| <!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/ast/prec.rs`."><title>prec.rs - source</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2"href="../../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../../static.files/rustdoc-ca0dd0c4.css"><meta name="rustdoc-vars" data-root-path="../../../" data-static-root-path="../../../static.files/" data-current-crate="syntax" data-themes="" data-resource-suffix="" data-rustdoc-version="1.93.0 (254b59607 2026-01-19)" data-channel="1.93.0" data-search-js="search-9e2438ea.js" data-stringdex-js="stringdex-a3946164.js" data-settings-js="settings-c38705f0.js" ><script src="../../../static.files/storage-e2aeef58.js"></script><script defer src="../../../static.files/src-script-813739b1.js"></script><script defer src="../../../src-files.js"></script><script defer src="../../../static.files/main-a410ff4d.js"></script><noscript><link rel="stylesheet" href="../../../static.files/noscript-263c88ec.css"></noscript><link rel="alternate icon" type="image/png" href="../../../static.files/favicon-32x32-eab170b8.png"><link rel="icon" type="image/svg+xml" href="../../../static.files/favicon-044be391.svg"></head><body class="rustdoc src"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">syntax/ast/</div>prec.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">//! Precedence representation. |
| <a href=#2 id=2 data-nosnippet>2</a> |
| <a href=#3 id=3 data-nosnippet>3</a></span><span class="kw">use </span>stdx::always; |
| <a href=#4 id=4 data-nosnippet>4</a> |
| <a href=#5 id=5 data-nosnippet>5</a><span class="kw">use crate</span>::{ |
| <a href=#6 id=6 data-nosnippet>6</a> AstNode, Direction, SyntaxNode, T, |
| <a href=#7 id=7 data-nosnippet>7</a> algo::skip_trivia_token, |
| <a href=#8 id=8 data-nosnippet>8</a> ast::{<span class="self">self</span>, BinaryOp, Expr, HasArgList, RangeItem}, |
| <a href=#9 id=9 data-nosnippet>9</a> match_ast, |
| <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="attr">#[derive(Debug, Clone, Copy, PartialEq, PartialOrd)] |
| <a href=#13 id=13 data-nosnippet>13</a></span><span class="kw">pub enum </span>ExprPrecedence { |
| <a href=#14 id=14 data-nosnippet>14</a> <span class="comment">// return, break, continue, yield, yeet, become (with or without value) |
| <a href=#15 id=15 data-nosnippet>15</a> </span>Jump, |
| <a href=#16 id=16 data-nosnippet>16</a> <span class="comment">// = += -= *= /= %= &= |= ^= <<= >>= |
| <a href=#17 id=17 data-nosnippet>17</a> </span>Assign, |
| <a href=#18 id=18 data-nosnippet>18</a> <span class="comment">// .. ..= |
| <a href=#19 id=19 data-nosnippet>19</a> </span>Range, |
| <a href=#20 id=20 data-nosnippet>20</a> <span class="comment">// || |
| <a href=#21 id=21 data-nosnippet>21</a> </span>LOr, |
| <a href=#22 id=22 data-nosnippet>22</a> <span class="comment">// && |
| <a href=#23 id=23 data-nosnippet>23</a> </span>LAnd, |
| <a href=#24 id=24 data-nosnippet>24</a> <span class="comment">// == != < > <= >= |
| <a href=#25 id=25 data-nosnippet>25</a> </span>Compare, |
| <a href=#26 id=26 data-nosnippet>26</a> <span class="comment">// | |
| <a href=#27 id=27 data-nosnippet>27</a> </span>BitOr, |
| <a href=#28 id=28 data-nosnippet>28</a> <span class="comment">// ^ |
| <a href=#29 id=29 data-nosnippet>29</a> </span>BitXor, |
| <a href=#30 id=30 data-nosnippet>30</a> <span class="comment">// & |
| <a href=#31 id=31 data-nosnippet>31</a> </span>BitAnd, |
| <a href=#32 id=32 data-nosnippet>32</a> <span class="comment">// << >> |
| <a href=#33 id=33 data-nosnippet>33</a> </span>Shift, |
| <a href=#34 id=34 data-nosnippet>34</a> <span class="comment">// + - |
| <a href=#35 id=35 data-nosnippet>35</a> </span>Sum, |
| <a href=#36 id=36 data-nosnippet>36</a> <span class="comment">// * / % |
| <a href=#37 id=37 data-nosnippet>37</a> </span>Product, |
| <a href=#38 id=38 data-nosnippet>38</a> <span class="comment">// as |
| <a href=#39 id=39 data-nosnippet>39</a> </span>Cast, |
| <a href=#40 id=40 data-nosnippet>40</a> <span class="comment">// unary - * ! & &mut |
| <a href=#41 id=41 data-nosnippet>41</a> </span>Prefix, |
| <a href=#42 id=42 data-nosnippet>42</a> <span class="comment">// function calls, array indexing, field expressions, method calls |
| <a href=#43 id=43 data-nosnippet>43</a> </span>Postfix, |
| <a href=#44 id=44 data-nosnippet>44</a> <span class="comment">// paths, loops, |
| <a href=#45 id=45 data-nosnippet>45</a> </span>Unambiguous, |
| <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="kw">impl </span>ExprPrecedence { |
| <a href=#49 id=49 data-nosnippet>49</a> <span class="kw">pub fn </span>needs_parentheses_in(<span class="self">self</span>, other: ExprPrecedence) -> bool { |
| <a href=#50 id=50 data-nosnippet>50</a> <span class="kw">match </span>other { |
| <a href=#51 id=51 data-nosnippet>51</a> ExprPrecedence::Unambiguous => <span class="bool-val">false</span>, |
| <a href=#52 id=52 data-nosnippet>52</a> <span class="comment">// postfix ops have higher precedence than any other operator, so we need to wrap |
| <a href=#53 id=53 data-nosnippet>53</a> // any inner expression that is below |
| <a href=#54 id=54 data-nosnippet>54</a> </span>ExprPrecedence::Postfix => <span class="self">self </span>< ExprPrecedence::Postfix, |
| <a href=#55 id=55 data-nosnippet>55</a> <span class="comment">// We need to wrap all binary like things, thats everything below prefix except for |
| <a href=#56 id=56 data-nosnippet>56</a> // jumps (as those are prefix operations as well) |
| <a href=#57 id=57 data-nosnippet>57</a> </span>ExprPrecedence::Prefix => ExprPrecedence::Jump < <span class="self">self </span>&& <span class="self">self </span>< ExprPrecedence::Prefix, |
| <a href=#58 id=58 data-nosnippet>58</a> parent => <span class="self">self </span><= parent, |
| <a href=#59 id=59 data-nosnippet>59</a> } |
| <a href=#60 id=60 data-nosnippet>60</a> } |
| <a href=#61 id=61 data-nosnippet>61</a>} |
| <a href=#62 id=62 data-nosnippet>62</a> |
| <a href=#63 id=63 data-nosnippet>63</a><span class="attr">#[derive(PartialEq, Debug)] |
| <a href=#64 id=64 data-nosnippet>64</a></span><span class="kw">pub enum </span>Fixity { |
| <a href=#65 id=65 data-nosnippet>65</a> <span class="doccomment">/// The operator is left-associative |
| <a href=#66 id=66 data-nosnippet>66</a> </span>Left, |
| <a href=#67 id=67 data-nosnippet>67</a> <span class="doccomment">/// The operator is right-associative |
| <a href=#68 id=68 data-nosnippet>68</a> </span>Right, |
| <a href=#69 id=69 data-nosnippet>69</a> <span class="doccomment">/// The operator is not associative |
| <a href=#70 id=70 data-nosnippet>70</a> </span><span class="prelude-val">None</span>, |
| <a href=#71 id=71 data-nosnippet>71</a>} |
| <a href=#72 id=72 data-nosnippet>72</a> |
| <a href=#73 id=73 data-nosnippet>73</a><span class="kw">pub fn </span>precedence(expr: <span class="kw-2">&</span>ast::Expr) -> ExprPrecedence { |
| <a href=#74 id=74 data-nosnippet>74</a> <span class="kw">match </span>expr { |
