about summary refs log blame commit diff stats
path: root/html/011load.cc.html
blob: 0d20873990abc5672e00594bda6f2c8620dc0c33 (plain) (tree)
1
2
3
4
5
6
7
8
9
10



                                                                                          
                              

                                                
                                  

                                                                                         

                       
                                                                                                 
                                                                                            

                                      
                                
                             
                             
                            

                              
                                  
                                                                           
                               

        





                               

       
                         
                                                                                                   


                                                                 
 
                                                                                                                                            
                                                       
                                        
                                                                                                                 

                                                            

                                                                                  

                                      
                                                                                                                                             




                                                                                                                
                                                                                                                                                 
                                                           
                                                                     
                                                                                                                                                                                
                                                                                                   
                                                                                                                                                                                                                     
                                                                                                 



                                                                                                                                                                                  
                                                    
                                                                                                                                                                                                                                                           

                                                                                                                                                                                                                                                             
                                    
                                                                                                                                                                                                                                                                                              
                                                                                                  

                                                                                                                                                                                                                                                             
                                                                                                   

                                                        

                                                                                                                                                                                                      




                                                                               

                                                                                     
                                                                                                                                                            

                                                                                                                           




                                                                                                                                                                                                                   
                                                      
                                                                                                    
                                                        

                                                                                                                                                                                           
                                                                                                                                                                                                                                                                                                                                                             
                                                                                                                                                                                                                                        
                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                                                                                                                                                        
                                                                                                                                                                                                                                                                                                            

                                                                                                                                                                                                                                                                                                      
                                                                                                                                                                                                                                             
                                  
                                                                                                                      
                                                         
                                                                                                                                                                                                                                                                                 
                                                                                                                                                                                                      

                                
                                                                                                                                                                                                              
                                                           
                                                                                                    
                                                                                                                                                                                                            
                                                                                                                                                                                                                                                               
                                                                                                                                                                    
                                                  
                                                                                                                                                                                                                                  
                                                                                                                                                 
                                                                                
                                                                                                                                                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                                                            
                                  

                                
                                                                                                                                                                                                                   
                                                                                 
                                                                                                 
                                                                                                                                                                              
                                                                                                                                                                                                              

                                                                                                              

                                                            
                                                                                                                                                                                                                                                                                                                                        
                                                                                                      
                                                                                                                                                                                
                                                                                                                                                                                                                

                                                                                                                
                                                                                              




                                                                                                                                                                                                                
                                                                                                                       
                                                                                                      
                                  
                                                                                                 
                                                                                                                                                                                                                                                                                                                                                                                                              
                                                                                                                                                             
 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
                                                                                                                         
                                                                                                                                                                                           
                                                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                
                                                                                                                                                                                                                


                                                                                                                


                                                                                                                 
                                                                                                                                                                                                                                                                                                                                                                                                                                                           
                                                                                                                                                                                                 
                                                                                                                                                                                                          


                                                                                   

                                                                                                                                                                                                                    

                                                                                                              
                                                                                                                                                                           
                                                                                 
 
                                                                                                                                                                                         
                                                                                                                                                                                                           
 

                                                                                                                                                                                                                                                                                                                                                                                                                                                      
                                                                                                                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                                                                                                                                 
                                                                                                                                                                                                                                                                                                                                                                                              
                                                                                                                                                                                                                                                                                                                                                                                              

                                                                                                                                                                                                      


                                                                                                              

                                
                                                                                        
                                                                                                                                
                                                                                                    

                                                             
                                                                                                                   
                                                                                                                 








                                                                                                                                                                                                                                                                                               

                                

                                                                
                                                                                                                                                                                                      
                                      


                                                                                                                                                                                                                                                                                                                                                                                               



                                                                          

                                                                                                                                                                                                                                                                                                                                                                                                                                                                               






                                                                                                                 






                                                                                                                                                                                                                                                                                                                                                                              


