<!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 `src/parser.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>parser.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button><a class="sidebar-logo" href="../../llvm_kaleidoscope_rs/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2 class="location"></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../../llvm_kaleidoscope_rs/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><div class="sub-container"><a class="sub-logo-container" href="../../llvm_kaleidoscope_rs/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><nav class="sub"><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><button type="button">?</button></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav></div><section id="main-content" class="content"><div class="example-wrap"><pre class="line-numbers"><span id="1">1</span>
<span id="2">2</span>
<span id="3">3</span>
<span id="4">4</span>
<span id="5">5</span>
<span id="6">6</span>
<span id="7">7</span>
<span id="8">8</span>
<span id="9">9</span>
<span id="10">10</span>
<span id="11">11</span>
<span id="12">12</span>
<span id="13">13</span>
<span id="14">14</span>
<span id="15">15</span>
<span id="16">16</span>
<span id="17">17</span>
<span id="18">18</span>
<span id="19">19</span>
<span id="20">20</span>
<span id="21">21</span>
<span id="22">22</span>
<span id="23">23</span>
<span id="24">24</span>
<span id="25">25</span>
<span id="26">26</span>
<span id="27">27</span>
<span id="28">28</span>
<span id="29">29</span>
<span id="30">30</span>
<span id="31">31</span>
<span id="32">32</span>
<span id="33">33</span>
<span id="34">34</span>
<span id="35">35</span>
<span id="36">36</span>
<span id="37">37</span>
<span id="38">38</span>
<span id="39">39</span>
<span id="40">40</span>
<span id="41">41</span>
<span id="42">42</span>
<span id="43">43</span>
<span id="44">44</span>
<span id="45">45</span>
<span id="46">46</span>
<span id="47">47</span>
<span id="48">48</span>
<span id="49">49</span>
<span id="50">50</span>
<span id="51">51</span>
<span id="52">52</span>
<span id="53">53</span>
<span id="54">54</span>
<span id="55">55</span>
<span id="56">56</span>
<span id="57">57</span>
<span id="58">58</span>
<span id="59">59</span>
<span id="60">60</span>
<span id="61">61</span>
<span id="62">62</span>
<span id="63">63</span>
<span id="64">64</span>
<span id="65">65</span>
<span id="66">66</span>
<span id="67">67</span>
<span id="68">68</span>
<span id="69">69</span>
<span id="70">70</span>
<span id="71">71</span>
<span id="72">72</span>
<span id="73">73</span>
<span id="74">74</span>
<span id="75">75</span>
<span id="76">76</span>
<span id="77">77</span>
<span id="78">78</span>
<span id="79">79</span>
<span id="80">80</span>
<span id="81">81</span>
<span id="82">82</span>
<span id="83">83</span>
<span id="84">84</span>
<span id="85">85</span>
<span id="86">86</span>
<span id="87">87</span>
<span id="88">88</span>
<span id="89">89</span>
<span id="90">90</span>
<span id="91">91</span>
<span id="92">92</span>
<span id="93">93</span>
<span id="94">94</span>
<span id="95">95</span>
<span id="96">96</span>
<span id="97">97</span>
<span id="98">98</span>
<span id="99">99</span>
<span id="100">100</span>
<span id="101">101</span>
<span id="102">102</span>
<span id="103">103</span>
<span id="104">104</span>
<span id="105">105</span>
<span id="106">106</span>
<span id="107">107</span>
<span id="108">108</span>
<span id="109">109</span>
<span id="110">110</span>
<span id="111">111</span>
<span id="112">112</span>
<span id="113">113</span>
<span id="114">114</span>
<span id="115">115</span>
<span id="116">116</span>
<span id="117">117</span>
<span id="118">118</span>
<span id="119">119</span>
<span id="120">120</span>
<span id="121">121</span>
<span id="122">122</span>
<span id="123">123</span>
<span id="124">124</span>
<span id="125">125</span>
<span id="126">126</span>
<span id="127">127</span>
<span id="128">128</span>
<span id="129">129</span>
<span id="130">130</span>
<span id="131">131</span>
<span id="132">132</span>
<span id="133">133</span>
<span id="134">134</span>
<span id="135">135</span>
<span id="136">136</span>
<span id="137">137</span>
<span id="138">138</span>
<span id="139">139</span>
<span id="140">140</span>
<span id="141">141</span>
<span id="142">142</span>
<span id="143">143</span>
<span id="144">144</span>
<span id="145">145</span>
<span id="146">146</span>
<span id="147">147</span>
<span id="148">148</span>
<span id="149">149</span>
<span id="150">150</span>
<span id="151">151</span>
<span id="152">152</span>
<span id="153">153</span>
<span id="154">154</span>
<span id="155">155</span>
<span id="156">156</span>
<span id="157">157</span>
<span id="158">158</span>
<span id="159">159</span>
<span id="160">160</span>
<span id="161">161</span>
<span id="162">162</span>
<span id="163">163</span>
<span id="164">164</span>
<span id="165">165</span>
<span id="166">166</span>
<span id="167">167</span>
<span id="168">168</span>
<span id="169">169</span>
<span id="170">170</span>
<span id="171">171</span>
<span id="172">172</span>
<span id="173">173</span>
<span id="174">174</span>