| <a href=#75 id=75 data-nosnippet>75</a> Expr::ClosureExpr(closure) => <span class="kw">match </span>closure.ret_type() { |
| <a href=#76 id=76 data-nosnippet>76</a> <span class="prelude-val">None </span>=> ExprPrecedence::Jump, |
| <a href=#77 id=77 data-nosnippet>77</a> <span class="prelude-val">Some</span>(<span class="kw">_</span>) => ExprPrecedence::Unambiguous, |
| <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> Expr::BreakExpr(<span class="kw">_</span>) |
| <a href=#81 id=81 data-nosnippet>81</a> | Expr::BecomeExpr(<span class="kw">_</span>) |
| <a href=#82 id=82 data-nosnippet>82</a> | Expr::ReturnExpr(<span class="kw">_</span>) |
| <a href=#83 id=83 data-nosnippet>83</a> | Expr::YeetExpr(<span class="kw">_</span>) |
| <a href=#84 id=84 data-nosnippet>84</a> | Expr::YieldExpr(<span class="kw">_</span>) |
| <a href=#85 id=85 data-nosnippet>85</a> | Expr::ContinueExpr(<span class="kw">_</span>) => ExprPrecedence::Jump, |
| <a href=#86 id=86 data-nosnippet>86</a> |
| <a href=#87 id=87 data-nosnippet>87</a> Expr::RangeExpr(..) => ExprPrecedence::Range, |
| <a href=#88 id=88 data-nosnippet>88</a> |
| <a href=#89 id=89 data-nosnippet>89</a> Expr::BinExpr(bin_expr) => <span class="kw">match </span>bin_expr.op_kind() { |
| <a href=#90 id=90 data-nosnippet>90</a> <span class="prelude-val">Some</span>(it) => <span class="kw">match </span>it { |
| <a href=#91 id=91 data-nosnippet>91</a> BinaryOp::LogicOp(logic_op) => <span class="kw">match </span>logic_op { |
| <a href=#92 id=92 data-nosnippet>92</a> ast::LogicOp::And => ExprPrecedence::LAnd, |
| <a href=#93 id=93 data-nosnippet>93</a> ast::LogicOp::Or => ExprPrecedence::LOr, |
| <a href=#94 id=94 data-nosnippet>94</a> }, |
| <a href=#95 id=95 data-nosnippet>95</a> BinaryOp::ArithOp(arith_op) => <span class="kw">match </span>arith_op { |
| <a href=#96 id=96 data-nosnippet>96</a> ast::ArithOp::Add | ast::ArithOp::Sub => ExprPrecedence::Sum, |
| <a href=#97 id=97 data-nosnippet>97</a> ast::ArithOp::Div | ast::ArithOp::Rem | ast::ArithOp::Mul => { |
| <a href=#98 id=98 data-nosnippet>98</a> ExprPrecedence::Product |
| <a href=#99 id=99 data-nosnippet>99</a> } |
| <a href=#100 id=100 data-nosnippet>100</a> ast::ArithOp::Shl | ast::ArithOp::Shr => ExprPrecedence::Shift, |
| <a href=#101 id=101 data-nosnippet>101</a> ast::ArithOp::BitXor => ExprPrecedence::BitXor, |
| <a href=#102 id=102 data-nosnippet>102</a> ast::ArithOp::BitOr => ExprPrecedence::BitOr, |
| <a href=#103 id=103 data-nosnippet>103</a> ast::ArithOp::BitAnd => ExprPrecedence::BitAnd, |
| <a href=#104 id=104 data-nosnippet>104</a> }, |
| <a href=#105 id=105 data-nosnippet>105</a> BinaryOp::CmpOp(<span class="kw">_</span>) => ExprPrecedence::Compare, |
| <a href=#106 id=106 data-nosnippet>106</a> BinaryOp::Assignment { .. } => ExprPrecedence::Assign, |
| <a href=#107 id=107 data-nosnippet>107</a> }, |
| <a href=#108 id=108 data-nosnippet>108</a> <span class="prelude-val">None </span>=> ExprPrecedence::Unambiguous, |
| <a href=#109 id=109 data-nosnippet>109</a> }, |
| <a href=#110 id=110 data-nosnippet>110</a> Expr::CastExpr(<span class="kw">_</span>) => ExprPrecedence::Cast, |
| <a href=#111 id=111 data-nosnippet>111</a> |
| <a href=#112 id=112 data-nosnippet>112</a> Expr::LetExpr(<span class="kw">_</span>) | Expr::PrefixExpr(<span class="kw">_</span>) | Expr::RefExpr(<span class="kw">_</span>) => ExprPrecedence::Prefix, |
| <a href=#113 id=113 data-nosnippet>113</a> |
| <a href=#114 id=114 data-nosnippet>114</a> Expr::AwaitExpr(<span class="kw">_</span>) |
| <a href=#115 id=115 data-nosnippet>115</a> | Expr::CallExpr(<span class="kw">_</span>) |
| <a href=#116 id=116 data-nosnippet>116</a> | Expr::FieldExpr(<span class="kw">_</span>) |
| <a href=#117 id=117 data-nosnippet>117</a> | Expr::IndexExpr(<span class="kw">_</span>) |
| <a href=#118 id=118 data-nosnippet>118</a> | Expr::MethodCallExpr(<span class="kw">_</span>) |
| <a href=#119 id=119 data-nosnippet>119</a> | Expr::TryExpr(<span class="kw">_</span>) => ExprPrecedence::Postfix, |
| <a href=#120 id=120 data-nosnippet>120</a> |
| <a href=#121 id=121 data-nosnippet>121</a> Expr::ArrayExpr(<span class="kw">_</span>) |
| <a href=#122 id=122 data-nosnippet>122</a> | Expr::AsmExpr(<span class="kw">_</span>) |
| <a href=#123 id=123 data-nosnippet>123</a> | Expr::BlockExpr(<span class="kw">_</span>) |
| <a href=#124 id=124 data-nosnippet>124</a> | Expr::ForExpr(<span class="kw">_</span>) |
| <a href=#125 id=125 data-nosnippet>125</a> | Expr::FormatArgsExpr(<span class="kw">_</span>) |
| <a href=#126 id=126 data-nosnippet>126</a> | Expr::IfExpr(<span class="kw">_</span>) |
| <a href=#127 id=127 data-nosnippet>127</a> | Expr::Literal(<span class="kw">_</span>) |
| <a href=#128 id=128 data-nosnippet>128</a> | Expr::LoopExpr(<span class="kw">_</span>) |
| <a href=#129 id=129 data-nosnippet>129</a> | Expr::MacroExpr(<span class="kw">_</span>) |
| <a href=#130 id=130 data-nosnippet>130</a> | Expr::MatchExpr(<span class="kw">_</span>) |
| <a href=#131 id=131 data-nosnippet>131</a> | Expr::OffsetOfExpr(<span class="kw">_</span>) |
| <a href=#132 id=132 data-nosnippet>132</a> | Expr::ParenExpr(<span class="kw">_</span>) |
| <a href=#133 id=133 data-nosnippet>133</a> | Expr::PathExpr(<span class="kw">_</span>) |
| <a href=#134 id=134 data-nosnippet>134</a> | Expr::RecordExpr(<span class="kw">_</span>) |
| <a href=#135 id=135 data-nosnippet>135</a> | Expr::TupleExpr(<span class="kw">_</span>) |
| <a href=#136 id=136 data-nosnippet>136</a> | Expr::UnderscoreExpr(<span class="kw">_</span>) |
| <a href=#137 id=137 data-nosnippet>137</a> | Expr::WhileExpr(<span class="kw">_</span>) => ExprPrecedence::Unambiguous, |
| <a href=#138 id=138 data-nosnippet>138</a> } |
| <a href=#139 id=139 data-nosnippet>139</a>} |
| <a href=#140 id=140 data-nosnippet>140</a> |
| <a href=#141 id=141 data-nosnippet>141</a><span class="kw">fn </span>check_ancestry(ancestor: <span class="kw-2">&</span>SyntaxNode, descendent: <span class="kw-2">&</span>SyntaxNode) -> bool { |
| <a href=#142 id=142 data-nosnippet>142</a> <span class="kw">let </span>bail = || <span class="macro">always!</span>(<span class="bool-val">false</span>, <span class="string">"{} is not an ancestor of {}"</span>, ancestor, descendent); |
| <a href=#143 id=143 data-nosnippet>143</a> |
| <a href=#144 id=144 data-nosnippet>144</a> <span class="kw">if </span>!ancestor.text_range().contains_range(descendent.text_range()) { |
| <a href=#145 id=145 data-nosnippet>145</a> <span class="kw">return </span>bail(); |
| <a href=#146 id=146 data-nosnippet>146</a> } |
| <a href=#147 id=147 data-nosnippet>147</a> |
| <a href=#148 id=148 data-nosnippet>148</a> <span class="kw">for </span>anc <span class="kw">in </span>descendent.ancestors() { |
| <a href=#149 id=149 data-nosnippet>149</a> <span class="kw">if </span>anc == <span class="kw-2">*</span>ancestor { |
| <a href=#150 id=150 data-nosnippet>150</a> <span class="kw">return </span><span class="bool-val">true</span>; |
