| <!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 `lib/ungrammar/src/parser.rs`."><title>parser.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-77263533.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="ungrammar" data-themes="" data-resource-suffix="" data-rustdoc-version="1.94.0 (4a4ef493e 2026-03-02)" data-channel="1.94.0" data-search-js="search-9e2438ea.js" data-stringdex-js="stringdex-b897f86f.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-7bab91a1.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-ffcac47a.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">ungrammar/</div>parser.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">//! Simple hand-written ungrammar parser. |
| <a href=#2 id=2 data-nosnippet>2</a></span><span class="attr">#![allow(clippy::disallowed_types)] |
| <a href=#3 id=3 data-nosnippet>3</a></span><span class="kw">use </span>std::collections::HashMap; |
| <a href=#4 id=4 data-nosnippet>4</a> |
| <a href=#5 id=5 data-nosnippet>5</a><span class="kw">use </span>crate::{ |
| <a href=#6 id=6 data-nosnippet>6</a> Grammar, Node, NodeData, Rule, Token, TokenData, |
| <a href=#7 id=7 data-nosnippet>7</a> error::{<span class="prelude-ty">Result</span>, format_err}, |
| <a href=#8 id=8 data-nosnippet>8</a> lexer::{<span class="self">self</span>, TokenKind}, |
| <a href=#9 id=9 data-nosnippet>9</a>}; |
| <a href=#10 id=10 data-nosnippet>10</a> |
| <a href=#11 id=11 data-nosnippet>11</a><span class="macro">macro_rules!</span> bail { |
| <a href=#12 id=12 data-nosnippet>12</a> (<span class="macro-nonterminal">$loc</span>:expr, $(<span class="macro-nonterminal">$tt</span>:tt)<span class="kw-2">*</span>) => {{ |
| <a href=#13 id=13 data-nosnippet>13</a> <span class="kw">let </span>err = <span class="macro-nonterminal">$crate::error::format_err</span>!($(<span class="macro-nonterminal">$tt</span>)<span class="kw-2">*</span>) |
| <a href=#14 id=14 data-nosnippet>14</a> .with_location(<span class="macro-nonterminal">$loc</span>); |
| <a href=#15 id=15 data-nosnippet>15</a> <span class="kw">return </span><span class="prelude-val">Err</span>(err); |
| <a href=#16 id=16 data-nosnippet>16</a> }}; |
| <a href=#17 id=17 data-nosnippet>17</a>} |
| <a href=#18 id=18 data-nosnippet>18</a> |
| <a href=#19 id=19 data-nosnippet>19</a><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>parse(tokens: Vec<lexer::Token>) -> <span class="prelude-ty">Result</span><Grammar> { |
| <a href=#20 id=20 data-nosnippet>20</a> <span class="kw">let </span><span class="kw-2">mut </span>p = Parser::new(tokens); |
| <a href=#21 id=21 data-nosnippet>21</a> <span class="kw">while </span>!p.is_eof() { |
| <a href=#22 id=22 data-nosnippet>22</a> node(<span class="kw-2">&mut </span>p)<span class="question-mark">?</span>; |
| <a href=#23 id=23 data-nosnippet>23</a> } |
| <a href=#24 id=24 data-nosnippet>24</a> p.finish() |
| <a href=#25 id=25 data-nosnippet>25</a>} |
| <a href=#26 id=26 data-nosnippet>26</a> |
| <a href=#27 id=27 data-nosnippet>27</a><span class="attr">#[derive(Default)] |
| <a href=#28 id=28 data-nosnippet>28</a></span><span class="kw">struct </span>Parser { |
| <a href=#29 id=29 data-nosnippet>29</a> grammar: Grammar, |
| <a href=#30 id=30 data-nosnippet>30</a> tokens: Vec<lexer::Token>, |
| <a href=#31 id=31 data-nosnippet>31</a> node_table: HashMap<String, Node>, |
| <a href=#32 id=32 data-nosnippet>32</a> token_table: HashMap<String, Token>, |
