 data-nosnippet>78</a> |
| <a href=#79 id=79 data-nosnippet>79</a><span class="kw">impl </span>ExpandError { |
| <a href=#80 id=80 data-nosnippet>80</a> <span class="kw">fn </span>new(span: Span, kind: ExpandErrorKind) -> ExpandError { |
| <a href=#81 id=81 data-nosnippet>81</a> ExpandError { inner: Arc::new((span, kind)) } |
| <a href=#82 id=82 data-nosnippet>82</a> } |
| <a href=#83 id=83 data-nosnippet>83</a> <span class="kw">fn </span>binding_error(span: Span, e: <span class="kw">impl </span>Into<Box<str>>) -> ExpandError { |
| <a href=#84 id=84 data-nosnippet>84</a> ExpandError { inner: Arc::new((span, ExpandErrorKind::BindingError(Box::new(e.into())))) } |
| <a href=#85 id=85 data-nosnippet>85</a> } |
| <a href=#86 id=86 data-nosnippet>86</a>} |
| <a href=#87 id=87 data-nosnippet>87</a><span class="kw">impl </span>fmt::Display <span class="kw">for </span>ExpandError { |
| <a href=#88 id=88 data-nosnippet>88</a> <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| <a href=#89 id=89 data-nosnippet>89</a> <span class="self">self</span>.inner.<span class="number">1</span>.fmt(f) |
| <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> |
| <a href=#93 id=93 data-nosnippet>93</a><span class="kw">impl </span>fmt::Display <span class="kw">for </span>ExpandErrorKind { |
| <a href=#94 id=94 data-nosnippet>94</a> <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| <a href=#95 id=95 data-nosnippet>95</a> <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#96 id=96 data-nosnippet>96</a> ExpandErrorKind::NoMatchingRule => f.write_str(<span class="string">"no rule matches input tokens"</span>), |
| <a href=#97 id=97 data-nosnippet>97</a> ExpandErrorKind::UnexpectedToken => f.write_str(<span class="string">"unexpected token in input"</span>), |
| <a href=#98 id=98 data-nosnippet>98</a> ExpandErrorKind::BindingError(e) => f.write_str(e), |
| <a href=#99 id=99 data-nosnippet>99</a> ExpandErrorKind::UnresolvedBinding(binding) => { |
| <a href=#100 id=100 data-nosnippet>100</a> f.write_str(<span class="string">"could not find binding "</span>)<span class="question-mark">?</span>; |
| <a href=#101 id=101 data-nosnippet>101</a> f.write_str(binding) |
| <a href=#102 id=102 data-nosnippet>102</a> } |
| <a href=#103 id=103 data-nosnippet>103</a> ExpandErrorKind::LimitExceeded => f.write_str(<span class="string">"Expand exceed limit"</span>), |
| <a href=#104 id=104 data-nosnippet>104</a> ExpandErrorKind::LeftoverTokens => f.write_str(<span class="string">"leftover tokens"</span>), |
| <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>} |
| <a href=#108 id=108 data-nosnippet>108</a> |
| <a href=#109 id=109 data-nosnippet>109</a><span class="comment">// FIXME: Showing these errors could be nicer. |
| <a href=#110 id=110 data-nosnippet>110</a></span><span class="attr">#[derive(Debug, PartialEq, Eq, Clone, Hash)] |
| <a href=#111 id=111 data-nosnippet>111</a></span><span class="kw">pub enum </span>CountError { |
| <a href=#112 id=112 data-nosnippet>112</a> OutOfBounds, |
| <a href=#113 id=113 data-nosnippet>113</a> Misplaced, |
| <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">impl </span>fmt::Display <span class="kw">for </span>CountError { |
| <a href=#117 id=117 data-nosnippet>117</a> <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| <a href=#118 id=118 data-nosnippet>118</a> <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#119 id=119 data-nosnippet>119</a> CountError::OutOfBounds => f.write_str(<span class="string">"${count} out of bounds"</span>), |
| <a href=#120 id=120 data-nosnippet>120</a> CountError::Misplaced => f.write_str(<span class="string">"${count} misplaced"</span>), |
| <a href=#121 id=121 data-nosnippet>121</a> } |
| <a href=#122 id=122 data-nosnippet>122</a> } |
| <a href=#123 id=123 data-nosnippet>123</a>} |
| <a href=#124 id=124 data-nosnippet>124</a> |