<span id="175">175</span>
<span id="176">176</span>
<span id="177">177</span>
<span id="178">178</span>
<span id="179">179</span>
<span id="180">180</span>
<span id="181">181</span>
<span id="182">182</span>
<span id="183">183</span>
<span id="184">184</span>
<span id="185">185</span>
<span id="186">186</span>
<span id="187">187</span>
<span id="188">188</span>
<span id="189">189</span>
<span id="190">190</span>
<span id="191">191</span>
<span id="192">192</span>
<span id="193">193</span>
<span id="194">194</span>
<span id="195">195</span>
<span id="196">196</span>
<span id="197">197</span>
<span id="198">198</span>
<span id="199">199</span>
<span id="200">200</span>
<span id="201">201</span>
<span id="202">202</span>
<span id="203">203</span>
<span id="204">204</span>
<span id="205">205</span>
<span id="206">206</span>
<span id="207">207</span>
<span id="208">208</span>
<span id="209">209</span>
<span id="210">210</span>
<span id="211">211</span>
<span id="212">212</span>
<span id="213">213</span>
<span id="214">214</span>
<span id="215">215</span>
<span id="216">216</span>
<span id="217">217</span>
<span id="218">218</span>
<span id="219">219</span>
<span id="220">220</span>
<span id="221">221</span>
<span id="222">222</span>
<span id="223">223</span>
<span id="224">224</span>
<span id="225">225</span>
<span id="226">226</span>
<span id="227">227</span>
<span id="228">228</span>
<span id="229">229</span>
<span id="230">230</span>
<span id="231">231</span>
<span id="232">232</span>
<span id="233">233</span>
<span id="234">234</span>
<span id="235">235</span>
<span id="236">236</span>
<span id="237">237</span>
<span id="238">238</span>
<span id="239">239</span>
<span id="240">240</span>
<span id="241">241</span>
<span id="242">242</span>
<span id="243">243</span>
<span id="244">244</span>
<span id="245">245</span>
<span id="246">246</span>
<span id="247">247</span>
<span id="248">248</span>
<span id="249">249</span>
<span id="250">250</span>
<span id="251">251</span>
<span id="252">252</span>
<span id="253">253</span>
<span id="254">254</span>
<span id="255">255</span>
<span id="256">256</span>
<span id="257">257</span>
<span id="258">258</span>
<span id="259">259</span>
<span id="260">260</span>
<span id="261">261</span>
<span id="262">262</span>
<span id="263">263</span>
<span id="264">264</span>
<span id="265">265</span>
<span id="266">266</span>
<span id="267">267</span>
<span id="268">268</span>
<span id="269">269</span>
<span id="270">270</span>
<span id="271">271</span>
<span id="272">272</span>
<span id="273">273</span>
<span id="274">274</span>
<span id="275">275</span>
<span id="276">276</span>
<span id="277">277</span>
<span id="278">278</span>
<span id="279">279</span>
<span id="280">280</span>
<span id="281">281</span>
<span id="282">282</span>
<span id="283">283</span>
<span id="284">284</span>
<span id="285">285</span>
<span id="286">286</span>
<span id="287">287</span>
<span id="288">288</span>
<span id="289">289</span>
<span id="290">290</span>
<span id="291">291</span>
<span id="292">292</span>
<span id="293">293</span>
<span id="294">294</span>
<span id="295">295</span>
<span id="296">296</span>
<span id="297">297</span>
<span id="298">298</span>
<span id="299">299</span>
<span id="300">300</span>
<span id="301">301</span>
<span id="302">302</span>
<span id="303">303</span>
<span id="304">304</span>
<span id="305">305</span>
<span id="306">306</span>
<span id="307">307</span>
<span id="308">308</span>
<span id="309">309</span>
<span id="310">310</span>
<span id="311">311</span>
<span id="312">312</span>
<span id="313">313</span>
<span id="314">314</span>
<span id="315">315</span>
<span id="316">316</span>
<span id="317">317</span>
<span id="318">318</span>
<span id="319">319</span>
<span id="320">320</span>
<span id="321">321</span>
<span id="322">322</span>
<span id="323">323</span>
<span id="324">324</span>
<span id="325">325</span>
<span id="326">326</span>
<span id="327">327</span>
<span id="328">328</span>
<span id="329">329</span>
<span id="330">330</span>
<span id="331">331</span>
<span id="332">332</span>
<span id="333">333</span>
<span id="334">334</span>
<span id="335">335</span>
<span id="336">336</span>
<span id="337">337</span>
<span id="338">338</span>
<span id="339">339</span>
<span id="340">340</span>
<span id="341">341</span>
<span id="342">342</span>
<span id="343">343</span>
<span id="344">344</span>
<span id="345">345</span>
<span id="346">346</span>
<span id="347">347</span>
<span id="348">348</span>
<span id="349">349</span>
<span id="350">350</span>
<span id="351">351</span>
<span id="352">352</span>
<span id="353">353</span>
<span id="354">354</span>
<span id="355">355</span>
<span id="356">356</span>
<span id="357">357</span>
<span id="358">358</span>
<span id="359">359</span>
<span id="360">360</span>
<span id="361">361</span>
<span id="362">362</span>
<span id="363">363</span>
<span id="364">364</span>
<span id="365">365</span>
<span id="366">366</span>
<span id="367">367</span>
<span id="368">368</span>
<span id="369">369</span>
<span id="370">370</span>
<span id="371">371</span>
<span id="372">372</span>
<span id="373">373</span>