| <a href=#33 id=33 data-nosnippet>33</a>} |
| <a href=#34 id=34 data-nosnippet>34</a> |
| <a href=#35 id=35 data-nosnippet>35</a><span class="kw">const </span>DUMMY_RULE: Rule = Rule::Node(Node(!<span class="number">0</span>)); |
| <a href=#36 id=36 data-nosnippet>36</a> |
| <a href=#37 id=37 data-nosnippet>37</a><span class="kw">impl </span>Parser { |
| <a href=#38 id=38 data-nosnippet>38</a> <span class="kw">fn </span>new(<span class="kw-2">mut </span>tokens: Vec<lexer::Token>) -> Parser { |
| <a href=#39 id=39 data-nosnippet>39</a> tokens.reverse(); |
| <a href=#40 id=40 data-nosnippet>40</a> Parser { tokens, ..Parser::default() } |
| <a href=#41 id=41 data-nosnippet>41</a> } |
| <a href=#42 id=42 data-nosnippet>42</a> |
| <a href=#43 id=43 data-nosnippet>43</a> <span class="kw">fn </span>peek(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>lexer::Token> { |
| <a href=#44 id=44 data-nosnippet>44</a> <span class="self">self</span>.peek_n(<span class="number">0</span>) |
| <a href=#45 id=45 data-nosnippet>45</a> } |
| <a href=#46 id=46 data-nosnippet>46</a> <span class="kw">fn </span>peek_n(<span class="kw-2">&</span><span class="self">self</span>, n: usize) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>lexer::Token> { |
| <a href=#47 id=47 data-nosnippet>47</a> <span class="self">self</span>.tokens.iter().nth_back(n) |
| <a href=#48 id=48 data-nosnippet>48</a> } |
| <a href=#49 id=49 data-nosnippet>49</a> <span class="kw">fn </span>bump(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><lexer::Token> { |
| <a href=#50 id=50 data-nosnippet>50</a> <span class="self">self</span>.tokens.pop().ok_or_else(|| <span class="macro">format_err!</span>(<span class="string">"unexpected EOF"</span>)) |
| <a href=#51 id=51 data-nosnippet>51</a> } |
| <a href=#52 id=52 data-nosnippet>52</a> <span class="kw">fn </span>expect(<span class="kw-2">&mut </span><span class="self">self</span>, kind: TokenKind, what: <span class="kw-2">&</span>str) -> <span class="prelude-ty">Result</span><()> { |
| <a href=#53 id=53 data-nosnippet>53</a> <span class="kw">let </span>token = <span class="self">self</span>.bump()<span class="question-mark">?</span>; |
| <a href=#54 id=54 data-nosnippet>54</a> <span class="kw">if </span>token.<span class="macro">kind !</span>= kind { |
| <a href=#55 id=55 data-nosnippet>55</a> <span class="macro">bail!</span>(token.loc, <span class="string">"unexpected token, expected `{}`"</span>, what); |
| <a href=#56 id=56 data-nosnippet>56</a> } |
| <a href=#57 id=57 data-nosnippet>57</a> <span class="prelude-val">Ok</span>(()) |
| <a href=#58 id=58 data-nosnippet>58</a> } |
| <a href=#59 id=59 data-nosnippet>59</a> <span class="kw">fn </span>is_eof(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <a href=#60 id=60 data-nosnippet>60</a> <span class="self">self</span>.tokens.is_empty() |
| <a href=#61 id=61 data-nosnippet>61</a> } |
| <a href=#62 id=62 data-nosnippet>62</a> <span class="kw">fn </span>finish(<span class="self">self</span>) -> <span class="prelude-ty">Result</span><Grammar> { |
| <a href=#63 id=63 data-nosnippet>63</a> <span class="kw">for </span>node_data <span class="kw">in </span><span class="kw-2">&</span><span class="self">self</span>.grammar.nodes { |
| <a href=#64 id=64 data-nosnippet>64</a> <span class="kw">if </span><span class="macro">matches!</span>(node_data.rule, DUMMY_RULE) { |