                                  
                                                                                                            







                                                                                                                                                                                                                                                                                                                                                                              


                                  

                                                                                                                                                                                                                                                                                                                                    
                                                                           
                                                                                                                                                                                                                                                                                                                                                                                 


                                  
                                                                
                                           





                                                                                                                 

                                                                                                                  
                                      
 
                                                                     
                                        
                                                                                                                 

                                                            

                                                                                  

                                                                            
                                        
                                        
                                                                                                                 

                                                            

                                                                                  
 
                                                                              
                                        
                                        
                                                                                                                 


                                                            

                                                                                  
 
                                                                              
                                        
                                                                                                                 
                                        
                                                                                                                 

                                                            

                                                                                  
                                                            

                                                                                  

                                                                          
                                        
                                                                                                                                                         

                                                            

                                                                                  

                                                      
                                        




                                                                      
                                        




                                                                    
                                        
                                                                                                                             

                                                            

                                                                                                                                      

                                                                  
                                        
                                                                                                                                                                                        

                                                            


                                                                                  

                                                                     
                                        
                                                                                                                                                                                                                                                               

                                                            



                                                                                  

                                                               
                                        
                                                                                                                                                                                                                                                                       

                                                            



                                                                                                   

                                                           
                                        
                                                                                                                                
 
                                                                                                                           


                                                                             
                                                                                                                                       






                                                                                                                                                           



















                                                                                                                                                                                                                                   

                                                                    
                                        

                                                                                                                 
                                        

                                                                                                                 
                                                                 
 
                                                                             
                                        

                                                                                                                 
                                         

                                                                                                                 

                                                               










                                                                                                                                                                    


       
                                     
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Mu - 011load.cc</title>
<meta name="Generator" content="Vim/7.4">
<meta name="plugin-version" content="vim7.4_v2">
<meta name="syntax" content="cpp">
<meta name="settings" content="use_css,pre_wrap,no_foldcolumn,expand_tabs,prevent_copy=">
<meta name="colorscheme" content="minimal">
<style type="text/css">
<!--
pre { white-space: pre-wrap; font-family: monospace; color: #eeeeee; background-color: #080808; }
body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color: #080808; }
* { font-size: 12pt; font-size: 1em; }
.Constant { color: #00a0a0; }
.traceAbsent { color: #c00000; }
.cSpecial { color: #008000; }
.muRecipe { color: #ff8700; }
.Comment { color: #9090ff; }
.Delimiter { color: #800080; }
.Special { color: #c00000; }
.traceContains { color: #008000; }
.Normal { color: #eeeeee; background-color: #080808; padding-bottom: 1px; }
.Identifier { color: #ecf32c; }
-->
</style>

<script type='text/javascript'>
<!--

-->
</script>
</head>
<body>
<pre id='vimCodeElement'>
<span class="Comment">//: Phase 1 of running mu code: load it from a textual representation.</span>
<span class="Comment">//:</span>
<span class="Comment">//: The process of running mu code:</span>
<span class="Comment">//:   load -&gt; transform -&gt; run</span>

<span class="Delimiter">:(scenarios load)</span>  <span class="Comment">// use 'load' instead of 'run' in all scenarios in this layer</span>
<span class="Delimiter">:(scenario first_recipe)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>

<span class="Delimiter">:(code)</span>
vector&lt;recipe_ordinal&gt; load<span class="Delimiter">(</span>string form<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  istringstream in<span class="Delimiter">(</span>form<span class="Delimiter">);</span>
  in &gt;&gt; std::noskipws<span class="Delimiter">;</span>
  <span class="Identifier">return</span> load<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
<span class="Delimiter">}</span>