<span id="374">374</span>
<span id="375">375</span>
<span id="376">376</span>
<span id="377">377</span>
<span id="378">378</span>
<span id="379">379</span>
<span id="380">380</span>
<span id="381">381</span>
<span id="382">382</span>
<span id="383">383</span>
<span id="384">384</span>
<span id="385">385</span>
<span id="386">386</span>
<span id="387">387</span>
<span id="388">388</span>
<span id="389">389</span>
<span id="390">390</span>
<span id="391">391</span>
<span id="392">392</span>
<span id="393">393</span>
<span id="394">394</span>
<span id="395">395</span>
<span id="396">396</span>
<span id="397">397</span>
<span id="398">398</span>
<span id="399">399</span>
<span id="400">400</span>
<span id="401">401</span>
<span id="402">402</span>
<span id="403">403</span>
<span id="404">404</span>
<span id="405">405</span>
<span id="406">406</span>
<span id="407">407</span>
<span id="408">408</span>
<span id="409">409</span>
<span id="410">410</span>
<span id="411">411</span>
<span id="412">412</span>
<span id="413">413</span>
<span id="414">414</span>
<span id="415">415</span>
<span id="416">416</span>
<span id="417">417</span>
<span id="418">418</span>
<span id="419">419</span>
<span id="420">420</span>
<span id="421">421</span>
<span id="422">422</span>
<span id="423">423</span>
<span id="424">424</span>
<span id="425">425</span>
<span id="426">426</span>
<span id="427">427</span>
<span id="428">428</span>
<span id="429">429</span>
<span id="430">430</span>
<span id="431">431</span>
<span id="432">432</span>
<span id="433">433</span>
<span id="434">434</span>
<span id="435">435</span>
<span id="436">436</span>
<span id="437">437</span>
<span id="438">438</span>
<span id="439">439</span>
<span id="440">440</span>
<span id="441">441</span>
<span id="442">442</span>
<span id="443">443</span>
<span id="444">444</span>
<span id="445">445</span>
<span id="446">446</span>
<span id="447">447</span>
<span id="448">448</span>
<span id="449">449</span>
<span id="450">450</span>
<span id="451">451</span>
<span id="452">452</span>
<span id="453">453</span>
<span id="454">454</span>
<span id="455">455</span>
<span id="456">456</span>
<span id="457">457</span>
<span id="458">458</span>
<span id="459">459</span>
<span id="460">460</span>
<span id="461">461</span>
<span id="462">462</span>
<span id="463">463</span>
<span id="464">464</span>
<span id="465">465</span>
<span id="466">466</span>
<span id="467">467</span>
<span id="468">468</span>
<span id="469">469</span>
<span id="470">470</span>
<span id="471">471</span>
<span id="472">472</span>
<span id="473">473</span>
<span id="474">474</span>
<span id="475">475</span>
<span id="476">476</span>
<span id="477">477</span>
<span id="478">478</span>
<span id="479">479</span>
<span id="480">480</span>
<span id="481">481</span>
<span id="482">482</span>
<span id="483">483</span>
<span id="484">484</span>
<span id="485">485</span>
<span id="486">486</span>
<span id="487">487</span>
<span id="488">488</span>
<span id="489">489</span>
<span id="490">490</span>
<span id="491">491</span>
<span id="492">492</span>
<span id="493">493</span>
<span id="494">494</span>
<span id="495">495</span>
<span id="496">496</span>
<span id="497">497</span>
<span id="498">498</span>
<span id="499">499</span>
<span id="500">500</span>
<span id="501">501</span>
<span id="502">502</span>
<span id="503">503</span>
<span id="504">504</span>
<span id="505">505</span>
<span id="506">506</span>
<span id="507">507</span>
<span id="508">508</span>
<span id="509">509</span>
<span id="510">510</span>
<span id="511">511</span>
<span id="512">512</span>
<span id="513">513</span>
<span id="514">514</span>
<span id="515">515</span>
<span id="516">516</span>
<span id="517">517</span>
<span id="518">518</span>
<span id="519">519</span>
<span id="520">520</span>
<span id="521">521</span>
<span id="522">522</span>
<span id="523">523</span>
<span id="524">524</span>
<span id="525">525</span>
<span id="526">526</span>
<span id="527">527</span>
<span id="528">528</span>
<span id="529">529</span>
<span id="530">530</span>
<span id="531">531</span>
<span id="532">532</span>
<span id="533">533</span>
<span id="534">534</span>
<span id="535">535</span>
<span id="536">536</span>
<span id="537">537</span>
<span id="538">538</span>
<span id="539">539</span>
<span id="540">540</span>
<span id="541">541</span>
<span id="542">542</span>
<span id="543">543</span>
<span id="544">544</span>
<span id="545">545</span>
<span id="546">546</span>
<span id="547">547</span>
<span id="548">548</span>
<span id="549">549</span>
<span id="550">550</span>
<span id="551">551</span>
<span id="552">552</span>
<span id="553">553</span>
<span id="554">554</span>
<span id="555">555</span>
<span id="556">556</span>
<span id="557">557</span>
<span id="558">558</span>
<span id="559">559</span>
<span id="560">560</span>
<span id="561">561</span>
<span id="562">562</span>
<span id="563">563</span>
<span id="564">564</span>
<span id="565">565</span>
<span id="566">566</span>
<span id="567">567</span>
<span id="568">568</span>
<span id="569">569</span>
<span id="570">570</span>
<span id="571">571</span>