| <a href=#65 id=65 data-nosnippet>65</a> <span class="macro">crate::error::bail!</span>(<span class="string">"Undefined node: {}"</span>, node_data.name) |
| <a href=#66 id=66 data-nosnippet>66</a> } |
| <a href=#67 id=67 data-nosnippet>67</a> } |
| <a href=#68 id=68 data-nosnippet>68</a> <span class="prelude-val">Ok</span>(<span class="self">self</span>.grammar) |
| <a href=#69 id=69 data-nosnippet>69</a> } |
| <a href=#70 id=70 data-nosnippet>70</a> <span class="kw">fn </span>intern_node(<span class="kw-2">&mut </span><span class="self">self</span>, name: String) -> Node { |
| <a href=#71 id=71 data-nosnippet>71</a> <span class="kw">let </span>len = <span class="self">self</span>.node_table.len(); |
| <a href=#72 id=72 data-nosnippet>72</a> <span class="kw">let </span>grammar = <span class="kw-2">&mut </span><span class="self">self</span>.grammar; |
| <a href=#73 id=73 data-nosnippet>73</a> <span class="kw-2">*</span><span class="self">self</span>.node_table.entry(name.clone()).or_insert_with(|| { |
| <a href=#74 id=74 data-nosnippet>74</a> grammar.nodes.push(NodeData { name, rule: DUMMY_RULE }); |
| <a href=#75 id=75 data-nosnippet>75</a> Node(len) |
| <a href=#76 id=76 data-nosnippet>76</a> }) |
| <a href=#77 id=77 data-nosnippet>77</a> } |
| <a href=#78 id=78 data-nosnippet>78</a> <span class="kw">fn </span>intern_token(<span class="kw-2">&mut </span><span class="self">self</span>, name: String) -> Token { |
| <a href=#79 id=79 data-nosnippet>79</a> <span class="kw">let </span>len = <span class="self">self</span>.token_table.len(); |
| <a href=#80 id=80 data-nosnippet>80</a> <span class="kw">let </span>grammar = <span class="kw-2">&mut </span><span class="self">self</span>.grammar; |
| <a href=#81 id=81 data-nosnippet>81</a> <span class="kw-2">*</span><span class="self">self</span>.token_table.entry(name.clone()).or_insert_with(|| { |
| <a href=#82 id=82 data-nosnippet>82</a> grammar.tokens.push(TokenData { name }); |
| <a href=#83 id=83 data-nosnippet>83</a> Token(len) |
| <a href=#84 id=84 data-nosnippet>84</a> }) |
| <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> |
| <a href=#88 id=88 data-nosnippet>88</a><span class="kw">fn </span>node(p: <span class="kw-2">&mut </span>Parser) -> <span class="prelude-ty">Result</span><()> { |
| <a href=#89 id=89 data-nosnippet>89</a> <span class="kw">let </span>token = p.bump()<span class="question-mark">?</span>; |
| <a href=#90 id=90 data-nosnippet>90</a> <span class="kw">let </span>node = <span class="kw">match </span>token.kind { |
| <a href=#91 id=91 data-nosnippet>91</a> TokenKind::Node(it) => p.intern_node(it), |
| <a href=#92 id=92 data-nosnippet>92</a> <span class="kw">_ </span>=> <span class="macro">bail!</span>(token.loc, <span class="string">"expected ident"</span>), |
| <a href=#93 id=93 data-nosnippet>93</a> }; |
| <a href=#94 id=94 data-nosnippet>94</a> p.expect(TokenKind::Eq, <span class="string">"="</span>)<span class="question-mark">?</span>; |
| <a href=#95 id=95 data-nosnippet>95</a> <span class="kw">if </span>!<span class="macro">matches!</span>(p.grammar[node].rule, DUMMY_RULE) { |
| <a href=#96 id=96 data-nosnippet>96</a> <span class="macro">bail!</span>(token.loc, <span class="string">"duplicate rule: `{}`"</span>, p.grammar[node].name) |
| <a href=#97 id=97 data-nosnippet>97</a> } |
| <a href=#98 id=98 data-nosnippet>98</a> |