| <a href=#151 id=151 data-nosnippet>151</a> } |
| <a href=#152 id=152 data-nosnippet>152</a> } |
| <a href=#153 id=153 data-nosnippet>153</a> |
| <a href=#154 id=154 data-nosnippet>154</a> bail() |
| <a href=#155 id=155 data-nosnippet>155</a>} |
| <a href=#156 id=156 data-nosnippet>156</a> |
| <a href=#157 id=157 data-nosnippet>157</a><span class="kw">fn </span>next_token_of(node: <span class="kw-2">&</span>SyntaxNode) -> <span class="prelude-ty">Option</span><ast::SyntaxToken> { |
| <a href=#158 id=158 data-nosnippet>158</a> <span class="kw">let </span>last = node.last_token()<span class="question-mark">?</span>; |
| <a href=#159 id=159 data-nosnippet>159</a> skip_trivia_token(last.next_token()<span class="question-mark">?</span>, Direction::Next) |
| <a href=#160 id=160 data-nosnippet>160</a>} |
| <a href=#161 id=161 data-nosnippet>161</a> |
| <a href=#162 id=162 data-nosnippet>162</a><span class="kw">impl </span>Expr { |
| <a href=#163 id=163 data-nosnippet>163</a> <span class="kw">pub fn </span>precedence(<span class="kw-2">&</span><span class="self">self</span>) -> ExprPrecedence { |
| <a href=#164 id=164 data-nosnippet>164</a> precedence(<span class="self">self</span>) |
| <a href=#165 id=165 data-nosnippet>165</a> } |
| <a href=#166 id=166 data-nosnippet>166</a> |
| <a href=#167 id=167 data-nosnippet>167</a> <span class="comment">// Implementation is based on |
| <a href=#168 id=168 data-nosnippet>168</a> // - https://doc.rust-lang.org/reference/expressions.html#expression-precedence |
| <a href=#169 id=169 data-nosnippet>169</a> // - https://matklad.github.io/2020/04/13/simple-but-powerful-pratt-parsing.html |
| <a href=#170 id=170 data-nosnippet>170</a> // - rustc source, including, but not limited to |
| <a href=#171 id=171 data-nosnippet>171</a> // - https://github.com/rust-lang/rust/blob/b6852428a8ea9728369b64b9964cad8e258403d3/compiler/rustc_ast/src/util/parser.rs#L296 |
| <a href=#172 id=172 data-nosnippet>172</a> |
| <a href=#173 id=173 data-nosnippet>173</a> </span><span class="doccomment">/// Returns `true` if `self` would need to be wrapped in parentheses given that its parent is `parent`. |
| <a href=#174 id=174 data-nosnippet>174</a> </span><span class="kw">pub fn </span>needs_parens_in(<span class="kw-2">&</span><span class="self">self</span>, parent: <span class="kw-2">&</span>SyntaxNode) -> bool { |
| <a href=#175 id=175 data-nosnippet>175</a> <span class="self">self</span>.needs_parens_in_place_of(parent, <span class="self">self</span>.syntax()) |
| <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="doccomment">/// Returns `true` if `self` would need to be wrapped in parentheses if it replaces `place_of` |
| <a href=#179 id=179 data-nosnippet>179</a> /// given that `place_of`'s parent is `parent`. |
| <a href=#180 id=180 data-nosnippet>180</a> </span><span class="kw">pub fn </span>needs_parens_in_place_of(<span class="kw-2">&</span><span class="self">self</span>, parent: <span class="kw-2">&</span>SyntaxNode, place_of: <span class="kw-2">&</span>SyntaxNode) -> bool { |
| <a href=#181 id=181 data-nosnippet>181</a> <span class="kw">if </span>!check_ancestry(parent, place_of) { |
| <a href=#182 id=182 data-nosnippet>182</a> <span class="kw">return </span><span class="bool-val">false</span>; |
| <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> <span class="macro">match_ast!</span> { |
| <a href=#186 id=186 data-nosnippet>186</a> <span class="kw">match </span>parent { |
| <a href=#187 id=187 data-nosnippet>187</a> ast::Expr(e) => <span class="self">self</span>.needs_parens_in_expr(<span class="kw-2">&</span>e, place_of), |
| <a href=#188 id=188 data-nosnippet>188</a> ast::Stmt(e) => <span class="self">self</span>.needs_parens_in_stmt(<span class="prelude-val">Some</span>(<span class="kw-2">&</span>e)), |
| <a href=#189 id=189 data-nosnippet>189</a> ast::StmtList(<span class="kw">_</span>) => <span class="self">self</span>.needs_parens_in_stmt(<span class="prelude-val">None</span>), |
| <a href=#190 id=190 data-nosnippet>190</a> ast::ArgList(<span class="kw">_</span>) => <span class="bool-val">false</span>, |
| <a href=#191 id=191 data-nosnippet>191</a> ast::MatchArm(<span class="kw">_</span>) => <span class="bool-val">false</span>, |
| <a href=#192 id=192 data-nosnippet>192</a> <span class="kw">_ </span>=> <span class="bool-val">false</span>, |
| <a href=#193 id=193 data-nosnippet>193</a> } |
| <a href=#194 id=194 data-nosnippet>194</a> } |
| <a href=#195 id=195 data-nosnippet>195</a> } |
| <a href=#196 id=196 data-nosnippet>196</a> |
| <a href=#197 id=197 data-nosnippet>197</a> <span class="kw">fn </span>needs_parens_in_expr(<span class="kw-2">&</span><span class="self">self</span>, parent: <span class="kw-2">&</span>Expr, place_of: <span class="kw-2">&</span>SyntaxNode) -> bool { |
| <a href=#198 id=198 data-nosnippet>198</a> <span class="comment">// Parentheses are necessary when calling a function-like pointer that is a member of a struct or union |
| <a href=#199 id=199 data-nosnippet>199</a> // (e.g. `(a.f)()`). |
| <a href=#200 id=200 data-nosnippet>200</a> </span><span class="kw">let </span>is_parent_call_expr = <span class="macro">matches!</span>(parent, ast::Expr::CallExpr(<span class="kw">_</span>)); |
| <a href=#201 id=201 data-nosnippet>201</a> <span class="kw">let </span>is_field_expr = <span class="macro">matches!</span>(<span class="self">self</span>, ast::Expr::FieldExpr(<span class="kw">_</span>)); |
| <a href=#202 id=202 data-nosnippet>202</a> <span class="kw">if </span>is_parent_call_expr && is_field_expr { |
| <a href=#203 id=203 data-nosnippet>203</a> <span class="kw">return </span><span class="bool-val">true</span>; |
| <a href=#204 id=204 data-nosnippet>204</a> } |
| <a href=#205 id=205 data-nosnippet>205</a> <span class="kw">let </span>place_of_parent = |
| <a href=#206 id=206 data-nosnippet>206</a> || place_of.ancestors().find(|it| it.parent().is_none_or(|p| <span class="kw-2">&</span>p == parent.syntax())); |
| <a href=#207 id=207 data-nosnippet>207</a> |
| <a href=#208 id=208 data-nosnippet>208</a> <span class="comment">// Special-case block weirdness |
| <a href=#209 id=209 data-nosnippet>209</a> </span><span class="kw">if </span>parent.child_is_followed_by_a_block() { |
| <a href=#210 id=210 data-nosnippet>210</a> <span class="kw">use </span>Expr::<span class="kw-2">*</span>; |
| <a href=#211 id=211 data-nosnippet>211</a> <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#212 id=212 data-nosnippet>212</a> <span class="comment">// Cases like `if return {}` (need parens or else `{}` is returned, instead of being `if`'s body) |
| <a href=#213 id=213 data-nosnippet>213</a> </span>ReturnExpr(e) <span class="kw">if </span>e.expr().is_none() => <span class="kw">return </span><span class="bool-val">true</span>, |
| <a href=#214 id=214 data-nosnippet>214</a> BreakExpr(e) <span class="kw">if </span>e.expr().is_none() => <span class="kw">return </span><span class="bool-val">true</span>, |