<span id="572">572</span>
<span id="573">573</span>
<span id="574">574</span>
<span id="575">575</span>
<span id="576">576</span>
<span id="577">577</span>
<span id="578">578</span>
<span id="579">579</span>
<span id="580">580</span>
<span id="581">581</span>
<span id="582">582</span>
<span id="583">583</span>
<span id="584">584</span>
<span id="585">585</span>
<span id="586">586</span>
<span id="587">587</span>
<span id="588">588</span>
<span id="589">589</span>
<span id="590">590</span>
<span id="591">591</span>
<span id="592">592</span>
<span id="593">593</span>
<span id="594">594</span>
<span id="595">595</span>
<span id="596">596</span>
<span id="597">597</span>
<span id="598">598</span>
<span id="599">599</span>
<span id="600">600</span>
<span id="601">601</span>
<span id="602">602</span>
<span id="603">603</span>
<span id="604">604</span>
<span id="605">605</span>
<span id="606">606</span>
<span id="607">607</span>
<span id="608">608</span>
<span id="609">609</span>
<span id="610">610</span>
<span id="611">611</span>
<span id="612">612</span>
<span id="613">613</span>
<span id="614">614</span>
<span id="615">615</span>
<span id="616">616</span>
<span id="617">617</span>
<span id="618">618</span>
<span id="619">619</span>
<span id="620">620</span>
<span id="621">621</span>
<span id="622">622</span>
<span id="623">623</span>
<span id="624">624</span>
<span id="625">625</span>
<span id="626">626</span>
<span id="627">627</span>
<span id="628">628</span>
<span id="629">629</span>
<span id="630">630</span>
<span id="631">631</span>
<span id="632">632</span>
<span id="633">633</span>
<span id="634">634</span>
<span id="635">635</span>
<span id="636">636</span>
<span id="637">637</span>
<span id="638">638</span>
<span id="639">639</span>
<span id="640">640</span>
<span id="641">641</span>
<span id="642">642</span>
<span id="643">643</span>
<span id="644">644</span>
<span id="645">645</span>
<span id="646">646</span>
<span id="647">647</span>
<span id="648">648</span>
<span id="649">649</span>
<span id="650">650</span>
<span id="651">651</span>
<span id="652">652</span>
<span id="653">653</span>
<span id="654">654</span>
</pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::lexer::{Lexer, Token};
<span class="attribute">#[derive(Debug, PartialEq)]
</span><span class="kw">pub enum </span>ExprAST {
<span class="doccomment">/// Number - Expression class for numeric literals like "1.0".
</span>Number(f64),
<span class="doccomment">/// Variable - Expression class for referencing a variable, like "a".
</span>Variable(String),
<span class="doccomment">/// Binary - Expression class for a binary operator.
</span>Binary(char, Box<ExprAST>, Box<ExprAST>),
<span class="doccomment">/// Call - Expression class for function calls.
</span>Call(String, Vec<ExprAST>),
<span class="doccomment">/// If - Expression class for if/then/else.
</span>If {
cond: Box<ExprAST>,
then: Box<ExprAST>,
else_: Box<ExprAST>,
},
<span class="doccomment">/// ForExprAST - Expression class for for/in.
</span>For {
var: String,
start: Box<ExprAST>,
end: Box<ExprAST>,
step: <span class="prelude-ty">Option</span><Box<ExprAST>>,
body: Box<ExprAST>,
},
}
<span class="doccomment">/// PrototypeAST - This class represents the "prototype" for a function,
/// which captures its name, and its argument names (thus implicitly the number
/// of arguments the function takes).
</span><span class="attribute">#[derive(Debug, PartialEq, Clone)]
</span><span class="kw">pub struct </span>PrototypeAST(<span class="kw">pub </span>String, <span class="kw">pub </span>Vec<String>);
<span class="doccomment">/// FunctionAST - This class represents a function definition itself.
</span><span class="attribute">#[derive(Debug, PartialEq)]
</span><span class="kw">pub struct </span>FunctionAST(<span class="kw">pub </span>PrototypeAST, <span class="kw">pub </span>ExprAST);
<span class="doccomment">/// Parse result with String as Error type (to be compliant with tutorial).
</span><span class="kw">type </span>ParseResult<T> = <span class="prelude-ty">Result</span><T, String>;
<span class="doccomment">/// Parser for the `kaleidoscope` language.
</span><span class="kw">pub struct </span>Parser<I>
<span class="kw">where
</span>I: Iterator<Item = char>,
{
lexer: Lexer<I>,
cur_tok: <span class="prelude-ty">Option</span><Token>,
}
<span class="kw">impl</span><I> Parser<I>
<span class="kw">where
</span>I: Iterator<Item = char>,
{
<span class="kw">pub fn </span>new(lexer: Lexer<I>) -> <span class="self">Self </span>{
Parser {
lexer,
cur_tok: <span class="prelude-val">None</span>,
}
}
<span class="comment">// -----------------------
// Simple Token Buffer
// -----------------------
</span><span class="doccomment">/// Implement the global variable `int CurTok;` from the tutorial.
///
/// # Panics
/// Panics if the parser doesn't have a current token.
</span><span class="kw">pub fn </span>cur_tok(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>Token {
<span class="self">self</span>.cur_tok.as_ref().expect(<span class="string">"Parser: Expected cur_token!"</span>)
}
<span class="doccomment">/// Advance the `cur_tok` by getting the next token from the lexer.