vector&lt;recipe_ordinal&gt; load<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  in &gt;&gt; std::noskipws<span class="Delimiter">;</span>
  vector&lt;recipe_ordinal&gt; result<span class="Delimiter">;</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
    skip_whitespace_and_comments<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
    string command = next_word<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>command<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Delimiter">{</span>
      assert<span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">));</span>
      <span class="Identifier">break</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    <span class="Comment">// Command Handlers</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>command == <span class="Constant">&quot;recipe&quot;</span> || command == <span class="Constant">&quot;def&quot;</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      recipe_ordinal r = slurp_recipe<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
      <span class="Normal">if</span> <span class="Delimiter">(</span>r &gt; <span class="Constant">0</span><span class="Delimiter">)</span> result<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>r<span class="Delimiter">);</span>
    <span class="Delimiter">}</span>
    <span class="Normal">else</span> <span class="Normal">if</span> <span class="Delimiter">(</span>command == <span class="Constant">&quot;recipe!&quot;</span> || command == <span class="Constant">&quot;def!&quot;</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
      Disable_redefine_checks = <span class="Constant">true</span><span class="Delimiter">;</span>
      recipe_ordinal r = slurp_recipe<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
      <span class="Normal">if</span> <span class="Delimiter">(</span>r &gt; <span class="Constant">0</span><span class="Delimiter">)</span> result<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>r<span class="Delimiter">);</span>
      Disable_redefine_checks = <span class="Constant">false</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    <span class="Comment">// End Command Handlers</span>
    <span class="Normal">else</span> <span class="Delimiter">{</span>
      raise &lt;&lt; <span class="Constant">&quot;unknown top-level command: &quot;</span> &lt;&lt; command &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Delimiter">}</span>
  <span class="Delimiter">}</span>
  <span class="Identifier">return</span> result<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Comment">// return the recipe ordinal slurped, or -1 if it failed</span>
<span class="Comment">// (later layers will cause failures)</span>
<span class="Normal">int</span> slurp_recipe<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  recipe result<span class="Delimiter">;</span>
  result<span class="Delimiter">.</span>name = next_word<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>result<span class="Delimiter">.</span>name<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Delimiter">{</span>
    assert<span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">));</span>
    raise &lt;&lt; <span class="Constant">&quot;file ended with 'recipe'</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">return</span> -<span class="Constant">1</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Comment">// End Load Recipe Name</span>
  skip_whitespace_but_not_newline<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  <span class="Comment">// End Recipe Refinements</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>result<span class="Delimiter">.</span>name<span class="Delimiter">.</span>empty<span class="Delimiter">())</span>
    raise &lt;&lt; <span class="Constant">&quot;empty result.name</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;parse&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;--- defining &quot;</span> &lt;&lt; result<span class="Delimiter">.</span>name &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>!contains_key<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> result<span class="Delimiter">.</span>name<span class="Delimiter">))</span>
    put<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> result<span class="Delimiter">.</span>name<span class="Delimiter">,</span> Next_recipe_ordinal++<span class="Delimiter">);</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>Recipe<span class="Delimiter">.</span>find<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> result<span class="Delimiter">.</span>name<span class="Delimiter">))</span> != Recipe<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Delimiter">{</span>
    trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;parse&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;already exists&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>should_check_for_redefine<span class="Delimiter">(</span>result<span class="Delimiter">.</span>name<span class="Delimiter">))</span>
      raise &lt;&lt; <span class="Constant">&quot;redefining recipe &quot;</span> &lt;&lt; result<span class="Delimiter">.</span>name &lt;&lt; <span class="Constant">&quot;</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    Recipe<span class="Delimiter">.</span>erase<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> result<span class="Delimiter">.</span>name<span class="Delimiter">));</span>
  <span class="Delimiter">}</span>
  slurp_body<span class="Delimiter">(</span>in<span class="Delimiter">,</span> result<span class="Delimiter">);</span>
  <span class="Comment">// End Recipe Body(result)</span>
  put<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> get<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> result<span class="Delimiter">.</span>name<span class="Delimiter">),</span> result<span class="Delimiter">);</span>
  <span class="Identifier">return</span> get<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> result<span class="Delimiter">.</span>name<span class="Delimiter">);</span>
<span class="Delimiter">}</span>