| <a href=#125 id=125 data-nosnippet>125</a><span class="doccomment">/// Index of the matched macro arm on successful expansion. |
| <a href=#126 id=126 data-nosnippet>126</a></span><span class="kw">pub type </span>MatchedArmIndex = <span class="prelude-ty">Option</span><u32>; |
| <a href=#127 id=127 data-nosnippet>127</a> |
| <a href=#128 id=128 data-nosnippet>128</a><span class="doccomment">/// This struct contains AST for a single `macro_rules` definition. What might |
| <a href=#129 id=129 data-nosnippet>129</a>/// be very confusing is that AST has almost exactly the same shape as |
| <a href=#130 id=130 data-nosnippet>130</a>/// `tt::TokenTree`, but there's a crucial difference: in macro rules, `$ident` |
| <a href=#131 id=131 data-nosnippet>131</a>/// and `$()*` have special meaning (see `Var` and `Repeat` data structures) |
| <a href=#132 id=132 data-nosnippet>132</a></span><span class="attr">#[derive(Clone, Debug, PartialEq, Eq)] |
| <a href=#133 id=133 data-nosnippet>133</a></span><span class="kw">pub struct </span>DeclarativeMacro { |
| <a href=#134 id=134 data-nosnippet>134</a> rules: Box<[Rule]>, |
| <a href=#135 id=135 data-nosnippet>135</a> err: <span class="prelude-ty">Option</span><Box<ParseError>>, |
| <a href=#136 id=136 data-nosnippet>136</a>} |
| <a href=#137 id=137 data-nosnippet>137</a> |
| <a href=#138 id=138 data-nosnippet>138</a><span class="attr">#[derive(Clone, Debug, PartialEq, Eq)] |
| <a href=#139 id=139 data-nosnippet>139</a></span><span class="kw">struct </span>Rule { |
| <a href=#140 id=140 data-nosnippet>140</a> lhs: MetaTemplate, |
| <a href=#141 id=141 data-nosnippet>141</a> rhs: MetaTemplate, |
| <a href=#142 id=142 data-nosnippet>142</a>} |
| <a href=#143 id=143 data-nosnippet>143</a> |
| <a href=#144 id=144 data-nosnippet>144</a><span class="kw">impl </span>DeclarativeMacro { |
| <a href=#145 id=145 data-nosnippet>145</a> <span class="kw">pub fn </span>from_err(err: ParseError) -> DeclarativeMacro { |
| <a href=#146 id=146 data-nosnippet>146</a> DeclarativeMacro { rules: Box::default(), err: <span class="prelude-val">Some</span>(Box::new(err)) } |
| <a href=#147 id=147 data-nosnippet>147</a> } |
| <a href=#148 id=148 data-nosnippet>148</a> |
| <a href=#149 id=149 data-nosnippet>149</a> <span class="doccomment">/// The old, `macro_rules! m {}` flavor. |
| <a href=#150 id=150 data-nosnippet>150</a> </span><span class="kw">pub fn </span>parse_macro_rules( |
| <a href=#151 id=151 data-nosnippet>151</a> tt: <span class="kw-2">&</span>tt::TopSubtree<Span>, |
| <a href=#152 id=152 data-nosnippet>152</a> ctx_edition: <span class="kw">impl </span>Copy + Fn(SyntaxContext) -> Edition, |
| <a href=#153 id=153 data-nosnippet>153</a> ) -> DeclarativeMacro { |
| <a href=#154 id=154 data-nosnippet>154</a> <span class="comment">// Note: this parsing can be implemented using mbe machinery itself, by |
| <a href=#155 id=155 data-nosnippet>155</a> // matching against `$($lhs:tt => $rhs:tt);*` pattern, but implementing |
| <a href=#156 id=156 data-nosnippet>156</a> // manually seems easier. |
| <a href=#157 id=157 data-nosnippet>157</a> </span><span class="kw">let </span><span class="kw-2">mut </span>src = tt.iter(); |
| <a href=#158 id=158 data-nosnippet>158</a> <span class="kw">let </span><span class="kw-2">mut </span>rules = Vec::new(); |
| <a href=#159 id=159 data-nosnippet>159</a> <span class="kw">let </span><span class="kw-2">mut </span>err = <span class="prelude-val">None</span>; |
| <a href=#160 id=160 data-nosnippet>160</a> |
| <a href=#161 id=161 data-nosnippet>161</a> <span class="kw">while </span>!src.is_empty() { |
| <a href=#162 id=162 data-nosnippet>162</a> <span class="kw">let </span>rule = <span class="kw">match </span>Rule::parse(ctx_edition, <span class="kw-2">&mut </span>src) { |
| <a href=#163 id=163 data-nosnippet>163</a> <span class="prelude-val">Ok</span>(it) => it, |