///
/// Implement the fucntion `int getNextToken();` from the tutorial.
</span><span class="kw">pub fn </span>get_next_token(<span class="kw-2">&mut </span><span class="self">self</span>) {
<span class="self">self</span>.cur_tok = <span class="prelude-val">Some</span>(<span class="self">self</span>.lexer.gettok());
}
<span class="comment">// ----------------------------
// Basic Expression Parsing
// ----------------------------
</span><span class="doccomment">/// numberexpr ::= number
///
/// Implement `std::unique_ptr<ExprAST> ParseNumberExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_num_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="kw">match </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() {
Token::Number(num) => {
<span class="comment">// Consume the number token.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Ok</span>(ExprAST::Number(num))
}
<span class="kw">_ </span>=> <span class="macro">unreachable!</span>(),
}
}
<span class="doccomment">/// parenexpr ::= '(' expression ')'
///
/// Implement `std::unique_ptr<ExprAST> ParseParenExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_paren_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="comment">// Eat '(' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::Char(<span class="string">'('</span>));
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>v = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() == Token::Char(<span class="string">')'</span>) {
<span class="comment">// Eat ')' token.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Ok</span>(v)
} <span class="kw">else </span>{
<span class="prelude-val">Err</span>(<span class="string">"expected ')'"</span>.into())
}
}
<span class="doccomment">/// identifierexpr
/// ::= identifier
/// ::= identifier '(' expression* ')'
///
/// Implement `std::unique_ptr<ExprAST> ParseIdentifierExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_identifier_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="kw">let </span>id_name = <span class="kw">match </span><span class="self">self</span>.cur_tok.take() {
<span class="prelude-val">Some</span>(Token::Identifier(id)) => {
<span class="comment">// Consume identifier.
</span><span class="self">self</span>.get_next_token();
id
}
<span class="kw">_ </span>=> <span class="macro">unreachable!</span>(),
};
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">'('</span>) {
<span class="comment">// Simple variable reference.
</span><span class="prelude-val">Ok</span>(ExprAST::Variable(id_name))
} <span class="kw">else </span>{
<span class="comment">// Call.
// Eat '(' token.
</span><span class="self">self</span>.get_next_token();
<span class="kw">let </span><span class="kw-2">mut </span>args: Vec<ExprAST> = Vec::new();
<span class="comment">// If there are arguments collect them.
</span><span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">')'</span>) {
<span class="kw">loop </span>{
<span class="kw">let </span>arg = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
args.push(arg);
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() == Token::Char(<span class="string">')'</span>) {
<span class="kw">break</span>;
}
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">','</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected ')' or ',' in argument list"</span>.into());
}
<span class="self">self</span>.get_next_token();
}
}
<span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::Char(<span class="string">')'</span>));
<span class="comment">// Eat ')' token.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Ok</span>(ExprAST::Call(id_name, args))
}
}
<span class="doccomment">/// ifexpr ::= 'if' expression 'then' expression 'else' expression
///
/// Implement `std::unique_ptr<ExprAST> ParseIfExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_if_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="comment">// Consume 'if' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::If);
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>cond = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">if </span><span class="kw-2">*</span><span class="macro">dbg!</span>(<span class="self">self</span>.cur_tok()) != Token::Then {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected 'then'"</span>.into());
}
<span class="comment">// Consume 'then' token.
</span><span class="self">self</span>.get_next_token();
<span class="kw">let </span>then = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Else {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected 'else'"</span>.into());
}
<span class="comment">// Consume 'else' token.
</span><span class="self">self</span>.get_next_token();
<span class="kw">let </span>else_ = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(ExprAST::If {
cond: Box::new(cond),
then: Box::new(then),
else_: Box::new(else_),
})
}
<span class="doccomment">/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
///
/// Implement `std::unique_ptr<ExprAST> ParseForExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_for_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="comment">// Consume the 'for' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::For);
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>var = <span class="kw">match </span><span class="self">self
</span>.parse_identifier_expr()
.map_err(|<span class="kw">_</span>| String::from(<span class="string">"expected identifier after 'for'"</span>))<span class="question-mark">?
</span>{
ExprAST::Variable(var) => var,
<span class="kw">_ </span>=> <span class="macro">unreachable!</span>(),
};
<span class="comment">// Consume the '=' token.
</span><span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">'='</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"expected '=' after for"</span>.into());
}
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>start = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="comment">// Consume the ',' token.
</span><span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">','</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"expected ',' after for start value"</span>.into());
}
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>end = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">let </span>step = <span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() == Token::Char(<span class="string">','</span>) {
<span class="comment">// Consume the ',' token.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Some</span>(<span class="self">self</span>.parse_expression()<span class="question-mark">?</span>)
} <span class="kw">else </span>{
<span class="prelude-val">None
</span>};
<span class="comment">// Consume the 'in' token.
</span><span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::In {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"expected 'in' after for"</span>.into());
}
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>body = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(ExprAST::For {
var,
start: Box::new(start),
end: Box::new(end),
step: step.map(|s| Box::new(s)),
body: Box::new(body),
})
}
<span class="doccomment">/// primary
/// ::= identifierexpr
/// ::= numberexpr
/// ::= parenexpr
///
/// Implement `std::unique_ptr<ExprAST> ParsePrimary();` from the tutorial.