<span class="Normal">void</span> slurp_body<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">,</span> recipe&amp; result<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  in &gt;&gt; std::noskipws<span class="Delimiter">;</span>
  skip_whitespace_but_not_newline<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>in<span class="Delimiter">.</span>get<span class="Delimiter">()</span> != <span class="Constant">'['</span><span class="Delimiter">)</span>
    raise &lt;&lt; result<span class="Delimiter">.</span>name &lt;&lt; <span class="Constant">&quot;: recipe body must begin with '['</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
  skip_whitespace_and_comments<span class="Delimiter">(</span>in<span class="Delimiter">);</span>  <span class="Comment">// permit trailing comment after '['</span>
  instruction curr<span class="Delimiter">;</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>next_instruction<span class="Delimiter">(</span>in<span class="Delimiter">,</span> &amp;curr<span class="Delimiter">))</span> <span class="Delimiter">{</span>
    curr<span class="Delimiter">.</span>original_string = to_original_string<span class="Delimiter">(</span>curr<span class="Delimiter">);</span>
    <span class="Comment">// End Rewrite Instruction(curr, recipe result)</span>
    trace<span class="Delimiter">(</span><span class="Constant">9992</span><span class="Delimiter">,</span> <span class="Constant">&quot;load&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;after rewriting: &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>curr<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>!curr<span class="Delimiter">.</span>is_empty<span class="Delimiter">())</span> result<span class="Delimiter">.</span>steps<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>curr<span class="Delimiter">);</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>

<span class="Normal">bool</span> next_instruction<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">,</span> instruction* curr<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  curr<span class="Delimiter">-&gt;</span>clear<span class="Delimiter">();</span>
  skip_whitespace_and_comments<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
    raise &lt;&lt; <span class="Constant">&quot;incomplete recipe at end of file (0)</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>

  vector&lt;string&gt; words<span class="Delimiter">;</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">)</span> &amp;&amp; in<span class="Delimiter">.</span>peek<span class="Delimiter">()</span> != <span class="cSpecial">'\n'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    skip_whitespace_but_not_newline<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
      raise &lt;&lt; <span class="Constant">&quot;incomplete recipe at end of file (1)</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
      <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    string word = next_word<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>word<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Delimiter">{</span>
      assert<span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">));</span>
      raise &lt;&lt; <span class="Constant">&quot;incomplete recipe at end of file (2)</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
      <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    words<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>word<span class="Delimiter">);</span>
    skip_whitespace_but_not_newline<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  <span class="Delimiter">}</span>
  skip_whitespace_and_comments<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>words<span class="Delimiter">)</span> == <span class="Constant">1</span> &amp;&amp; words<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)</span> == <span class="Constant">&quot;]&quot;</span><span class="Delimiter">)</span>
    <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>  <span class="Comment">// end of recipe</span>

  <span class="Normal">if</span> <span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>words<span class="Delimiter">)</span> == <span class="Constant">1</span> &amp;&amp; !isalnum<span class="Delimiter">(</span>words<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">))</span> &amp;&amp; words<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)</span> != <span class="Constant">'$'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    curr<span class="Delimiter">-&gt;</span>is_label = <span class="Constant">true</span><span class="Delimiter">;</span>
    curr<span class="Delimiter">-&gt;</span>label = words<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">);</span>
    trace<span class="Delimiter">(</span><span class="Constant">9993</span><span class="Delimiter">,</span> <span class="Constant">&quot;parse&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;label: &quot;</span> &lt;&lt; curr<span class="Delimiter">-&gt;</span>label &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
      raise &lt;&lt; <span class="Constant">&quot;incomplete recipe at end of file (3)</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
      <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    <span class="Identifier">return</span> <span class="Constant">true</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>