| <a href=#215 id=215 data-nosnippet>215</a> YieldExpr(e) <span class="kw">if </span>e.expr().is_none() => <span class="kw">return </span><span class="bool-val">true</span>, |
| <a href=#216 id=216 data-nosnippet>216</a> |
| <a href=#217 id=217 data-nosnippet>217</a> <span class="comment">// Same but with `..{}` |
| <a href=#218 id=218 data-nosnippet>218</a> </span>RangeExpr(e) <span class="kw">if </span><span class="macro">matches!</span>(e.end(), <span class="prelude-val">Some</span>(BlockExpr(..))) => <span class="kw">return </span><span class="bool-val">true</span>, |
| <a href=#219 id=219 data-nosnippet>219</a> |
| <a href=#220 id=220 data-nosnippet>220</a> <span class="comment">// Similarly with struct literals, e.g. `if S{} == 1 {}` |
| <a href=#221 id=221 data-nosnippet>221</a> </span><span class="kw">_ if </span><span class="self">self</span>.contains_exterior_struct_lit() => <span class="kw">return </span><span class="bool-val">true</span>, |
| <a href=#222 id=222 data-nosnippet>222</a> <span class="kw">_ </span>=> {} |
| <a href=#223 id=223 data-nosnippet>223</a> } |
| <a href=#224 id=224 data-nosnippet>224</a> } |
| <a href=#225 id=225 data-nosnippet>225</a> |
| <a href=#226 id=226 data-nosnippet>226</a> <span class="comment">// Special-case `return.f()` |
| <a href=#227 id=227 data-nosnippet>227</a> </span><span class="kw">if </span><span class="self">self</span>.is_ret_like_with_no_value() && parent.is_postfix() { |
| <a href=#228 id=228 data-nosnippet>228</a> <span class="kw">return </span><span class="bool-val">false</span>; |
| <a href=#229 id=229 data-nosnippet>229</a> } |
| <a href=#230 id=230 data-nosnippet>230</a> |
| <a href=#231 id=231 data-nosnippet>231</a> <span class="comment">// Keep parens when a ret-like expr is followed by `||` or `&&`. |
| <a href=#232 id=232 data-nosnippet>232</a> // For `||`, removing parens could reparse as `<ret-like> || <closure>`. |
| <a href=#233 id=233 data-nosnippet>233</a> // For `&&`, we avoid introducing `<ret-like> && <expr>` into a binary chain. |
| <a href=#234 id=234 data-nosnippet>234</a> |
| <a href=#235 id=235 data-nosnippet>235</a> </span><span class="kw">if </span><span class="self">self</span>.precedence() == ExprPrecedence::Jump |
| <a href=#236 id=236 data-nosnippet>236</a> && <span class="kw">let </span><span class="prelude-val">Some</span>(node) = place_of_parent() |
| <a href=#237 id=237 data-nosnippet>237</a> && <span class="kw">let </span><span class="prelude-val">Some</span>(next) = next_token_of(<span class="kw-2">&</span>node) |
| <a href=#238 id=238 data-nosnippet>238</a> && <span class="macro">matches!</span>(next.kind(), <span class="macro">T!</span>[||] | <span class="macro">T!</span>[&&]) |
| <a href=#239 id=239 data-nosnippet>239</a> { |
| <a href=#240 id=240 data-nosnippet>240</a> <span class="kw">return </span><span class="bool-val">true</span>; |
| <a href=#241 id=241 data-nosnippet>241</a> } |
| <a href=#242 id=242 data-nosnippet>242</a> |
| <a href=#243 id=243 data-nosnippet>243</a> <span class="comment">// Special-case `2 as x < 3` |
| <a href=#244 id=244 data-nosnippet>244</a> </span><span class="kw">if let </span>ast::Expr::CastExpr(it) = <span class="self">self |
| <a href=#245 id=245 data-nosnippet>245</a> </span>&& <span class="kw">let </span><span class="prelude-val">Some</span>(ty) = it.ty() |
| <a href=#246 id=246 data-nosnippet>246</a> && ty.syntax().last_token().and_then(|it| ast::NameLike::cast(it.parent()<span class="question-mark">?</span>)).is_some() |
| <a href=#247 id=247 data-nosnippet>247</a> && <span class="kw">let </span><span class="prelude-val">Some</span>(node) = place_of_parent() |
| <a href=#248 id=248 data-nosnippet>248</a> && <span class="kw">let </span><span class="prelude-val">Some</span>(next) = next_token_of(<span class="kw-2">&</span>node) |
| <a href=#249 id=249 data-nosnippet>249</a> && <span class="macro">matches!</span>(next.kind(), <span class="macro">T!</span>[<] | <span class="macro">T!</span>[<<]) |
| <a href=#250 id=250 data-nosnippet>250</a> { |
| <a href=#251 id=251 data-nosnippet>251</a> <span class="kw">return </span><span class="bool-val">true</span>; |
| <a href=#252 id=252 data-nosnippet>252</a> } |
| <a href=#253 id=253 data-nosnippet>253</a> |
| <a href=#254 id=254 data-nosnippet>254</a> <span class="kw">if </span><span class="self">self</span>.is_paren_like() |
| <a href=#255 id=255 data-nosnippet>255</a> || parent.is_paren_like() |
| <a href=#256 id=256 data-nosnippet>256</a> || <span class="self">self</span>.is_prefix() |
| <a href=#257 id=257 data-nosnippet>257</a> && (parent.is_prefix() |
| <a href=#258 id=258 data-nosnippet>258</a> || !<span class="self">self</span>.is_ordered_before_parent_in_place_of(parent, place_of)) |
| <a href=#259 id=259 data-nosnippet>259</a> || <span class="self">self</span>.is_postfix() |
| <a href=#260 id=260 data-nosnippet>260</a> && (parent.is_postfix() |
| <a href=#261 id=261 data-nosnippet>261</a> || <span class="self">self</span>.is_ordered_before_parent_in_place_of(parent, place_of)) |
| <a href=#262 id=262 data-nosnippet>262</a> { |
| <a href=#263 id=263 data-nosnippet>263</a> <span class="kw">return </span><span class="bool-val">false</span>; |
| <a href=#264 id=264 data-nosnippet>264</a> } |
| <a href=#265 id=265 data-nosnippet>265</a> |
| <a href=#266 id=266 data-nosnippet>266</a> <span class="kw">let </span>(left, right, inv) = <span class="kw">match </span><span class="self">self</span>.is_ordered_before_parent_in_place_of(parent, place_of) { |
| <a href=#267 id=267 data-nosnippet>267</a> <span class="bool-val">true </span>=> (<span class="self">self</span>, parent, <span class="bool-val">false</span>), |
| <a href=#268 id=268 data-nosnippet>268</a> <span class="bool-val">false </span>=> (parent, <span class="self">self</span>, <span class="bool-val">true</span>), |
| <a href=#269 id=269 data-nosnippet>269</a> }; |
| <a href=#270 id=270 data-nosnippet>270</a> |
| <a href=#271 id=271 data-nosnippet>271</a> <span class="kw">let </span>(<span class="kw">_</span>, left_right_bp) = left.binding_power(); |
| <a href=#272 id=272 data-nosnippet>272</a> <span class="kw">let </span>(right_left_bp, <span class="kw">_</span>) = right.binding_power(); |
| <a href=#273 id=273 data-nosnippet>273</a> |
| <a href=#274 id=274 data-nosnippet>274</a> (left_right_bp < right_left_bp) ^ inv |
| <a href=#275 id=275 data-nosnippet>275</a> } |
| <a href=#276 id=276 data-nosnippet>276</a> |
| <a href=#277 id=277 data-nosnippet>277</a> <span class="kw">fn </span>needs_parens_in_stmt(<span class="kw-2">&</span><span class="self">self</span>, stmt: <span class="prelude-ty">Option</span><<span class="kw-2">&</span>ast::Stmt>) -> bool { |
| <a href=#278 id=278 data-nosnippet>278</a> <span class="kw">use </span>Expr::<span class="kw-2">*</span>; |
| <a href=#279 id=279 data-nosnippet>279</a> |
| <a href=#280 id=280 data-nosnippet>280</a> <span class="comment">// Prevent false-positives in cases like `fn x() -> u8 { ({ 0 } + 1) }`, |