| <a href=#164 id=164 data-nosnippet>164</a> <span class="prelude-val">Err</span>(e) => { |
| <a href=#165 id=165 data-nosnippet>165</a> err = <span class="prelude-val">Some</span>(Box::new(e)); |
| <a href=#166 id=166 data-nosnippet>166</a> <span class="kw">break</span>; |
| <a href=#167 id=167 data-nosnippet>167</a> } |
| <a href=#168 id=168 data-nosnippet>168</a> }; |
| <a href=#169 id=169 data-nosnippet>169</a> rules.push(rule); |
| <a href=#170 id=170 data-nosnippet>170</a> <span class="kw">if let </span><span class="prelude-val">Err</span>(()) = src.expect_char(<span class="string">';'</span>) { |
| <a href=#171 id=171 data-nosnippet>171</a> <span class="kw">if </span>!src.is_empty() { |
| <a href=#172 id=172 data-nosnippet>172</a> err = <span class="prelude-val">Some</span>(Box::new(ParseError::expected(<span class="string">"expected `;`"</span>))); |
| <a href=#173 id=173 data-nosnippet>173</a> } |
| <a href=#174 id=174 data-nosnippet>174</a> <span class="kw">break</span>; |
| <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">for </span>Rule { lhs, .. } <span class="kw">in </span><span class="kw-2">&</span>rules { |
| <a href=#179 id=179 data-nosnippet>179</a> <span class="kw">if let </span><span class="prelude-val">Err</span>(e) = validate(lhs) { |
| <a href=#180 id=180 data-nosnippet>180</a> err = <span class="prelude-val">Some</span>(Box::new(e)); |
| <a href=#181 id=181 data-nosnippet>181</a> <span class="kw">break</span>; |
| <a href=#182 id=182 data-nosnippet>182</a> } |
| <a href=#183 id=183 data-nosnippet>183</a> } |
| <a href=#184 id=184 data-nosnippet>184</a> |
| <a href=#185 id=185 data-nosnippet>185</a> DeclarativeMacro { rules: rules.into_boxed_slice(), err } |
| <a href=#186 id=186 data-nosnippet>186</a> } |
| <a href=#187 id=187 data-nosnippet>187</a> |
| <a href=#188 id=188 data-nosnippet>188</a> <span class="doccomment">/// The new, unstable `macro m {}` flavor. |
| <a href=#189 id=189 data-nosnippet>189</a> </span><span class="kw">pub fn </span>parse_macro2( |
| <a href=#190 id=190 data-nosnippet>190</a> args: <span class="prelude-ty">Option</span><<span class="kw-2">&</span>tt::TopSubtree<Span>>, |
| <a href=#191 id=191 data-nosnippet>191</a> body: <span class="kw-2">&</span>tt::TopSubtree<Span>, |
| <a href=#192 id=192 data-nosnippet>192</a> ctx_edition: <span class="kw">impl </span>Copy + Fn(SyntaxContext) -> Edition, |
| <a href=#193 id=193 data-nosnippet>193</a> ) -> DeclarativeMacro { |
| <a href=#194 id=194 data-nosnippet>194</a> <span class="kw">let </span><span class="kw-2">mut </span>rules = Vec::new(); |
| <a href=#195 id=195 data-nosnippet>195</a> <span class="kw">let </span><span class="kw-2">mut </span>err = <span class="prelude-val">None</span>; |
| <a href=#196 id=196 data-nosnippet>196</a> |
| <a href=#197 id=197 data-nosnippet>197</a> <span class="kw">if let </span><span class="prelude-val">Some</span>(args) = args { |
| <a href=#198 id=198 data-nosnippet>198</a> <span class="macro">cov_mark::hit!</span>(parse_macro_def_simple); |
| <a href=#199 id=199 data-nosnippet>199</a> |
| <a href=#200 id=200 data-nosnippet>200</a> <span class="kw">let </span>rule = (|| { |
| <a href=#201 id=201 data-nosnippet>201</a> <span class="kw">let </span>lhs = MetaTemplate::parse_pattern(ctx_edition, args.iter())<span class="question-mark">?</span>; |
| <a href=#202 id=202 data-nosnippet>202</a> <span class="kw">let </span>rhs = MetaTemplate::parse_template(ctx_edition, body.iter())<span class="question-mark">?</span>; |
| <a href=#203 id=203 data-nosnippet>203</a> |
| <a href=#204 id=204 data-nosnippet>204</a> <span class="prelude-val">Ok</span>(<span class="kw">crate</span>::Rule { lhs, rhs }) |
| <a href=#205 id=205 data-nosnippet>205</a> })(); |
| <a href=#206 id=206 data-nosnippet>206</a> |
| <a href=#207 id=207 data-nosnippet>207</a> <span class="kw">match </span>rule { |