  vector&lt;string&gt;::iterator p = words<span class="Delimiter">.</span>begin<span class="Delimiter">();</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>find<span class="Delimiter">(</span>words<span class="Delimiter">.</span>begin<span class="Delimiter">(),</span> words<span class="Delimiter">.</span>end<span class="Delimiter">(),</span> <span class="Constant">&quot;&lt;-&quot;</span><span class="Delimiter">)</span> != words<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Delimiter">{</span>
    <span class="Normal">for</span> <span class="Delimiter">(;</span>  *p != <span class="Constant">&quot;&lt;-&quot;</span><span class="Delimiter">;</span>  ++p<span class="Delimiter">)</span>
      curr<span class="Delimiter">-&gt;</span>products<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>reagent<span class="Delimiter">(</span>*p<span class="Delimiter">));</span>
    ++p<span class="Delimiter">;</span>  <span class="Comment">// skip &lt;-</span>
  <span class="Delimiter">}</span>

  <span class="Normal">if</span> <span class="Delimiter">(</span>p == words<span class="Delimiter">.</span>end<span class="Delimiter">())</span> <span class="Delimiter">{</span>
    raise &lt;&lt; <span class="Constant">&quot;instruction prematurely ended with '&lt;-'</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  curr<span class="Delimiter">-&gt;</span>old_name = curr<span class="Delimiter">-&gt;</span>name = *p<span class="Delimiter">;</span>  ++p<span class="Delimiter">;</span>
  <span class="Comment">// curr-&gt;operation will be set in a later layer</span>

  <span class="Normal">for</span> <span class="Delimiter">(;</span>  p != words<span class="Delimiter">.</span>end<span class="Delimiter">();</span>  ++p<span class="Delimiter">)</span>
    curr<span class="Delimiter">-&gt;</span>ingredients<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>reagent<span class="Delimiter">(</span>*p<span class="Delimiter">));</span>