| <a href=#281 id=281 data-nosnippet>281</a> // `{ { 0 } + 1 }` won't parse -- `{ 0 }` would be parsed as a self-contained stmt, |
| <a href=#282 id=282 data-nosnippet>282</a> // leaving `+ 1` as a parse error. |
| <a href=#283 id=283 data-nosnippet>283</a> </span><span class="kw">let </span><span class="kw-2">mut </span>innermost = <span class="self">self</span>.clone(); |
| <a href=#284 id=284 data-nosnippet>284</a> <span class="kw">loop </span>{ |
| <a href=#285 id=285 data-nosnippet>285</a> <span class="kw">let </span>next = <span class="kw">match </span><span class="kw-2">&</span>innermost { |
| <a href=#286 id=286 data-nosnippet>286</a> BinExpr(e) => e.lhs(), |
| <a href=#287 id=287 data-nosnippet>287</a> CallExpr(e) => e.expr(), |
| <a href=#288 id=288 data-nosnippet>288</a> CastExpr(e) => e.expr(), |
| <a href=#289 id=289 data-nosnippet>289</a> IndexExpr(e) => e.base(), |
| <a href=#290 id=290 data-nosnippet>290</a> <span class="kw">_ </span>=> <span class="kw">break</span>, |
| <a href=#291 id=291 data-nosnippet>291</a> }; |
| <a href=#292 id=292 data-nosnippet>292</a> |
| <a href=#293 id=293 data-nosnippet>293</a> <span class="kw">if let </span><span class="prelude-val">Some</span>(next) = next { |
| <a href=#294 id=294 data-nosnippet>294</a> innermost = next; |
| <a href=#295 id=295 data-nosnippet>295</a> <span class="kw">if </span>!innermost.requires_semi_to_be_stmt() { |
| <a href=#296 id=296 data-nosnippet>296</a> <span class="kw">return </span><span class="bool-val">true</span>; |
| <a href=#297 id=297 data-nosnippet>297</a> } |
| <a href=#298 id=298 data-nosnippet>298</a> } <span class="kw">else </span>{ |
| <a href=#299 id=299 data-nosnippet>299</a> <span class="kw">break</span>; |
| <a href=#300 id=300 data-nosnippet>300</a> } |
| <a href=#301 id=301 data-nosnippet>301</a> } |
| <a href=#302 id=302 data-nosnippet>302</a> |
| <a href=#303 id=303 data-nosnippet>303</a> <span class="comment">// Not every expression can be followed by `else` in the `let-else` |
| <a href=#304 id=304 data-nosnippet>304</a> </span><span class="kw">if let </span><span class="prelude-val">Some</span>(ast::Stmt::LetStmt(e)) = stmt |
| <a href=#305 id=305 data-nosnippet>305</a> && e.let_else().is_some() |
| <a href=#306 id=306 data-nosnippet>306</a> { |
| <a href=#307 id=307 data-nosnippet>307</a> <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#308 id=308 data-nosnippet>308</a> BinExpr(e) |
| <a href=#309 id=309 data-nosnippet>309</a> <span class="kw">if </span>e.op_kind() |
| <a href=#310 id=310 data-nosnippet>310</a> .map(|op| <span class="macro">matches!</span>(op, BinaryOp::LogicOp(<span class="kw">_</span>))) |
| <a href=#311 id=311 data-nosnippet>311</a> .unwrap_or(<span class="bool-val">false</span>) => |
| <a href=#312 id=312 data-nosnippet>312</a> { |
| <a href=#313 id=313 data-nosnippet>313</a> <span class="kw">return </span><span class="bool-val">true</span>; |
| <a href=#314 id=314 data-nosnippet>314</a> } |
| <a href=#315 id=315 data-nosnippet>315</a> <span class="kw">_ if </span><span class="self">self</span>.clone().trailing_brace().is_some() => <span class="kw">return </span><span class="bool-val">true</span>, |
| <a href=#316 id=316 data-nosnippet>316</a> <span class="kw">_ </span>=> {} |
| <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> |
| <a href=#320 id=320 data-nosnippet>320</a> <span class="bool-val">false |
| <a href=#321 id=321 data-nosnippet>321</a> </span>} |
| <a href=#322 id=322 data-nosnippet>322</a> |
| <a href=#323 id=323 data-nosnippet>323</a> <span class="doccomment">/// Returns left and right so-called "binding powers" of this expression. |
| <a href=#324 id=324 data-nosnippet>324</a> </span><span class="kw">fn </span>binding_power(<span class="kw-2">&</span><span class="self">self</span>) -> (u8, u8) { |
| <a href=#325 id=325 data-nosnippet>325</a> <span class="kw">use </span>ast::{ArithOp::<span class="kw-2">*</span>, BinaryOp::<span class="kw-2">*</span>, Expr::<span class="kw-2">*</span>, LogicOp::<span class="kw-2">*</span>}; |
| <a href=#326 id=326 data-nosnippet>326</a> |
| <a href=#327 id=327 data-nosnippet>327</a> <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#328 id=328 data-nosnippet>328</a> <span class="comment">// (0, 0) -- paren-like/nullary |
| <a href=#329 id=329 data-nosnippet>329</a> // (0, N) -- prefix |
| <a href=#330 id=330 data-nosnippet>330</a> // (N, 0) -- postfix |
| <a href=#331 id=331 data-nosnippet>331</a> // (N, N) -- infix, requires parens |
| <a href=#332 id=332 data-nosnippet>332</a> // (N, N+1) -- infix, left to right associative |
| <a href=#333 id=333 data-nosnippet>333</a> // (N+1, N) -- infix, right to left associative |
| <a href=#334 id=334 data-nosnippet>334</a> // N is odd |
| <a href=#335 id=335 data-nosnippet>335</a> // |
| <a href=#336 id=336 data-nosnippet>336</a> </span>ContinueExpr(<span class="kw">_</span>) => (<span class="number">0</span>, <span class="number">0</span>), |
| <a href=#337 id=337 data-nosnippet>337</a> |
| <a href=#338 id=338 data-nosnippet>338</a> ClosureExpr(<span class="kw">_</span>) | ReturnExpr(<span class="kw">_</span>) | BecomeExpr(<span class="kw">_</span>) | YieldExpr(<span class="kw">_</span>) | YeetExpr(<span class="kw">_</span>) |
| <a href=#339 id=339 data-nosnippet>339</a> | BreakExpr(<span class="kw">_</span>) | OffsetOfExpr(<span class="kw">_</span>) | FormatArgsExpr(<span class="kw">_</span>) | AsmExpr(<span class="kw">_</span>) => (<span class="number">0</span>, <span class="number">1</span>), |
| <a href=#340 id=340 data-nosnippet>340</a> |
| <a href=#341 id=341 data-nosnippet>341</a> RangeExpr(<span class="kw">_</span>) => (<span class="number">5</span>, <span class="number">5</span>), |
| <a href=#342 id=342 data-nosnippet>342</a> |
| <a href=#343 id=343 data-nosnippet>343</a> BinExpr(e) => { |
| <a href=#344 id=344 data-nosnippet>344</a> <span class="comment">// Return a dummy value if we don't know the op |
| <a href=#345 id=345 data-nosnippet>345</a> </span><span class="kw">let </span><span class="prelude-val">Some</span>(op) = e.op_kind() <span class="kw">else </span>{ <span class="kw">return </span>(<span class="number">0</span>, <span class="number">0</span>) }; |
| <a href=#346 id=346 data-nosnippet>346</a> <span class="kw">match </span>op { |
| <a href=#347 id=347 data-nosnippet>347</a> Assignment { .. } => (<span class="number">4</span>, <span class="number">3</span>), |
| <a href=#348 id=348 data-nosnippet>348</a> <span class="comment">// |
| <a href=#349 id=349 data-nosnippet>349</a> // Ranges are here in order :) |
| <a href=#350 id=350 data-nosnippet>350</a> // |
| <a href=#351 id=351 data-nosnippet>351</a> </span>LogicOp(op) => <span class="kw">match </span>op { |
| <a href=#352 id=352 data-nosnippet>352</a> Or => (<span class="number">7</span>, <span class="number">8</span>), |
| <a href=#353 id=353 data-nosnippet>353</a> And => (<span class="number">9</span>, <span class="number">10</span>), |