| <a href=#208 id=208 data-nosnippet>208</a> <span class="prelude-val">Ok</span>(rule) => rules.push(rule), |
| <a href=#209 id=209 data-nosnippet>209</a> <span class="prelude-val">Err</span>(e) => err = <span class="prelude-val">Some</span>(Box::new(e)), |
| <a href=#210 id=210 data-nosnippet>210</a> } |
| <a href=#211 id=211 data-nosnippet>211</a> } <span class="kw">else </span>{ |
| <a href=#212 id=212 data-nosnippet>212</a> <span class="macro">cov_mark::hit!</span>(parse_macro_def_rules); |
| <a href=#213 id=213 data-nosnippet>213</a> <span class="kw">let </span><span class="kw-2">mut </span>src = body.iter(); |
| <a href=#214 id=214 data-nosnippet>214</a> <span class="kw">while </span>!src.is_empty() { |
| <a href=#215 id=215 data-nosnippet>215</a> <span class="kw">let </span>rule = <span class="kw">match </span>Rule::parse(ctx_edition, <span class="kw-2">&mut </span>src) { |
| <a href=#216 id=216 data-nosnippet>216</a> <span class="prelude-val">Ok</span>(it) => it, |
| <a href=#217 id=217 data-nosnippet>217</a> <span class="prelude-val">Err</span>(e) => { |
| <a href=#218 id=218 data-nosnippet>218</a> err = <span class="prelude-val">Some</span>(Box::new(e)); |
| <a href=#219 id=219 data-nosnippet>219</a> <span class="kw">break</span>; |
| <a href=#220 id=220 data-nosnippet>220</a> } |
| <a href=#221 id=221 data-nosnippet>221</a> }; |
| <a href=#222 id=222 data-nosnippet>222</a> rules.push(rule); |
| <a href=#223 id=223 data-nosnippet>223</a> <span class="kw">if let </span><span class="prelude-val">Err</span>(()) = src.expect_any_char(<span class="kw-2">&</span>[<span class="string">';'</span>, <span class="string">','</span>]) { |
| <a href=#224 id=224 data-nosnippet>224</a> <span class="kw">if </span>!src.is_empty() { |
| <a href=#225 id=225 data-nosnippet>225</a> err = <span class="prelude-val">Some</span>(Box::new(ParseError::expected( |
| <a href=#226 id=226 data-nosnippet>226</a> <span class="string">"expected `;` or `,` to delimit rules"</span>, |
| <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 class="kw">break</span>; |
| <a href=#230 id=230 data-nosnippet>230</a> } |
| <a href=#231 id=231 data-nosnippet>231</a> } |
| <a href=#232 id=232 data-nosnippet>232</a> } |
| <a href=#233 id=233 data-nosnippet>233</a> |
| <a href=#234 id=234 data-nosnippet>234</a> <span class="kw">for </span>Rule { lhs, .. } <span class="kw">in </span><span class="kw-2">&</span>rules { |
| <a href=#235 id=235 data-nosnippet>235</a> <span class="kw">if let </span><span class="prelude-val">Err</span>(e) = validate(lhs) { |
| <a href=#236 id=236 data-nosnippet>236</a> err = <span class="prelude-val">Some</span>(Box::new(e)); |
| <a href=#237 id=237 data-nosnippet>237</a> <span class="kw">break</span>; |
| <a href=#238 id=238 data-nosnippet>238</a> } |
| <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> DeclarativeMacro { rules: rules.into_boxed_slice(), err } |
| <a href=#242 id=242 data-nosnippet>242</a> } |
| <a href=#243 id=243 data-nosnippet>243</a> |
| <a href=#244 id=244 data-nosnippet>244</a> <span class="kw">pub fn </span>err(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>ParseError> { |
| <a href=#245 id=245 data-nosnippet>245</a> <span class="self">self</span>.err.as_deref() |
| <a href=#246 id=246 data-nosnippet>246</a> } |
| <a href=#247 id=247 data-nosnippet>247</a> |
| <a href=#248 id=248 data-nosnippet>248</a> <span class="kw">pub fn </span>num_rules(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <a href=#249 id=249 data-nosnippet>249</a> <span class="self">self</span>.rules.len() |
| <a href=#250 id=250 data-nosnippet>250</a> } |
| <a href=#251 id=251 data-nosnippet>251</a> |
| <a href=#252 id=252 data-nosnippet>252</a> <span class="kw">pub fn </span>expand( |
| <a href=#253 id=253 data-nosnippet>253</a> <span class="kw-2">&</span><span class="self">self</span>, |