  trace<span class="Delimiter">(</span><span class="Constant">9993</span><span class="Delimiter">,</span> <span class="Constant">&quot;parse&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;instruction: &quot;</span> &lt;&lt; curr<span class="Delimiter">-&gt;</span>name &lt;&lt; end<span class="Delimiter">();</span>
  trace<span class="Delimiter">(</span><span class="Constant">9993</span><span class="Delimiter">,</span> <span class="Constant">&quot;parse&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;  number of ingredients: &quot;</span> &lt;&lt; SIZE<span class="Delimiter">(</span>curr<span class="Delimiter">-&gt;</span>ingredients<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Normal">for</span> <span class="Delimiter">(</span>vector&lt;reagent&gt;::iterator p = curr<span class="Delimiter">-&gt;</span>ingredients<span class="Delimiter">.</span>begin<span class="Delimiter">();</span>  p != curr<span class="Delimiter">-&gt;</span>ingredients<span class="Delimiter">.</span>end<span class="Delimiter">();</span>  ++p<span class="Delimiter">)</span>
    trace<span class="Delimiter">(</span><span class="Constant">9993</span><span class="Delimiter">,</span> <span class="Constant">&quot;parse&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;  ingredient: &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>*p<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Normal">for</span> <span class="Delimiter">(</span>vector&lt;reagent&gt;::iterator p = curr<span class="Delimiter">-&gt;</span>products<span class="Delimiter">.</span>begin<span class="Delimiter">();</span>  p != curr<span class="Delimiter">-&gt;</span>products<span class="Delimiter">.</span>end<span class="Delimiter">();</span>  ++p<span class="Delimiter">)</span>
    trace<span class="Delimiter">(</span><span class="Constant">9993</span><span class="Delimiter">,</span> <span class="Constant">&quot;parse&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;  product: &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>*p<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Delimiter">{</span>
    raise &lt;&lt; <span class="Constant">&quot;9: unbalanced '[' for recipe</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Identifier">return</span> <span class="Constant">true</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Comment">// can return empty string -- only if `in` has no more data</span>
string next_word<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  skip_whitespace_but_not_newline<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  <span class="Comment">// End next_word Special-cases</span>
  ostringstream out<span class="Delimiter">;</span>
  slurp_word<span class="Delimiter">(</span>in<span class="Delimiter">,</span> out<span class="Delimiter">);</span>
  skip_whitespace_and_comments_but_not_newline<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  string result = out<span class="Delimiter">.</span>str<span class="Delimiter">();</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>result != <span class="Constant">&quot;[&quot;</span> &amp;&amp; ends_with<span class="Delimiter">(</span>result<span class="Delimiter">,</span> <span class="Constant">'['</span><span class="Delimiter">))</span>
    raise &lt;&lt; <span class="Constant">&quot;insert a space before '[' in '&quot;</span> &lt;&lt; result &lt;&lt; <span class="Constant">&quot;'</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Identifier">return</span> result<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Normal">bool</span> ends_with<span class="Delimiter">(</span><span class="Normal">const</span> string&amp; s<span class="Delimiter">,</span> <span class="Normal">const</span> <span class="Normal">char</span> c<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>s<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
  <span class="Identifier">return</span> *s<span class="Delimiter">.</span>rbegin<span class="Delimiter">()</span> == c<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(before &quot;End Globals&quot;)</span>
<span class="Comment">// word boundaries</span>
<span class="Normal">extern</span> <span class="Normal">const</span> string Terminators<span class="Delimiter">(</span><span class="Constant">&quot;(){}&quot;</span><span class="Delimiter">);</span>
<span class="Delimiter">:(code)</span>
<span class="Normal">void</span> slurp_word<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">,</span> ostream&amp; out<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">char</span> c<span class="Delimiter">;</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">)</span> &amp;&amp; Terminators<span class="Delimiter">.</span>find<span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">())</span> != string::npos<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    in &gt;&gt; c<span class="Delimiter">;</span>
    out &lt;&lt; c<span class="Delimiter">;</span>
    <span class="Identifier">return</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>in &gt;&gt; c<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>isspace<span class="Delimiter">(</span>c<span class="Delimiter">)</span> || Terminators<span class="Delimiter">.</span>find<span class="Delimiter">(</span>c<span class="Delimiter">)</span> != string::npos || Ignore<span class="Delimiter">.</span>find<span class="Delimiter">(</span>c<span class="Delimiter">)</span> != string::npos<span class="Delimiter">)</span> <span class="Delimiter">{</span>
      in<span class="Delimiter">.</span>putback<span class="Delimiter">(</span>c<span class="Delimiter">);</span>
      <span class="Identifier">break</span><span class="Delimiter">;</span>
    <span class="Delimiter">}</span>
    out &lt;&lt; c<span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>

<span class="Normal">void</span> skip_whitespace_and_comments<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span><span class="Constant">true</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>isspace<span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">()))</span> in<span class="Delimiter">.</span>get<span class="Delimiter">();</span>
    <span class="Normal">else</span> <span class="Normal">if</span> <span class="Delimiter">(</span>Ignore<span class="Delimiter">.</span>find<span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">())</span> != string::npos<span class="Delimiter">)</span> in<span class="Delimiter">.</span>get<span class="Delimiter">();</span>
    <span class="Normal">else</span> <span class="Normal">if</span> <span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">()</span> == <span class="Constant">'#'</span><span class="Delimiter">)</span> skip_comment<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
    <span class="Normal">else</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>