| <a href=#99 id=99 data-nosnippet>99</a> <span class="kw">let </span>rule = rule(p)<span class="question-mark">?</span>; |
| <a href=#100 id=100 data-nosnippet>100</a> p.grammar.nodes[node.<span class="number">0</span>].rule = rule; |
| <a href=#101 id=101 data-nosnippet>101</a> <span class="prelude-val">Ok</span>(()) |
| <a href=#102 id=102 data-nosnippet>102</a>} |
| <a href=#103 id=103 data-nosnippet>103</a> |
| <a href=#104 id=104 data-nosnippet>104</a><span class="kw">fn </span>rule(p: <span class="kw-2">&mut </span>Parser) -> <span class="prelude-ty">Result</span><Rule> { |
| <a href=#105 id=105 data-nosnippet>105</a> <span class="kw">if let </span><span class="prelude-val">Some</span>(lexer::Token { kind: TokenKind::Pipe, loc }) = p.peek() { |
| <a href=#106 id=106 data-nosnippet>106</a> <span class="macro">bail!</span>( |
| <a href=#107 id=107 data-nosnippet>107</a> <span class="kw-2">*</span>loc, |
| <a href=#108 id=108 data-nosnippet>108</a> <span class="string">"The first element in a sequence of productions or alternatives \ |
| <a href=#109 id=109 data-nosnippet>109</a> must not have a leading pipe (`|`)" |
| <a href=#110 id=110 data-nosnippet>110</a> </span>); |
| <a href=#111 id=111 data-nosnippet>111</a> } |
| <a href=#112 id=112 data-nosnippet>112</a> |
| <a href=#113 id=113 data-nosnippet>113</a> <span class="kw">let </span>lhs = seq_rule(p)<span class="question-mark">?</span>; |
| <a href=#114 id=114 data-nosnippet>114</a> <span class="kw">let </span><span class="kw-2">mut </span>alt = <span class="macro">vec!</span>[lhs]; |
| <a href=#115 id=115 data-nosnippet>115</a> <span class="kw">while let </span><span class="prelude-val">Some</span>(token) = p.peek() { |
| <a href=#116 id=116 data-nosnippet>116</a> <span class="kw">if </span>token.<span class="macro">kind !</span>= TokenKind::Pipe { |
| <a href=#117 id=117 data-nosnippet>117</a> <span class="kw">break</span>; |
| <a href=#118 id=118 data-nosnippet>118</a> } |
| <a href=#119 id=119 data-nosnippet>119</a> p.bump()<span class="question-mark">?</span>; |
| <a href=#120 id=120 data-nosnippet>120</a> <span class="kw">let </span>rule = seq_rule(p)<span class="question-mark">?</span>; |
| <a href=#121 id=121 data-nosnippet>121</a> alt.push(rule) |
| <a href=#122 id=122 data-nosnippet>122</a> } |
| <a href=#123 id=123 data-nosnippet>123</a> <span class="kw">let </span>res = <span class="kw">if </span>alt.len() == <span class="number">1 </span>{ alt.pop().unwrap() } <span class="kw">else </span>{ Rule::Alt(alt) }; |
| <a href=#124 id=124 data-nosnippet>124</a> <span class="prelude-val">Ok</span>(res) |
| <a href=#125 id=125 data-nosnippet>125</a>} |
| <a href=#126 id=126 data-nosnippet>126</a> |
| <a href=#127 id=127 data-nosnippet>127</a><span class="kw">fn </span>seq_rule(p: <span class="kw-2">&mut </span>Parser) -> <span class="prelude-ty">Result</span><Rule> { |
| <a href=#128 id=128 data-nosnippet>128</a> <span class="kw">let </span>lhs = atom_rule(p)<span class="question-mark">?</span>; |
| <a href=#129 id=129 data-nosnippet>129</a> |
| <a href=#130 id=130 data-nosnippet>130</a> <span class="kw">let </span><span class="kw-2">mut </span>seq = <span class="macro">vec!</span>[lhs]; |
| <a href=#131 id=131 data-nosnippet>131</a> <span class="kw">while let </span><span class="prelude-val">Some</span>(rule) = opt_atom_rule(p)<span class="question-mark">? </span>{ |