| <a href=#254 id=254 data-nosnippet>254</a> tt: <span class="kw-2">&</span>tt::TopSubtree<Span>, |
| <a href=#255 id=255 data-nosnippet>255</a> marker: <span class="kw">impl </span>Fn(<span class="kw-2">&mut </span>Span) + Copy, |
| <a href=#256 id=256 data-nosnippet>256</a> call_site: Span, |
| <a href=#257 id=257 data-nosnippet>257</a> def_site_edition: Edition, |
| <a href=#258 id=258 data-nosnippet>258</a> ) -> ExpandResult<(tt::TopSubtree<Span>, MatchedArmIndex)> { |
| <a href=#259 id=259 data-nosnippet>259</a> expander::expand_rules(<span class="kw-2">&</span><span class="self">self</span>.rules, tt, marker, call_site, def_site_edition) |
| <a href=#260 id=260 data-nosnippet>260</a> } |
| <a href=#261 id=261 data-nosnippet>261</a>} |
| <a href=#262 id=262 data-nosnippet>262</a> |
| <a href=#263 id=263 data-nosnippet>263</a><span class="kw">impl </span>Rule { |
| <a href=#264 id=264 data-nosnippet>264</a> <span class="kw">fn </span>parse( |
| <a href=#265 id=265 data-nosnippet>265</a> edition: <span class="kw">impl </span>Copy + Fn(SyntaxContext) -> Edition, |
| <a href=#266 id=266 data-nosnippet>266</a> src: <span class="kw-2">&mut </span>TtIter<<span class="lifetime">'_</span>, Span>, |
| <a href=#267 id=267 data-nosnippet>267</a> ) -> <span class="prelude-ty">Result</span><<span class="self">Self</span>, ParseError> { |
| <a href=#268 id=268 data-nosnippet>268</a> <span class="kw">let </span>(<span class="kw">_</span>, lhs) = |
| <a href=#269 id=269 data-nosnippet>269</a> src.expect_subtree().map_err(|()| ParseError::expected(<span class="string">"expected subtree"</span>))<span class="question-mark">?</span>; |
| <a href=#270 id=270 data-nosnippet>270</a> src.expect_char(<span class="string">'='</span>).map_err(|()| ParseError::expected(<span class="string">"expected `=`"</span>))<span class="question-mark">?</span>; |
| <a href=#271 id=271 data-nosnippet>271</a> src.expect_char(<span class="string">'>'</span>).map_err(|()| ParseError::expected(<span class="string">"expected `>`"</span>))<span class="question-mark">?</span>; |
| <a href=#272 id=272 data-nosnippet>272</a> <span class="kw">let </span>(<span class="kw">_</span>, rhs) = |
| <a href=#273 id=273 data-nosnippet>273</a> src.expect_subtree().map_err(|()| ParseError::expected(<span class="string">"expected subtree"</span>))<span class="question-mark">?</span>; |
| <a href=#274 id=274 data-nosnippet>274</a> |
| <a href=#275 id=275 data-nosnippet>275</a> <span class="kw">let </span>lhs = MetaTemplate::parse_pattern(edition, lhs)<span class="question-mark">?</span>; |
| <a href=#276 id=276 data-nosnippet>276</a> <span class="kw">let </span>rhs = MetaTemplate::parse_template(edition, rhs)<span class="question-mark">?</span>; |
| <a href=#277 id=277 data-nosnippet>277</a> |
| <a href=#278 id=278 data-nosnippet>278</a> <span class="prelude-val">Ok</span>(<span class="kw">crate</span>::Rule { lhs, rhs }) |
| <a href=#279 id=279 data-nosnippet>279</a> } |
| <a href=#280 id=280 data-nosnippet>280</a>} |
| <a href=#281 id=281 data-nosnippet>281</a> |
| <a href=#282 id=282 data-nosnippet>282</a><span class="kw">fn </span>validate(pattern: <span class="kw-2">&</span>MetaTemplate) -> <span class="prelude-ty">Result</span><(), ParseError> { |
| <a href=#283 id=283 data-nosnippet>283</a> <span class="kw">for </span>op <span class="kw">in </span>pattern.iter() { |
| <a href=#284 id=284 data-nosnippet>284</a> <span class="kw">match </span>op { |
| <a href=#285 id=285 data-nosnippet>285</a> Op::Subtree { tokens, .. } => validate(tokens)<span class="question-mark">?</span>, |
| <a href=#286 id=286 data-nosnippet>286</a> Op::Repeat { tokens: subtree, separator, .. } => { |
| <a href=#287 id=287 data-nosnippet>287</a> <span class="comment">// Checks that no repetition which could match an empty token |