<span class="Comment">// confusing; move to the next line only to skip a comment, but never otherwise</span>
<span class="Normal">void</span> skip_whitespace_and_comments_but_not_newline<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span><span class="Constant">true</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>!has_data<span class="Delimiter">(</span>in<span class="Delimiter">))</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">()</span> == <span class="cSpecial">'\n'</span><span class="Delimiter">)</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>isspace<span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">()))</span> in<span class="Delimiter">.</span>get<span class="Delimiter">();</span>
    <span class="Normal">else</span> <span class="Normal">if</span> <span class="Delimiter">(</span>Ignore<span class="Delimiter">.</span>find<span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">())</span> != string::npos<span class="Delimiter">)</span> in<span class="Delimiter">.</span>get<span class="Delimiter">();</span>
    <span class="Normal">else</span> <span class="Normal">if</span> <span class="Delimiter">(</span>in<span class="Delimiter">.</span>peek<span class="Delimiter">()</span> == <span class="Constant">'#'</span><span class="Delimiter">)</span> skip_comment<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
    <span class="Normal">else</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>

<span class="Normal">void</span> skip_comment<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">)</span> &amp;&amp; in<span class="Delimiter">.</span>peek<span class="Delimiter">()</span> == <span class="Constant">'#'</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    in<span class="Delimiter">.</span>get<span class="Delimiter">();</span>
    <span class="Normal">while</span> <span class="Delimiter">(</span>has_data<span class="Delimiter">(</span>in<span class="Delimiter">)</span> &amp;&amp; in<span class="Delimiter">.</span>peek<span class="Delimiter">()</span> != <span class="cSpecial">'\n'</span><span class="Delimiter">)</span> in<span class="Delimiter">.</span>get<span class="Delimiter">();</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(scenario recipe_instead_of_def)</span>
<span class="muRecipe">recipe</span> main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>

<span class="Delimiter">:(scenario parse_comment_outside_recipe)</span>
<span class="Comment"># this comment will be dropped by the tangler, so we need a dummy recipe to stop that</span>
<span class="muRecipe">def</span> f1 [
]
<span class="Comment"># this comment will go through to 'load'</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>

<span class="Delimiter">:(scenario parse_comment_amongst_instruction)</span>
<span class="muRecipe">def</span> main [
  <span class="Comment"># comment</span>
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>

<span class="Delimiter">:(scenario parse_comment_amongst_instruction_2)</span>
<span class="muRecipe">def</span> main [
  <span class="Comment"># comment</span>
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
  <span class="Comment"># comment</span>
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>

<span class="Delimiter">:(scenario parse_comment_amongst_instruction_3)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
  <span class="Comment"># comment</span>
  <span class="Constant">2</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   product: {2: &quot;number&quot;}</span>

<span class="Delimiter">:(scenario parse_comment_after_instruction)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>  <span class="Comment"># comment</span>
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>

<span class="Delimiter">:(scenario parse_label)</span>
<span class="muRecipe">def</span> main [
  +foo
]
<span class="traceContains">+parse: label: +foo</span>

<span class="Delimiter">:(scenario parse_dollar_as_recipe_name)</span>
<span class="muRecipe">def</span> main [
  $foo
]
<span class="traceContains">+parse: instruction: $foo</span>

<span class="Delimiter">:(scenario parse_multiple_properties)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>/foo:bar:baz
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;, &quot;foo&quot;: (&quot;bar&quot; &quot;baz&quot;)}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>

<span class="Delimiter">:(scenario parse_multiple_products)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Delimiter">,</span> <span class="Constant">2</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>
<span class="traceContains">+parse:   product: {2: &quot;number&quot;}</span>

<span class="Delimiter">:(scenario parse_multiple_ingredients)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Delimiter">,</span> <span class="Constant">2</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span><span class="Delimiter">,</span> <span class="Constant">4</span>:number
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   ingredient: {4: &quot;number&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>
<span class="traceContains">+parse:   product: {2: &quot;number&quot;}</span>