| <a href=#354 id=354 data-nosnippet>354</a> }, |
| <a href=#355 id=355 data-nosnippet>355</a> CmpOp(<span class="kw">_</span>) => (<span class="number">11</span>, <span class="number">11</span>), |
| <a href=#356 id=356 data-nosnippet>356</a> ArithOp(op) => <span class="kw">match </span>op { |
| <a href=#357 id=357 data-nosnippet>357</a> BitOr => (<span class="number">13</span>, <span class="number">14</span>), |
| <a href=#358 id=358 data-nosnippet>358</a> BitXor => (<span class="number">15</span>, <span class="number">16</span>), |
| <a href=#359 id=359 data-nosnippet>359</a> BitAnd => (<span class="number">17</span>, <span class="number">18</span>), |
| <a href=#360 id=360 data-nosnippet>360</a> Shl | Shr => (<span class="number">19</span>, <span class="number">20</span>), |
| <a href=#361 id=361 data-nosnippet>361</a> Add | Sub => (<span class="number">21</span>, <span class="number">22</span>), |
| <a href=#362 id=362 data-nosnippet>362</a> Mul | Div | Rem => (<span class="number">23</span>, <span class="number">24</span>), |
| <a href=#363 id=363 data-nosnippet>363</a> }, |
| <a href=#364 id=364 data-nosnippet>364</a> } |
| <a href=#365 id=365 data-nosnippet>365</a> } |
| <a href=#366 id=366 data-nosnippet>366</a> |
| <a href=#367 id=367 data-nosnippet>367</a> CastExpr(<span class="kw">_</span>) => (<span class="number">25</span>, <span class="number">26</span>), |
| <a href=#368 id=368 data-nosnippet>368</a> |
| <a href=#369 id=369 data-nosnippet>369</a> RefExpr(<span class="kw">_</span>) | LetExpr(<span class="kw">_</span>) | PrefixExpr(<span class="kw">_</span>) => (<span class="number">0</span>, <span class="number">27</span>), |
| <a href=#370 id=370 data-nosnippet>370</a> |
| <a href=#371 id=371 data-nosnippet>371</a> AwaitExpr(<span class="kw">_</span>) | CallExpr(<span class="kw">_</span>) | MethodCallExpr(<span class="kw">_</span>) | IndexExpr(<span class="kw">_</span>) | TryExpr(<span class="kw">_</span>) |
| <a href=#372 id=372 data-nosnippet>372</a> | MacroExpr(<span class="kw">_</span>) => (<span class="number">29</span>, <span class="number">0</span>), |
| <a href=#373 id=373 data-nosnippet>373</a> |
| <a href=#374 id=374 data-nosnippet>374</a> FieldExpr(<span class="kw">_</span>) => (<span class="number">31</span>, <span class="number">32</span>), |
| <a href=#375 id=375 data-nosnippet>375</a> |
| <a href=#376 id=376 data-nosnippet>376</a> ArrayExpr(<span class="kw">_</span>) | TupleExpr(<span class="kw">_</span>) | Literal(<span class="kw">_</span>) | PathExpr(<span class="kw">_</span>) | ParenExpr(<span class="kw">_</span>) | IfExpr(<span class="kw">_</span>) |
| <a href=#377 id=377 data-nosnippet>377</a> | WhileExpr(<span class="kw">_</span>) | ForExpr(<span class="kw">_</span>) | LoopExpr(<span class="kw">_</span>) | MatchExpr(<span class="kw">_</span>) | BlockExpr(<span class="kw">_</span>) |
| <a href=#378 id=378 data-nosnippet>378</a> | RecordExpr(<span class="kw">_</span>) | UnderscoreExpr(<span class="kw">_</span>) => (<span class="number">0</span>, <span class="number">0</span>), |
| <a href=#379 id=379 data-nosnippet>379</a> } |
| <a href=#380 id=380 data-nosnippet>380</a> } |
| <a href=#381 id=381 data-nosnippet>381</a> |
| <a href=#382 id=382 data-nosnippet>382</a> <span class="kw">fn </span>is_paren_like(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#383 id=383 data-nosnippet>383</a> <span class="macro">matches!</span>(<span class="self">self</span>.binding_power(), (<span class="number">0</span>, <span class="number">0</span>)) |
| <a href=#384 id=384 data-nosnippet>384</a> } |
| <a href=#385 id=385 data-nosnippet>385</a> |
| <a href=#386 id=386 data-nosnippet>386</a> <span class="kw">fn </span>is_prefix(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#387 id=387 data-nosnippet>387</a> <span class="macro">matches!</span>(<span class="self">self</span>.binding_power(), (<span class="number">0</span>, <span class="number">1</span>..)) |
| <a href=#388 id=388 data-nosnippet>388</a> } |
| <a href=#389 id=389 data-nosnippet>389</a> |
| <a href=#390 id=390 data-nosnippet>390</a> <span class="kw">fn </span>is_postfix(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#391 id=391 data-nosnippet>391</a> <span class="macro">matches!</span>(<span class="self">self</span>.binding_power(), (<span class="number">1</span>.., <span class="number">0</span>)) |
| <a href=#392 id=392 data-nosnippet>392</a> } |
| <a href=#393 id=393 data-nosnippet>393</a> |
| <a href=#394 id=394 data-nosnippet>394</a> <span class="doccomment">/// Returns `true` if this expression can't be a standalone statement. |
| <a href=#395 id=395 data-nosnippet>395</a> </span><span class="kw">fn </span>requires_semi_to_be_stmt(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#396 id=396 data-nosnippet>396</a> <span class="kw">use </span>Expr::<span class="kw-2">*</span>; |
| <a href=#397 id=397 data-nosnippet>397</a> !<span class="macro">matches!</span>( |
| <a href=#398 id=398 data-nosnippet>398</a> <span class="self">self</span>, |
| <a href=#399 id=399 data-nosnippet>399</a> IfExpr(..) | MatchExpr(..) | BlockExpr(..) | WhileExpr(..) | LoopExpr(..) | ForExpr(..) |
| <a href=#400 id=400 data-nosnippet>400</a> ) |
| <a href=#401 id=401 data-nosnippet>401</a> } |
| <a href=#402 id=402 data-nosnippet>402</a> |
| <a href=#403 id=403 data-nosnippet>403</a> <span class="doccomment">/// If an expression ends with `}`, returns the innermost expression ending in this `}`. |
| <a href=#404 id=404 data-nosnippet>404</a> </span><span class="kw">fn </span>trailing_brace(<span class="kw-2">mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><Expr> { |
| <a href=#405 id=405 data-nosnippet>405</a> <span class="kw">use </span>Expr::<span class="kw-2">*</span>; |
| <a href=#406 id=406 data-nosnippet>406</a> |
| <a href=#407 id=407 data-nosnippet>407</a> <span class="kw">loop </span>{ |
| <a href=#408 id=408 data-nosnippet>408</a> <span class="kw">let </span>rhs = <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#409 id=409 data-nosnippet>409</a> RefExpr(e) => e.expr(), |
| <a href=#410 id=410 data-nosnippet>410</a> BinExpr(e) => e.rhs(), |
| <a href=#411 id=411 data-nosnippet>411</a> BreakExpr(e) => e.expr(), |
| <a href=#412 id=412 data-nosnippet>412</a> LetExpr(e) => e.expr(), |
| <a href=#413 id=413 data-nosnippet>413</a> RangeExpr(e) => e.end(), |
| <a href=#414 id=414 data-nosnippet>414</a> ReturnExpr(e) => e.expr(), |
| <a href=#415 id=415 data-nosnippet>415</a> PrefixExpr(e) => e.expr(), |
| <a href=#416 id=416 data-nosnippet>416</a> YieldExpr(e) => e.expr(), |
| <a href=#417 id=417 data-nosnippet>417</a> ClosureExpr(e) => e.body(), |
| <a href=#418 id=418 data-nosnippet>418</a> |
| <a href=#419 id=419 data-nosnippet>419</a> BlockExpr(..) | ForExpr(..) | IfExpr(..) | LoopExpr(..) | MatchExpr(..) |
| <a href=#420 id=420 data-nosnippet>420</a> | RecordExpr(..) | WhileExpr(..) => <span class="kw">break </span><span class="prelude-val">Some</span>(<span class="self">self</span>), |