| <a href=#288 id=288 data-nosnippet>288</a> // https://github.com/rust-lang/rust/blob/a58b1ed44f5e06976de2bdc4d7dc81c36a96934f/src/librustc_expand/mbe/macro_rules.rs#L558 |
| <a href=#289 id=289 data-nosnippet>289</a> </span><span class="kw">let </span>lsh_is_empty_seq = separator.is_none() && subtree.iter().all(|child_op| { |
| <a href=#290 id=290 data-nosnippet>290</a> <span class="kw">match </span><span class="kw-2">*</span>child_op { |
| <a href=#291 id=291 data-nosnippet>291</a> <span class="comment">// vis is optional |
| <a href=#292 id=292 data-nosnippet>292</a> </span>Op::Var { kind: <span class="prelude-val">Some</span>(kind), .. } => kind == MetaVarKind::Vis, |
| <a href=#293 id=293 data-nosnippet>293</a> Op::Repeat { |
| <a href=#294 id=294 data-nosnippet>294</a> kind: parser::RepeatKind::ZeroOrMore | parser::RepeatKind::ZeroOrOne, |
| <a href=#295 id=295 data-nosnippet>295</a> .. |
| <a href=#296 id=296 data-nosnippet>296</a> } => <span class="bool-val">true</span>, |
| <a href=#297 id=297 data-nosnippet>297</a> <span class="kw">_ </span>=> <span class="bool-val">false</span>, |
| <a href=#298 id=298 data-nosnippet>298</a> } |
| <a href=#299 id=299 data-nosnippet>299</a> }); |
| <a href=#300 id=300 data-nosnippet>300</a> <span class="kw">if </span>lsh_is_empty_seq { |
| <a href=#301 id=301 data-nosnippet>301</a> <span class="kw">return </span><span class="prelude-val">Err</span>(ParseError::RepetitionEmptyTokenTree); |
| <a href=#302 id=302 data-nosnippet>302</a> } |
| <a href=#303 id=303 data-nosnippet>303</a> validate(subtree)<span class="question-mark">? |
| <a href=#304 id=304 data-nosnippet>304</a> </span>} |
| <a href=#305 id=305 data-nosnippet>305</a> <span class="kw">_ </span>=> (), |
| <a href=#306 id=306 data-nosnippet>306</a> } |
| <a href=#307 id=307 data-nosnippet>307</a> } |
| <a href=#308 id=308 data-nosnippet>308</a> <span class="prelude-val">Ok</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="kw">pub type </span>ExpandResult<T> = ValueResult<T, ExpandError>; |
| <a href=#312 id=312 data-nosnippet>312</a> |
| <a href=#313 id=313 data-nosnippet>313</a><span class="attr">#[derive(Debug, Clone, Eq, PartialEq)] |
| <a href=#314 id=314 data-nosnippet>314</a></span><span class="kw">pub struct </span>ValueResult<T, E> { |
| <a href=#315 id=315 data-nosnippet>315</a> <span class="kw">pub </span>value: T, |
| <a href=#316 id=316 data-nosnippet>316</a> <span class="kw">pub </span>err: <span class="prelude-ty">Option</span><E>, |
| <a href=#317 id=317 data-nosnippet>317</a>} |
| <a href=#318 id=318 data-nosnippet>318</a> |
| <a href=#319 id=319 data-nosnippet>319</a><span class="kw">impl</span><T: Default, E> Default <span class="kw">for </span>ValueResult<T, E> { |
| <a href=#320 id=320 data-nosnippet>320</a> <span class="kw">fn </span>default() -> <span class="self">Self </span>{ |
| <a href=#321 id=321 data-nosnippet>321</a> <span class="self">Self </span>{ value: Default::default(), err: Default::default() } |
| <a href=#322 id=322 data-nosnippet>322</a> } |
| <a href=#323 id=323 data-nosnippet>323</a>} |
| <a href=#324 id=324 data-nosnippet>324</a> |
| <a href=#325 id=325 data-nosnippet>325</a><span class="kw">impl</span><T, E> ValueResult<T, E> { |
| <a href=#326 id=326 data-nosnippet>326</a> <span class="kw">pub fn </span>new(value: T, err: E) -> <span class="self">Self </span>{ |
| <a href=#327 id=327 data-nosnippet>327</a> <span class="self">Self </span>{ value, err: <span class="prelude-val">Some</span>(err) } |
| <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="kw">pub fn </span>ok(value: T) -> <span class="self">Self </span>{ |
| <a href=#331 id=331 data-nosnippet>331</a> <span class="self">Self </span>{ value, err: <span class="prelude-val">None </span>} |
| <a href=#332 id=332 data-nosnippet>332</a> } |
| <a href=#333 id=333 data-nosnippet>333</a> |