</span><span class="kw">fn </span>parse_primary(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="kw">match </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() {
Token::Identifier(<span class="kw">_</span>) => <span class="self">self</span>.parse_identifier_expr(),
Token::Number(<span class="kw">_</span>) => <span class="self">self</span>.parse_num_expr(),
Token::Char(<span class="string">'('</span>) => <span class="self">self</span>.parse_paren_expr(),
Token::If => <span class="self">self</span>.parse_if_expr(),
Token::For => <span class="self">self</span>.parse_for_expr(),
<span class="kw">_ </span>=> <span class="prelude-val">Err</span>(<span class="string">"unknown token when expecting an expression"</span>.into()),
}
}
<span class="comment">// -----------------------------
// Binary Expression Parsing
// -----------------------------
</span><span class="doccomment">/// /// expression
/// ::= primary binoprhs
///
/// Implement `std::unique_ptr<ExprAST> ParseExpression();` from the tutorial.
</span><span class="kw">fn </span>parse_expression(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="kw">let </span>lhs = <span class="self">self</span>.parse_primary()<span class="question-mark">?</span>;
<span class="self">self</span>.parse_bin_op_rhs(<span class="number">0</span>, lhs)
}
<span class="doccomment">/// binoprhs
/// ::= ('+' primary)*
///
/// Implement `std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec, std::unique_ptr<ExprAST> LHS);` from the tutorial.
</span><span class="kw">fn </span>parse_bin_op_rhs(<span class="kw-2">&mut </span><span class="self">self</span>, expr_prec: isize, <span class="kw-2">mut </span>lhs: ExprAST) -> ParseResult<ExprAST> {
<span class="kw">loop </span>{
<span class="kw">let </span>tok_prec = get_tok_precedence(<span class="self">self</span>.cur_tok());
<span class="comment">// Not a binary operator or precedence is too small.
</span><span class="kw">if </span>tok_prec < expr_prec {
<span class="kw">return </span><span class="prelude-val">Ok</span>(lhs);
}
<span class="kw">let </span>binop = <span class="kw">match </span><span class="self">self</span>.cur_tok.take() {
<span class="prelude-val">Some</span>(Token::Char(c)) => {
<span class="comment">// Eat binary operator.
</span><span class="self">self</span>.get_next_token();
c
}
<span class="kw">_ </span>=> <span class="macro">unreachable!</span>(),
};
<span class="comment">// lhs BINOP1 rhs BINOP2 remrhs
// ^^^^^^ ^^^^^^
// tok_prec next_prec
//
// In case BINOP1 has higher precedence, we are done here and can build a 'Binary' AST
// node between 'lhs' and 'rhs'.
//
// In case BINOP2 has higher precedence, we take 'rhs' as 'lhs' and recurse into the
// 'remrhs' expression first.
// Parse primary expression after binary operator.
</span><span class="kw">let </span><span class="kw-2">mut </span>rhs = <span class="self">self</span>.parse_primary()<span class="question-mark">?</span>;
<span class="kw">let </span>next_prec = get_tok_precedence(<span class="self">self</span>.cur_tok());
<span class="kw">if </span>tok_prec < next_prec {
<span class="comment">// BINOP2 has higher precedence thatn BINOP1, recurse into 'remhs'.
</span>rhs = <span class="self">self</span>.parse_bin_op_rhs(tok_prec + <span class="number">1</span>, rhs)<span class="question-mark">?
</span>}
lhs = ExprAST::Binary(binop, Box::new(lhs), Box::new(rhs));
}
}
<span class="comment">// --------------------
// Parsing the Rest
// --------------------
</span><span class="doccomment">/// prototype
/// ::= id '(' id* ')'
///
/// Implement `std::unique_ptr<PrototypeAST> ParsePrototype();` from the tutorial.
</span><span class="kw">fn </span>parse_prototype(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<PrototypeAST> {
<span class="kw">let </span>id_name = <span class="kw">match </span><span class="self">self</span>.cur_tok.take() {
<span class="prelude-val">Some</span>(Token::Identifier(id)) => {
<span class="comment">// Consume the identifier.
</span><span class="self">self</span>.get_next_token();
id
}
other => {
<span class="comment">// Plug back current token.
</span><span class="self">self</span>.cur_tok = other;
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected function name in prototype"</span>.into());
}
};
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">'('</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected '(' in prototype"</span>.into());
}
<span class="kw">let </span><span class="kw-2">mut </span>args: Vec<String> = Vec::new();
<span class="kw">loop </span>{
<span class="self">self</span>.get_next_token();
<span class="kw">match </span><span class="self">self</span>.cur_tok.take() {
<span class="prelude-val">Some</span>(Token::Identifier(arg)) => args.push(arg),
<span class="prelude-val">Some</span>(Token::Char(<span class="string">','</span>)) => {}
other => {
<span class="self">self</span>.cur_tok = other;
<span class="kw">break</span>;
}
}
}
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">')'</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected ')' in prototype"</span>.into());
}
<span class="comment">// Consume ')'.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Ok</span>(PrototypeAST(id_name, args))
}
<span class="doccomment">/// definition ::= 'def' prototype expression
///
/// Implement `std::unique_ptr<FunctionAST> ParseDefinition();` from the tutorial.