| <a href=#132 id=132 data-nosnippet>132</a> seq.push(rule) |
| <a href=#133 id=133 data-nosnippet>133</a> } |
| <a href=#134 id=134 data-nosnippet>134</a> <span class="kw">let </span>res = <span class="kw">if </span>seq.len() == <span class="number">1 </span>{ seq.pop().unwrap() } <span class="kw">else </span>{ Rule::Seq(seq) }; |
| <a href=#135 id=135 data-nosnippet>135</a> <span class="prelude-val">Ok</span>(res) |
| <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="kw">fn </span>atom_rule(p: <span class="kw-2">&mut </span>Parser) -> <span class="prelude-ty">Result</span><Rule> { |
| <a href=#139 id=139 data-nosnippet>139</a> <span class="kw">match </span>opt_atom_rule(p)<span class="question-mark">? </span>{ |
| <a href=#140 id=140 data-nosnippet>140</a> <span class="prelude-val">Some</span>(it) => <span class="prelude-val">Ok</span>(it), |
| <a href=#141 id=141 data-nosnippet>141</a> <span class="prelude-val">None </span>=> { |
| <a href=#142 id=142 data-nosnippet>142</a> <span class="kw">let </span>token = p.bump()<span class="question-mark">?</span>; |
| <a href=#143 id=143 data-nosnippet>143</a> <span class="macro">bail!</span>(token.loc, <span class="string">"unexpected token"</span>) |
| <a href=#144 id=144 data-nosnippet>144</a> } |
| <a href=#145 id=145 data-nosnippet>145</a> } |
| <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">fn </span>opt_atom_rule(p: <span class="kw-2">&mut </span>Parser) -> <span class="prelude-ty">Result</span><<span class="prelude-ty">Option</span><Rule>> { |
| <a href=#149 id=149 data-nosnippet>149</a> <span class="kw">let </span>token = <span class="kw">match </span>p.peek() { |
| <a href=#150 id=150 data-nosnippet>150</a> <span class="prelude-val">Some</span>(it) => it, |
| <a href=#151 id=151 data-nosnippet>151</a> <span class="prelude-val">None </span>=> <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>), |
| <a href=#152 id=152 data-nosnippet>152</a> }; |
| <a href=#153 id=153 data-nosnippet>153</a> <span class="kw">let </span><span class="kw-2">mut </span>res = <span class="kw">match </span><span class="kw-2">&</span>token.kind { |
| <a href=#154 id=154 data-nosnippet>154</a> TokenKind::Node(name) => { |
| <a href=#155 id=155 data-nosnippet>155</a> <span class="kw">if let </span><span class="prelude-val">Some</span>(lookahead) = p.peek_n(<span class="number">1</span>) { |
| <a href=#156 id=156 data-nosnippet>156</a> <span class="kw">match </span>lookahead.kind { |
| <a href=#157 id=157 data-nosnippet>157</a> TokenKind::Eq => <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>), |
| <a href=#158 id=158 data-nosnippet>158</a> TokenKind::Colon => { |
| <a href=#159 id=159 data-nosnippet>159</a> <span class="kw">let </span>label = name.clone(); |
| <a href=#160 id=160 data-nosnippet>160</a> p.bump()<span class="question-mark">?</span>; |
| <a href=#161 id=161 data-nosnippet>161</a> p.bump()<span class="question-mark">?</span>; |
| <a href=#162 id=162 data-nosnippet>162</a> <span class="kw">let </span>rule = atom_rule(p)<span class="question-mark">?</span>; |
| <a href=#163 id=163 data-nosnippet>163</a> <span class="kw">let </span>res = Rule::Labeled { label, rule: Box::new(rule) }; |
| <a href=#164 id=164 data-nosnippet>164</a> <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="prelude-val">Some</span>(res)); |
| <a href=#165 id=165 data-nosnippet>165</a> } |