| <a href=#421 id=421 data-nosnippet>421</a> <span class="kw">_ </span>=> <span class="kw">break </span><span class="prelude-val">None</span>, |
| <a href=#422 id=422 data-nosnippet>422</a> }; |
| <a href=#423 id=423 data-nosnippet>423</a> |
| <a href=#424 id=424 data-nosnippet>424</a> <span class="self">self </span>= rhs<span class="question-mark">?</span>; |
| <a href=#425 id=425 data-nosnippet>425</a> } |
| <a href=#426 id=426 data-nosnippet>426</a> } |
| <a href=#427 id=427 data-nosnippet>427</a> |
| <a href=#428 id=428 data-nosnippet>428</a> <span class="doccomment">/// Expressions that syntactically contain an "exterior" struct literal i.e., not surrounded by any |
| <a href=#429 id=429 data-nosnippet>429</a> /// parens or other delimiters, e.g., `X { y: 1 }`, `X { y: 1 }.method()`, `foo == X { y: 1 }` and |
| <a href=#430 id=430 data-nosnippet>430</a> /// `X { y: 1 } == foo` all do, but `(X { y: 1 }) == foo` does not. |
| <a href=#431 id=431 data-nosnippet>431</a> </span><span class="kw">fn </span>contains_exterior_struct_lit(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#432 id=432 data-nosnippet>432</a> <span class="kw">return </span>contains_exterior_struct_lit_inner(<span class="self">self</span>).is_some(); |
| <a href=#433 id=433 data-nosnippet>433</a> |
| <a href=#434 id=434 data-nosnippet>434</a> <span class="kw">fn </span>contains_exterior_struct_lit_inner(expr: <span class="kw-2">&</span>Expr) -> <span class="prelude-ty">Option</span><()> { |
| <a href=#435 id=435 data-nosnippet>435</a> <span class="kw">use </span>Expr::<span class="kw-2">*</span>; |
| <a href=#436 id=436 data-nosnippet>436</a> |
| <a href=#437 id=437 data-nosnippet>437</a> <span class="kw">match </span>expr { |
| <a href=#438 id=438 data-nosnippet>438</a> RecordExpr(..) => <span class="prelude-val">Some</span>(()), |
| <a href=#439 id=439 data-nosnippet>439</a> |
| <a href=#440 id=440 data-nosnippet>440</a> <span class="comment">// X { y: 1 } + X { y: 2 } |
| <a href=#441 id=441 data-nosnippet>441</a> </span>BinExpr(e) => e |
| <a href=#442 id=442 data-nosnippet>442</a> .lhs() |
| <a href=#443 id=443 data-nosnippet>443</a> .as_ref() |
| <a href=#444 id=444 data-nosnippet>444</a> .and_then(contains_exterior_struct_lit_inner) |
| <a href=#445 id=445 data-nosnippet>445</a> .or_else(|| e.rhs().as_ref().and_then(contains_exterior_struct_lit_inner)), |
| <a href=#446 id=446 data-nosnippet>446</a> |
| <a href=#447 id=447 data-nosnippet>447</a> <span class="comment">// `&X { y: 1 }`, `X { y: 1 }.y`, `X { y: 1 }.bar(...)`, etc |
| <a href=#448 id=448 data-nosnippet>448</a> </span>IndexExpr(e) => contains_exterior_struct_lit_inner(<span class="kw-2">&</span>e.base()<span class="question-mark">?</span>), |
| <a href=#449 id=449 data-nosnippet>449</a> AwaitExpr(e) => contains_exterior_struct_lit_inner(<span class="kw-2">&</span>e.expr()<span class="question-mark">?</span>), |
| <a href=#450 id=450 data-nosnippet>450</a> PrefixExpr(e) => contains_exterior_struct_lit_inner(<span class="kw-2">&</span>e.expr()<span class="question-mark">?</span>), |
| <a href=#451 id=451 data-nosnippet>451</a> CastExpr(e) => contains_exterior_struct_lit_inner(<span class="kw-2">&</span>e.expr()<span class="question-mark">?</span>), |
| <a href=#452 id=452 data-nosnippet>452</a> FieldExpr(e) => contains_exterior_struct_lit_inner(<span class="kw-2">&</span>e.expr()<span class="question-mark">?</span>), |
| <a href=#453 id=453 data-nosnippet>453</a> MethodCallExpr(e) => contains_exterior_struct_lit_inner(<span class="kw-2">&</span>e.receiver()<span class="question-mark">?</span>), |
| <a href=#454 id=454 data-nosnippet>454</a> |
| <a href=#455 id=455 data-nosnippet>455</a> <span class="kw">_ </span>=> <span class="prelude-val">None</span>, |
| <a href=#456 id=456 data-nosnippet>456</a> } |
| <a href=#457 id=457 data-nosnippet>457</a> } |
| <a href=#458 id=458 data-nosnippet>458</a> } |
| <a href=#459 id=459 data-nosnippet>459</a> |
| <a href=#460 id=460 data-nosnippet>460</a> <span class="doccomment">/// Returns true if self is one of `return`, `break`, `continue` or `yield` with **no associated value**. |
| <a href=#461 id=461 data-nosnippet>461</a> </span><span class="kw">pub fn </span>is_ret_like_with_no_value(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#462 id=462 data-nosnippet>462</a> <span class="kw">use </span>Expr::<span class="kw-2">*</span>; |
| <a href=#463 id=463 data-nosnippet>463</a> |
| <a href=#464 id=464 data-nosnippet>464</a> <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#465 id=465 data-nosnippet>465</a> ReturnExpr(e) => e.expr().is_none(), |
| <a href=#466 id=466 data-nosnippet>466</a> BreakExpr(e) => e.expr().is_none(), |
| <a href=#467 id=467 data-nosnippet>467</a> ContinueExpr(<span class="kw">_</span>) => <span class="bool-val">true</span>, |
| <a href=#468 id=468 data-nosnippet>468</a> YieldExpr(e) => e.expr().is_none(), |
| <a href=#469 id=469 data-nosnippet>469</a> BecomeExpr(e) => e.expr().is_none(), |
| <a href=#470 id=470 data-nosnippet>470</a> <span class="kw">_ </span>=> <span class="bool-val">false</span>, |
| <a href=#471 id=471 data-nosnippet>471</a> } |
| <a href=#472 id=472 data-nosnippet>472</a> } |
| <a href=#473 id=473 data-nosnippet>473</a> |
| <a href=#474 id=474 data-nosnippet>474</a> <span class="kw">fn </span>is_ordered_before_parent_in_place_of(<span class="kw-2">&</span><span class="self">self</span>, parent: <span class="kw-2">&</span>Expr, place_of: <span class="kw-2">&</span>SyntaxNode) -> bool { |
| <a href=#475 id=475 data-nosnippet>475</a> <span class="kw">use </span>Expr::<span class="kw-2">*</span>; |
| <a href=#476 id=476 data-nosnippet>476</a> <span class="kw">use </span>rowan::TextSize; |
| <a href=#477 id=477 data-nosnippet>477</a> |
| <a href=#478 id=478 data-nosnippet>478</a> <span class="kw">let </span>self_range = <span class="self">self</span>.syntax().text_range(); |
| <a href=#479 id=479 data-nosnippet>479</a> <span class="kw">let </span>place_of_range = place_of.text_range(); |
| <a href=#480 id=480 data-nosnippet>480</a> |
| <a href=#481 id=481 data-nosnippet>481</a> <span class="kw">let </span>self_order_adjusted = order(<span class="self">self</span>) - self_range.start() + place_of_range.start(); |
| <a href=#482 id=482 data-nosnippet>482</a> |
| <a href=#483 id=483 data-nosnippet>483</a> <span class="kw">let </span>parent_order = order(parent); |
| <a href=#484 id=484 data-nosnippet>484</a> <span class="kw">let </span>parent_order_adjusted = <span class="kw">if </span>parent_order <= place_of_range.start() { |
| <a href=#485 id=485 data-nosnippet>485</a> parent_order |
| <a href=#486 id=486 data-nosnippet>486</a> } <span class="kw">else if </span>parent_order >= place_of_range.end() { |
| <a href=#487 id=487 data-nosnippet>487</a> parent_order - place_of_range.len() + self_range.len() |
| <a href=#488 id=488 data-nosnippet>488</a> } <span class="kw">else </span>{ |