| <a href=#334 id=334 data-nosnippet>334</a> <span class="kw">pub fn </span>only_err(err: E) -> <span class="self">Self |
| <a href=#335 id=335 data-nosnippet>335</a> </span><span class="kw">where |
| <a href=#336 id=336 data-nosnippet>336</a> </span>T: Default, |
| <a href=#337 id=337 data-nosnippet>337</a> { |
| <a href=#338 id=338 data-nosnippet>338</a> <span class="self">Self </span>{ value: Default::default(), err: <span class="prelude-val">Some</span>(err) } |
| <a href=#339 id=339 data-nosnippet>339</a> } |
| <a href=#340 id=340 data-nosnippet>340</a> |
| <a href=#341 id=341 data-nosnippet>341</a> <span class="kw">pub fn </span>zip_val<U>(<span class="self">self</span>, other: U) -> ValueResult<(T, U), E> { |
| <a href=#342 id=342 data-nosnippet>342</a> ValueResult { value: (<span class="self">self</span>.value, other), err: <span class="self">self</span>.err } |
| <a href=#343 id=343 data-nosnippet>343</a> } |
| <a href=#344 id=344 data-nosnippet>344</a> |
| <a href=#345 id=345 data-nosnippet>345</a> <span class="kw">pub fn </span>map<U>(<span class="self">self</span>, f: <span class="kw">impl </span>FnOnce(T) -> U) -> ValueResult<U, E> { |
| <a href=#346 id=346 data-nosnippet>346</a> ValueResult { value: f(<span class="self">self</span>.value), err: <span class="self">self</span>.err } |
| <a href=#347 id=347 data-nosnippet>347</a> } |
| <a href=#348 id=348 data-nosnippet>348</a> |
| <a href=#349 id=349 data-nosnippet>349</a> <span class="kw">pub fn </span>map_err<E2>(<span class="self">self</span>, f: <span class="kw">impl </span>FnOnce(E) -> E2) -> ValueResult<T, E2> { |
| <a href=#350 id=350 data-nosnippet>350</a> ValueResult { value: <span class="self">self</span>.value, err: <span class="self">self</span>.err.map(f) } |
| <a href=#351 id=351 data-nosnippet>351</a> } |
| <a href=#352 id=352 data-nosnippet>352</a> |
| <a href=#353 id=353 data-nosnippet>353</a> <span class="kw">pub fn </span>result(<span class="self">self</span>) -> <span class="prelude-ty">Result</span><T, E> { |
| <a href=#354 id=354 data-nosnippet>354</a> <span class="self">self</span>.err.map_or(<span class="prelude-val">Ok</span>(<span class="self">self</span>.value), <span class="prelude-val">Err</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> |
| <a href=#358 id=358 data-nosnippet>358</a><span class="kw">impl</span><T: Default, E> From<<span class="prelude-ty">Result</span><T, E>> <span class="kw">for </span>ValueResult<T, E> { |
| <a href=#359 id=359 data-nosnippet>359</a> <span class="kw">fn </span>from(result: <span class="prelude-ty">Result</span><T, E>) -> <span class="self">Self </span>{ |
| <a href=#360 id=360 data-nosnippet>360</a> result.map_or_else(<span class="self">Self</span>::only_err, <span class="self">Self</span>::ok) |
| <a href=#361 id=361 data-nosnippet>361</a> } |
| <a href=#362 id=362 data-nosnippet>362</a>} |
| <a href=#363 id=363 data-nosnippet>363</a> |
| <a href=#364 id=364 data-nosnippet>364</a><span class="kw">pub fn </span>expect_fragment<<span class="lifetime">'t</span>>( |
| <a href=#365 id=365 data-nosnippet>365</a> tt_iter: <span class="kw-2">&mut </span>TtIter<<span class="lifetime">'t</span>, Span>, |
| <a href=#366 id=366 data-nosnippet>366</a> entry_point: ::parser::PrefixEntryPoint, |
| <a href=#367 id=367 data-nosnippet>367</a> edition: ::parser::Edition, |
| <a href=#368 id=368 data-nosnippet>368</a> delim_span: DelimSpan<Span>, |
| <a href=#369 id=369 data-nosnippet>369</a>) -> ExpandResult<tt::TokenTreesView<<span class="lifetime">'t</span>, Span>> { |
| <a href=#370 id=370 data-nosnippet>370</a> <span class="kw">use </span>::parser; |
| <a href=#371 id=371 data-nosnippet>371</a> <span class="kw">let </span>buffer = tt_iter.remaining(); |
| <a href=#372 id=372 data-nosnippet>372</a> <span class="comment">// FIXME: Pass the correct edition per token. Due to the split between mbe and hir-expand it's complicated. |