<span class="Delimiter">:(scenario parse_multiple_types)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Delimiter">,</span> <span class="Constant">2</span>:address:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span><span class="Delimiter">,</span> <span class="Constant">4</span>:number
]
<span class="traceContains">+parse: instruction: copy</span>
<span class="traceContains">+parse:   ingredient: {23: &quot;literal&quot;}</span>
<span class="traceContains">+parse:   ingredient: {4: &quot;number&quot;}</span>
<span class="traceContains">+parse:   product: {1: &quot;number&quot;}</span>
<span class="traceContains">+parse:   product: {2: (&quot;address&quot; &quot;number&quot;)}</span>

<span class="Delimiter">:(scenario parse_properties)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:address:number/lookup<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="traceContains">+parse:   product: {1: (&quot;address&quot; &quot;number&quot;), &quot;lookup&quot;: ()}</span>

<span class="Comment">//: this test we can't represent with a scenario</span>
<span class="Delimiter">:(code)</span>
<span class="Normal">void</span> test_parse_comment_terminated_by_eof<span class="Delimiter">()</span> <span class="Delimiter">{</span>
  load<span class="Delimiter">(</span><span class="Constant">&quot;recipe main [</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       <span class="Constant">&quot;  a:number &lt;- copy 34</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       <span class="Constant">&quot;]</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span>
       <span class="Constant">&quot;# abc&quot;</span><span class="Delimiter">);</span>  <span class="Comment">// no newline after comment</span>
  cerr &lt;&lt; <span class="Constant">&quot;.&quot;</span><span class="Delimiter">;</span>  <span class="Comment">// termination = success</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(scenario warn_on_missing_space_before_bracket)</span>
<span class="Special">% Hide_errors = true;</span>
<span class="muRecipe">def</span> main[
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="traceContains">+error: insert a space before '[' in 'main['</span>

<span class="Comment">//: Warn if a recipe gets redefined, because large codebases can accidentally</span>
<span class="Comment">//: step on their own toes. But there'll be many occasions later where</span>
<span class="Comment">//: we'll want to disable the errors.</span>
<span class="Delimiter">:(before &quot;End Globals&quot;)</span>
<span class="Normal">bool</span> Disable_redefine_checks = <span class="Constant">false</span><span class="Delimiter">;</span>
<span class="Delimiter">:(before &quot;End Setup&quot;)</span>
Disable_redefine_checks = <span class="Constant">false</span><span class="Delimiter">;</span>
<span class="Delimiter">:(code)</span>
<span class="Normal">bool</span> should_check_for_redefine<span class="Delimiter">(</span><span class="Normal">const</span> string&amp; recipe_name<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>Disable_redefine_checks<span class="Delimiter">)</span> <span class="Identifier">return</span> <span class="Constant">false</span><span class="Delimiter">;</span>
  <span class="Identifier">return</span> <span class="Constant">true</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(scenario forbid_redefining_recipes)</span>
<span class="Special">% Hide_errors = true;</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">24</span>
]
<span class="traceContains">+error: redefining recipe main</span>

<span class="Delimiter">:(scenario permit_forcibly_redefining_recipes)</span>
<span class="muRecipe">def</span> main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">23</span>
]
<span class="muRecipe">def</span>! main [
  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">24</span>
]
<span class="traceAbsent">-error: redefining recipe main</span>
$error: <span class="Constant">0</span>

<span class="Delimiter">:(code)</span>
<span class="Comment">// for debugging</span>
<span class="Normal">void</span> show_rest_of_stream<span class="Delimiter">(</span>istream&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  cerr &lt;&lt; <span class="Constant">'^'</span><span class="Delimiter">;</span>
  <span class="Normal">char</span> c<span class="Delimiter">;</span>
  <span class="Normal">while</span> <span class="Delimiter">(</span>in &gt;&gt; c<span class="Delimiter">)</span>
    cerr &lt;&lt; c<span class="Delimiter">;</span>
  cerr &lt;&lt; <span class="Constant">&quot;$</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span><span class="Delimiter">;</span>
  exit<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">);</span>
<span class="Delimiter">}</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->