| <a href=#489 id=489 data-nosnippet>489</a> <span class="kw">return </span><span class="bool-val">false</span>; |
| <a href=#490 id=490 data-nosnippet>490</a> }; |
| <a href=#491 id=491 data-nosnippet>491</a> |
| <a href=#492 id=492 data-nosnippet>492</a> <span class="kw">return </span>self_order_adjusted < parent_order_adjusted; |
| <a href=#493 id=493 data-nosnippet>493</a> |
| <a href=#494 id=494 data-nosnippet>494</a> <span class="doccomment">/// Returns text range that can be used to compare two expression for order (which goes first). |
| <a href=#495 id=495 data-nosnippet>495</a> </span><span class="kw">fn </span>order(this: <span class="kw-2">&</span>Expr) -> TextSize { |
| <a href=#496 id=496 data-nosnippet>496</a> <span class="comment">// For non-paren-like operators: get the operator itself |
| <a href=#497 id=497 data-nosnippet>497</a> </span><span class="kw">let </span>token = <span class="kw">match </span>this { |
| <a href=#498 id=498 data-nosnippet>498</a> RangeExpr(e) => e.op_token(), |
| <a href=#499 id=499 data-nosnippet>499</a> BinExpr(e) => e.op_token(), |
| <a href=#500 id=500 data-nosnippet>500</a> CastExpr(e) => e.as_token(), |
| <a href=#501 id=501 data-nosnippet>501</a> FieldExpr(e) => e.dot_token(), |
| <a href=#502 id=502 data-nosnippet>502</a> AwaitExpr(e) => e.dot_token(), |
| <a href=#503 id=503 data-nosnippet>503</a> BreakExpr(e) => e.break_token(), |
| <a href=#504 id=504 data-nosnippet>504</a> CallExpr(e) => e.arg_list().and_then(|args| args.l_paren_token()), |
| <a href=#505 id=505 data-nosnippet>505</a> ClosureExpr(e) => e.param_list().and_then(|params| params.l_paren_token()), |
| <a href=#506 id=506 data-nosnippet>506</a> ContinueExpr(e) => e.continue_token(), |
| <a href=#507 id=507 data-nosnippet>507</a> IndexExpr(e) => e.l_brack_token(), |
| <a href=#508 id=508 data-nosnippet>508</a> MethodCallExpr(e) => e.dot_token(), |
| <a href=#509 id=509 data-nosnippet>509</a> PrefixExpr(e) => e.op_token(), |
| <a href=#510 id=510 data-nosnippet>510</a> RefExpr(e) => e.amp_token(), |
| <a href=#511 id=511 data-nosnippet>511</a> ReturnExpr(e) => e.return_token(), |
| <a href=#512 id=512 data-nosnippet>512</a> BecomeExpr(e) => e.become_token(), |
| <a href=#513 id=513 data-nosnippet>513</a> TryExpr(e) => e.question_mark_token(), |
| <a href=#514 id=514 data-nosnippet>514</a> YieldExpr(e) => e.yield_token(), |
| <a href=#515 id=515 data-nosnippet>515</a> YeetExpr(e) => e.do_token(), |
| <a href=#516 id=516 data-nosnippet>516</a> LetExpr(e) => e.let_token(), |
| <a href=#517 id=517 data-nosnippet>517</a> OffsetOfExpr(e) => e.builtin_token(), |
| <a href=#518 id=518 data-nosnippet>518</a> FormatArgsExpr(e) => e.builtin_token(), |
| <a href=#519 id=519 data-nosnippet>519</a> AsmExpr(e) => e.builtin_token(), |
| <a href=#520 id=520 data-nosnippet>520</a> ArrayExpr(<span class="kw">_</span>) | TupleExpr(<span class="kw">_</span>) | Literal(<span class="kw">_</span>) | PathExpr(<span class="kw">_</span>) | ParenExpr(<span class="kw">_</span>) |
| <a href=#521 id=521 data-nosnippet>521</a> | IfExpr(<span class="kw">_</span>) | WhileExpr(<span class="kw">_</span>) | ForExpr(<span class="kw">_</span>) | LoopExpr(<span class="kw">_</span>) | MatchExpr(<span class="kw">_</span>) |
| <a href=#522 id=522 data-nosnippet>522</a> | BlockExpr(<span class="kw">_</span>) | RecordExpr(<span class="kw">_</span>) | UnderscoreExpr(<span class="kw">_</span>) | MacroExpr(<span class="kw">_</span>) => <span class="prelude-val">None</span>, |
| <a href=#523 id=523 data-nosnippet>523</a> }; |
| <a href=#524 id=524 data-nosnippet>524</a> |
| <a href=#525 id=525 data-nosnippet>525</a> token.map(|t| t.text_range()).unwrap_or_else(|| this.syntax().text_range()).start() |
| <a href=#526 id=526 data-nosnippet>526</a> } |
| <a href=#527 id=527 data-nosnippet>527</a> } |
| <a href=#528 id=528 data-nosnippet>528</a> |
| <a href=#529 id=529 data-nosnippet>529</a> <span class="kw">fn </span>child_is_followed_by_a_block(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#530 id=530 data-nosnippet>530</a> <span class="kw">use </span>Expr::<span class="kw-2">*</span>; |
| <a href=#531 id=531 data-nosnippet>531</a> |
| <a href=#532 id=532 data-nosnippet>532</a> <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#533 id=533 data-nosnippet>533</a> ArrayExpr(<span class="kw">_</span>) | AwaitExpr(<span class="kw">_</span>) | BlockExpr(<span class="kw">_</span>) | CallExpr(<span class="kw">_</span>) | CastExpr(<span class="kw">_</span>) |
| <a href=#534 id=534 data-nosnippet>534</a> | ClosureExpr(<span class="kw">_</span>) | FieldExpr(<span class="kw">_</span>) | IndexExpr(<span class="kw">_</span>) | Literal(<span class="kw">_</span>) | LoopExpr(<span class="kw">_</span>) |
| <a href=#535 id=535 data-nosnippet>535</a> | MacroExpr(<span class="kw">_</span>) | MethodCallExpr(<span class="kw">_</span>) | ParenExpr(<span class="kw">_</span>) | PathExpr(<span class="kw">_</span>) | RecordExpr(<span class="kw">_</span>) |
| <a href=#536 id=536 data-nosnippet>536</a> | TryExpr(<span class="kw">_</span>) | TupleExpr(<span class="kw">_</span>) | UnderscoreExpr(<span class="kw">_</span>) | OffsetOfExpr(<span class="kw">_</span>) |
| <a href=#537 id=537 data-nosnippet>537</a> | FormatArgsExpr(<span class="kw">_</span>) | AsmExpr(<span class="kw">_</span>) => <span class="bool-val">false</span>, |
| <a href=#538 id=538 data-nosnippet>538</a> |
| <a href=#539 id=539 data-nosnippet>539</a> <span class="comment">// For BinExpr and RangeExpr this is technically wrong -- the child can be on the left... |
| <a href=#540 id=540 data-nosnippet>540</a> </span>BinExpr(<span class="kw">_</span>) | RangeExpr(<span class="kw">_</span>) | BreakExpr(<span class="kw">_</span>) | ContinueExpr(<span class="kw">_</span>) | PrefixExpr(<span class="kw">_</span>) |
| <a href=#541 id=541 data-nosnippet>541</a> | RefExpr(<span class="kw">_</span>) | ReturnExpr(<span class="kw">_</span>) | BecomeExpr(<span class="kw">_</span>) | YieldExpr(<span class="kw">_</span>) | YeetExpr(<span class="kw">_</span>) |
| <a href=#542 id=542 data-nosnippet>542</a> | LetExpr(<span class="kw">_</span>) => <span class="self">self |
| <a href=#543 id=543 data-nosnippet>543</a> </span>.syntax() |
| <a href=#544 id=544 data-nosnippet>544</a> .parent() |
| <a href=#545 id=545 data-nosnippet>545</a> .and_then(Expr::cast) |
| <a href=#546 id=546 data-nosnippet>546</a> .map(|e| e.child_is_followed_by_a_block()) |
| <a href=#547 id=547 data-nosnippet>547</a> .unwrap_or(<span class="bool-val">false</span>), |
| <a href=#548 id=548 data-nosnippet>548</a> |
| <a href=#549 id=549 data-nosnippet>549</a> ForExpr(<span class="kw">_</span>) | IfExpr(<span class="kw">_</span>) | MatchExpr(<span class="kw">_</span>) | WhileExpr(<span class="kw">_</span>) => <span class="bool-val">true</span>, |
| <a href=#550 id=550 data-nosnippet>550</a> } |
| <a href=#551 id=551 data-nosnippet>551</a> } |
| <a href=#552 id=552 data-nosnippet>552</a>} |
| </code></pre></div></section></main></body></html> |