</span><span class="kw">pub fn </span>parse_definition(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<FunctionAST> {
<span class="comment">// Consume 'def' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::Def);
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>proto = <span class="self">self</span>.parse_prototype()<span class="question-mark">?</span>;
<span class="kw">let </span>expr = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(FunctionAST(proto, expr))
}
<span class="doccomment">/// external ::= 'extern' prototype
///
/// Implement `std::unique_ptr<PrototypeAST> ParseExtern();` from the tutorial.
</span><span class="kw">pub fn </span>parse_extern(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<PrototypeAST> {
<span class="comment">// Consume 'extern' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::Extern);
<span class="self">self</span>.get_next_token();
<span class="self">self</span>.parse_prototype()
}
<span class="doccomment">/// toplevelexpr ::= expression
///
/// Implement `std::unique_ptr<FunctionAST> ParseTopLevelExpr();` from the tutorial.
</span><span class="kw">pub fn </span>parse_top_level_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<FunctionAST> {
<span class="kw">let </span>e = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">let </span>proto = PrototypeAST(<span class="string">"__anon_expr"</span>.into(), Vec::new());
<span class="prelude-val">Ok</span>(FunctionAST(proto, e))
}
}
<span class="doccomment">/// Get the binary operator precedence.
///
/// Implement `int GetTokPrecedence();` from the tutorial.
</span><span class="kw">fn </span>get_tok_precedence(tok: <span class="kw-2">&</span>Token) -> isize {
<span class="kw">match </span>tok {
Token::Char(<span class="string">'<'</span>) => <span class="number">10</span>,
Token::Char(<span class="string">'+'</span>) => <span class="number">20</span>,
Token::Char(<span class="string">'-'</span>) => <span class="number">20</span>,
Token::Char(<span class="string">'*'</span>) => <span class="number">40</span>,
<span class="kw">_ </span>=> -<span class="number">1</span>,
}
}
<span class="attribute">#[cfg(test)]
</span><span class="kw">mod </span>test {
<span class="kw">use super</span>::{ExprAST, FunctionAST, Parser, PrototypeAST};
<span class="kw">use </span><span class="kw">crate</span>::lexer::Lexer;
<span class="kw">fn </span>parser(input: <span class="kw-2">&</span>str) -> Parser<std::str::Chars> {
<span class="kw">let </span>l = Lexer::new(input.chars());
<span class="kw">let </span><span class="kw-2">mut </span>p = Parser::new(l);
<span class="comment">// Drop initial coin, initialize cur_tok.
</span>p.get_next_token();
p
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_number() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"13.37"</span>);
<span class="macro">assert_eq!</span>(p.parse_num_expr(), <span class="prelude-val">Ok</span>(ExprAST::Number(<span class="number">13.37f64</span>)));
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_variable() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"foop"</span>);
<span class="macro">assert_eq!</span>(
p.parse_identifier_expr(),
<span class="prelude-val">Ok</span>(ExprAST::Variable(<span class="string">"foop"</span>.into()))
);
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_if() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"if 1 then 2 else 3"</span>);
<span class="kw">let </span>cond = Box::new(ExprAST::Number(<span class="number">1f64</span>));
<span class="kw">let </span>then = Box::new(ExprAST::Number(<span class="number">2f64</span>));
<span class="kw">let </span>else_ = Box::new(ExprAST::Number(<span class="number">3f64</span>));
<span class="macro">assert_eq!</span>(p.parse_if_expr(), <span class="prelude-val">Ok</span>(ExprAST::If { cond, then, else_ }));
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"if foo() then bar(2) else baz(3)"</span>);
<span class="kw">let </span>cond = Box::new(ExprAST::Call(<span class="string">"foo"</span>.into(), <span class="macro">vec!</span>[]));
<span class="kw">let </span>then = Box::new(ExprAST::Call(<span class="string">"bar"</span>.into(), <span class="macro">vec!</span>[ExprAST::Number(<span class="number">2f64</span>)]));
<span class="kw">let </span>else_ = Box::new(ExprAST::Call(<span class="string">"baz"</span>.into(), <span class="macro">vec!</span>[ExprAST::Number(<span class="number">3f64</span>)]));
<span class="macro">assert_eq!</span>(p.parse_if_expr(), <span class="prelude-val">Ok</span>(ExprAST::If { cond, then, else_ }));
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_for() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"for i = 1, 2, 3 in 4"</span>);
<span class="kw">let </span>var = String::from(<span class="string">"i"</span>);
<span class="kw">let </span>start = Box::new(ExprAST::Number(<span class="number">1f64</span>));
<span class="kw">let </span>end = Box::new(ExprAST::Number(<span class="number">2f64</span>));
<span class="kw">let </span>step = <span class="prelude-val">Some</span>(Box::new(ExprAST::Number(<span class="number">3f64</span>)));
<span class="kw">let </span>body = Box::new(ExprAST::Number(<span class="number">4f64</span>));
<span class="macro">assert_eq!</span>(
p.parse_for_expr(),
<span class="prelude-val">Ok</span>(ExprAST::For {
var,
start,
end,
step,
body
})
);
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_for_no_step() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"for i = 1, 2 in 4"</span>);