| <a href=#166 id=166 data-nosnippet>166</a> <span class="kw">_ </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> <span class="kw">match </span>p.peek_n(<span class="number">1</span>) { |
| <a href=#170 id=170 data-nosnippet>170</a> <span class="prelude-val">Some</span>(token) <span class="kw">if </span>token.kind == TokenKind::Eq => <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>), |
| <a href=#171 id=171 data-nosnippet>171</a> <span class="kw">_ </span>=> (), |
| <a href=#172 id=172 data-nosnippet>172</a> } |
| <a href=#173 id=173 data-nosnippet>173</a> <span class="kw">let </span>name = name.clone(); |
| <a href=#174 id=174 data-nosnippet>174</a> p.bump()<span class="question-mark">?</span>; |
| <a href=#175 id=175 data-nosnippet>175</a> <span class="kw">let </span>node = p.intern_node(name); |
| <a href=#176 id=176 data-nosnippet>176</a> Rule::Node(node) |
| <a href=#177 id=177 data-nosnippet>177</a> } |
| <a href=#178 id=178 data-nosnippet>178</a> TokenKind::Token(name) => { |
| <a href=#179 id=179 data-nosnippet>179</a> <span class="kw">let </span>name = name.clone(); |
| <a href=#180 id=180 data-nosnippet>180</a> p.bump()<span class="question-mark">?</span>; |
| <a href=#181 id=181 data-nosnippet>181</a> <span class="kw">let </span>token = p.intern_token(name); |
| <a href=#182 id=182 data-nosnippet>182</a> Rule::Token(token) |
| <a href=#183 id=183 data-nosnippet>183</a> } |
| <a href=#184 id=184 data-nosnippet>184</a> TokenKind::LParen => { |
| <a href=#185 id=185 data-nosnippet>185</a> p.bump()<span class="question-mark">?</span>; |
| <a href=#186 id=186 data-nosnippet>186</a> <span class="kw">let </span>rule = rule(p)<span class="question-mark">?</span>; |
| <a href=#187 id=187 data-nosnippet>187</a> p.expect(TokenKind::RParen, <span class="string">")"</span>)<span class="question-mark">?</span>; |
| <a href=#188 id=188 data-nosnippet>188</a> rule |
| <a href=#189 id=189 data-nosnippet>189</a> } |
| <a href=#190 id=190 data-nosnippet>190</a> <span class="kw">_ </span>=> <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>), |
| <a href=#191 id=191 data-nosnippet>191</a> }; |
| <a href=#192 id=192 data-nosnippet>192</a> |
| <a href=#193 id=193 data-nosnippet>193</a> <span class="kw">if let </span><span class="prelude-val">Some</span>(token) = p.peek() { |
| <a href=#194 id=194 data-nosnippet>194</a> <span class="kw">match </span><span class="kw-2">&</span>token.kind { |
| <a href=#195 id=195 data-nosnippet>195</a> TokenKind::QMark => { |
| <a href=#196 id=196 data-nosnippet>196</a> p.bump()<span class="question-mark">?</span>; |
| <a href=#197 id=197 data-nosnippet>197</a> res = Rule::Opt(Box::new(res)); |
| <a href=#198 id=198 data-nosnippet>198</a> } |
| <a href=#199 id=199 data-nosnippet>199</a> TokenKind::Star => { |
| <a href=#200 id=200 data-nosnippet>200</a> p.bump()<span class="question-mark">?</span>; |
| <a href=#201 id=201 data-nosnippet>201</a> res = Rule::Rep(Box::new(res)); |
| <a href=#202 id=202 data-nosnippet>202</a> } |
| <a href=#203 id=203 data-nosnippet>203</a> <span class="kw">_ </span>=> (), |
| <a href=#204 id=204 data-nosnippet>204</a> } |
| <a href=#205 id=205 data-nosnippet>205</a> } |
| <a href=#206 id=206 data-nosnippet>206</a> <span class="prelude-val">Ok</span>(<span class="prelude-val">Some</span>(res)) |
| <a href=#207 id=207 data-nosnippet>207</a>} |
| </code></pre></div></section></main></body></html> |