| <a href=#373 id=373 data-nosnippet>373</a> </span><span class="kw">let </span>parser_input = to_parser_input(buffer, <span class="kw-2">&mut </span>|_ctx| edition); |
| <a href=#374 id=374 data-nosnippet>374</a> <span class="kw">let </span>tree_traversal = entry_point.parse(<span class="kw-2">&</span>parser_input, edition); |
| <a href=#375 id=375 data-nosnippet>375</a> <span class="kw">let </span><span class="kw-2">mut </span>cursor = buffer.cursor(); |
| <a href=#376 id=376 data-nosnippet>376</a> <span class="kw">let </span><span class="kw-2">mut </span>error = <span class="bool-val">false</span>; |
| <a href=#377 id=377 data-nosnippet>377</a> <span class="kw">for </span>step <span class="kw">in </span>tree_traversal.iter() { |
| <a href=#378 id=378 data-nosnippet>378</a> <span class="kw">match </span>step { |
| <a href=#379 id=379 data-nosnippet>379</a> parser::Step::Token { kind, <span class="kw-2">mut </span>n_input_tokens } => { |
| <a href=#380 id=380 data-nosnippet>380</a> <span class="kw">if </span>kind == ::parser::SyntaxKind::LIFETIME_IDENT { |
| <a href=#381 id=381 data-nosnippet>381</a> n_input_tokens = <span class="number">2</span>; |
| <a href=#382 id=382 data-nosnippet>382</a> } |
| <a href=#383 id=383 data-nosnippet>383</a> <span class="kw">for _ in </span><span class="number">0</span>..n_input_tokens { |
| <a href=#384 id=384 data-nosnippet>384</a> cursor.bump_or_end(); |
| <a href=#385 id=385 data-nosnippet>385</a> } |
| <a href=#386 id=386 data-nosnippet>386</a> } |
| <a href=#387 id=387 data-nosnippet>387</a> parser::Step::FloatSplit { .. } => { |
| <a href=#388 id=388 data-nosnippet>388</a> <span class="comment">// FIXME: We need to split the tree properly here, but mutating the token trees |
| <a href=#389 id=389 data-nosnippet>389</a> // in the buffer is somewhat tricky to pull off. |
| <a href=#390 id=390 data-nosnippet>390</a> </span>cursor.bump_or_end(); |
| <a href=#391 id=391 data-nosnippet>391</a> } |
| <a href=#392 id=392 data-nosnippet>392</a> parser::Step::Enter { .. } | parser::Step::Exit => (), |
| <a href=#393 id=393 data-nosnippet>393</a> parser::Step::Error { .. } => error = <span class="bool-val">true</span>, |
| <a href=#394 id=394 data-nosnippet>394</a> } |
| <a href=#395 id=395 data-nosnippet>395</a> } |
| <a href=#396 id=396 data-nosnippet>396</a> |
| <a href=#397 id=397 data-nosnippet>397</a> <span class="kw">let </span>err = <span class="kw">if </span>error || !cursor.is_root() { |
| <a href=#398 id=398 data-nosnippet>398</a> <span class="prelude-val">Some</span>(ExpandError::binding_error( |
| <a href=#399 id=399 data-nosnippet>399</a> buffer.cursor().token_tree().map_or(delim_span.close, |tt| tt.first_span()), |
| <a href=#400 id=400 data-nosnippet>400</a> <span class="macro">format!</span>(<span class="string">"expected {entry_point:?}"</span>), |
| <a href=#401 id=401 data-nosnippet>401</a> )) |
| <a href=#402 id=402 data-nosnippet>402</a> } <span class="kw">else </span>{ |
| <a href=#403 id=403 data-nosnippet>403</a> <span class="prelude-val">None |
| <a href=#404 id=404 data-nosnippet>404</a> </span>}; |
| <a href=#405 id=405 data-nosnippet>405</a> |
| <a href=#406 id=406 data-nosnippet>406</a> <span class="kw">while </span>!cursor.is_root() { |
| <a href=#407 id=407 data-nosnippet>407</a> cursor.bump_or_end(); |
| <a href=#408 id=408 data-nosnippet>408</a> } |
| <a href=#409 id=409 data-nosnippet>409</a> |
| <a href=#410 id=410 data-nosnippet>410</a> <span class="kw">let </span>res = cursor.crossed(); |
| <a href=#411 id=411 data-nosnippet>411</a> tt_iter.flat_advance(res.len()); |
| <a href=#412 id=412 data-nosnippet>412</a> |
| <a href=#413 id=413 data-nosnippet>413</a> ExpandResult { value: res, err } |
| <a href=#414 id=414 data-nosnippet>414</a>}</code></pre></div></section></main></body></html> |