<span class="kw">let </span>var = String::from(<span class="string">"i"</span>);
<span class="kw">let </span>start = Box::new(ExprAST::Number(<span class="number">1f64</span>));
<span class="kw">let </span>end = Box::new(ExprAST::Number(<span class="number">2f64</span>));
<span class="kw">let </span>step = <span class="prelude-val">None</span>;
<span class="kw">let </span>body = Box::new(ExprAST::Number(<span class="number">4f64</span>));
<span class="macro">assert_eq!</span>(
p.parse_for_expr(),
<span class="prelude-val">Ok</span>(ExprAST::For {
var,
start,
end,
step,
body
})
);
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_primary() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"1337 foop \n bla(123) \n if a then b else c \n for x=1,2 in 3"</span>);
<span class="macro">assert_eq!</span>(p.parse_primary(), <span class="prelude-val">Ok</span>(ExprAST::Number(<span class="number">1337f64</span>)));
<span class="macro">assert_eq!</span>(p.parse_primary(), <span class="prelude-val">Ok</span>(ExprAST::Variable(<span class="string">"foop"</span>.into())));
<span class="macro">assert_eq!</span>(
p.parse_primary(),
<span class="prelude-val">Ok</span>(ExprAST::Call(<span class="string">"bla"</span>.into(), <span class="macro">vec!</span>[ExprAST::Number(<span class="number">123f64</span>)]))
);
<span class="macro">assert_eq!</span>(
p.parse_primary(),
<span class="prelude-val">Ok</span>(ExprAST::If {
cond: Box::new(ExprAST::Variable(<span class="string">"a"</span>.into())),
then: Box::new(ExprAST::Variable(<span class="string">"b"</span>.into())),
else_: Box::new(ExprAST::Variable(<span class="string">"c"</span>.into())),
})
);
<span class="macro">assert_eq!</span>(
p.parse_primary(),
<span class="prelude-val">Ok</span>(ExprAST::For {
var: String::from(<span class="string">"x"</span>),
start: Box::new(ExprAST::Number(<span class="number">1f64</span>)),
end: Box::new(ExprAST::Number(<span class="number">2f64</span>)),
step: <span class="prelude-val">None</span>,
body: Box::new(ExprAST::Number(<span class="number">3f64</span>)),
})
);
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_binary_op() {
<span class="comment">// Operator before RHS has higher precedence, expected AST
//
// -
// / \
// + c
// / \
// a b
</span><span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"a + b - c"</span>);
<span class="kw">let </span>binexpr_ab = ExprAST::Binary(
<span class="string">'+'</span>,
Box::new(ExprAST::Variable(<span class="string">"a"</span>.into())),
Box::new(ExprAST::Variable(<span class="string">"b"</span>.into())),
);
<span class="kw">let </span>binexpr_abc = ExprAST::Binary(
<span class="string">'-'</span>,
Box::new(binexpr_ab),
Box::new(ExprAST::Variable(<span class="string">"c"</span>.into())),
);
<span class="macro">assert_eq!</span>(p.parse_expression(), <span class="prelude-val">Ok</span>(binexpr_abc));
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_binary_op2() {
<span class="comment">// Operator after RHS has higher precedence, expected AST
//
// +
// / \
// a *
// / \
// b c
</span><span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"a + b * c"</span>);
<span class="kw">let </span>binexpr_bc = ExprAST::Binary(
<span class="string">'*'</span>,
Box::new(ExprAST::Variable(<span class="string">"b"</span>.into())),
Box::new(ExprAST::Variable(<span class="string">"c"</span>.into())),
);
<span class="kw">let </span>binexpr_abc = ExprAST::Binary(
<span class="string">'+'</span>,
Box::new(ExprAST::Variable(<span class="string">"a"</span>.into())),
Box::new(binexpr_bc),
);
<span class="macro">assert_eq!</span>(p.parse_expression(), <span class="prelude-val">Ok</span>(binexpr_abc));
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_prototype() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"foo(a,b)"</span>);
<span class="kw">let </span>proto = PrototypeAST(<span class="string">"foo"</span>.into(), <span class="macro">vec!</span>[<span class="string">"a"</span>.into(), <span class="string">"b"</span>.into()]);
<span class="macro">assert_eq!</span>(p.parse_prototype(), <span class="prelude-val">Ok</span>(proto));
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_definition() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"def bar( arg0 , arg1 ) arg0 + arg1"</span>);
<span class="kw">let </span>proto = PrototypeAST(<span class="string">"bar"</span>.into(), <span class="macro">vec!</span>[<span class="string">"arg0"</span>.into(), <span class="string">"arg1"</span>.into()]);
<span class="kw">let </span>body = ExprAST::Binary(
<span class="string">'+'</span>,
Box::new(ExprAST::Variable(<span class="string">"arg0"</span>.into())),
Box::new(ExprAST::Variable(<span class="string">"arg1"</span>.into())),
);
<span class="kw">let </span>func = FunctionAST(proto, body);
<span class="macro">assert_eq!</span>(p.parse_definition(), <span class="prelude-val">Ok</span>(func));
}
<span class="attribute">#[test]
</span><span class="kw">fn </span>parse_extern() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"extern baz()"</span>);
<span class="kw">let </span>proto = PrototypeAST(<span class="string">"baz"</span>.into(), <span class="macro">vec!</span>[]);
<span class="macro">assert_eq!</span>(p.parse_extern(), <span class="prelude-val">Ok</span>(proto));
}
}
</code></pre></div>
</section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="llvm_kaleidoscope_rs" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.65.0 (897e37553 2022-11-02)" ></div></body></html>
