<!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 - 031merge.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; } .cSpecial { color: #008000; } .traceContains { color: #008000; } .Comment { color: #9090ff; } .Delimiter { color: #800080; } .Special { color: #c00000; } .Identifier { color: #fcb165; } .Normal { color: #eeeeee; background-color: #080808; padding-bottom: 1px; } .PreProc { color: #800080; } --> </style> <script type='text/javascript'> <!-- --> </script> </head> <body> <pre id='vimCodeElement'> <span class="Comment">//: Construct types out of their constituent fields.</span> <span class="Delimiter">:(scenario merge)</span> container foo [ <span class="Normal">x</span>:number <span class="Normal">y</span>:number ] def main [ <span class="Constant">1</span>:foo<span class="Special"> <- </span>merge <span class="Constant">3</span><span class="Delimiter">,</span> <span class="Constant">4</span> ] <span class="traceContains">+mem: storing 3 in location 1</span> <span class="traceContains">+mem: storing 4 in location 2</span> <span class="Delimiter">:(before "End Primitive Recipe Declarations")</span> MERGE<span class="Delimiter">,</span> <span class="Delimiter">:(before "End Primitive Recipe Numbers")</span> put<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">"merge"</span><span class="Delimiter">,</span> MERGE<span class="Delimiter">);</span> <span class="Delimiter">:(before "End Primitive Recipe Checks")</span> <span class="Normal">case</span> MERGE: <span class="Delimiter">{</span> <span class="Comment">// type-checking in a separate transform below</span> <span class="Identifier">break</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> <span class="Delimiter">:(before "End Primitive Recipe Implementations")</span> <span class="Normal">case</span> MERGE: <span class="Delimiter">{</span> products<span class="Delimiter">.</span>resize<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span> <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> i = <span class="Constant">0</span><span class="Delimiter">;</span> i < SIZE<span class="Delimiter">(</span>ingredients<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span> <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> j = <span class="Constant">0</span><span class="Delimiter">;</span> j < SIZE<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">));</span> ++j<span class="Delimiter">)</span> products<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>push_back<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">).</span>at<span class="Delimiter">(</span>j<span class="Delimiter">));</span> <span class="Identifier">break</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> <span class="Comment">//: type-check 'merge' to avoid interpreting numbers as addresses</span> <span class="Delimiter">:(scenario merge_check)</span> def main [ <span class="Constant">1</span>:point<span class="Special"> <- </span>merge <span class="Constant">3</span><span class="Delimiter">,</span> <span class="Constant">4</span> ] $error: <span class="Constant">0</span> <span class="Delimiter">:(scenario merge_check_missing_element)</span> <span class="Special">% Hide_errors = true;</span> def main [ <span class="Constant">1</span>:point<span class="Special"> <- </span>merge <span class="Constant">3</span> ] <span class="traceContains">+error: main: too few ingredients in '1:point <- merge 3'</span> <span class="Delimiter">:(scenario merge_check_extra_element)</span> <span class="Special">% Hide_errors = true;</span> def main [ <span class="Constant">1</span>:point<span class="Special"> <- </span>merge <span class="Constant">3</span><span class="Delimiter">,</span> <span class="Constant">4</span><span class="Delimiter">,</span> <span class="Constant">5</span> ] <span class="traceContains">+error: main: too many ingredients in '1:point <- merge 3, 4, 5'</span> <span class="Comment">//: We want to avoid causing memory corruption, but other than that we want to</span> <span class="Comment">//: be flexible in how we construct containers of containers. It should be</span> <span class="Comment">//: equally easy to define a container out of primitives or intermediate</span> <span class="Comment">//: container fields.</span> <span class="Delimiter">:(scenario merge_check_recursive_containers)</span> def main [ <span class="Constant">1</span>:point<span class="Special"> <- </span>merge <span class="Constant">3</span><span class="Delimiter">,</span> <span class="Constant">4</span> <span class="Constant">1</span>:point-number<span class="Special"> <- </span>merge <span class="Constant">1</span>:point<span class="Delimiter">,</span> <span class="Constant">5</span> ] $error: <span class="Constant">0</span> <span class="Delimiter">:(scenario merge_check_recursive_containers_2)</span> <span class="Special">% Hide_errors = true;</span> def main [ <span class="Constant">1</span>:point<span class="Special"> <- </span>merge <span class="Constant">3</span><span class="Delimiter">,</span> <span class="Constant">4</span> <span class="Constant">2</span>:point-number<span class="Special"> <- </span>merge <span class="Constant">1</span>:point ] <span class="traceContains">+error: main: too few ingredients in '2:point-number <- merge 1:point'</span> <span class="Delimiter">:(scenario merge_check_recursive_containers_3)</span> def main [ <span class="Constant">1</span>:point-number<span class="Special"> <- </span>merge <span class="Constant">3</span><span class="Delimiter">,</span> <span class="Constant">4</span><span class="Delimiter">,</span> <span class="Constant">5</span> ] $error: <span class="Constant">0</span> <span class="Delimiter">:(scenario merge_check_recursive_containers_4)</span> <span class="Special">% Hide_errors = true;</span> def main [ <span class="Constant">1</span>:point-number<span class="Special"> <- </span>merge <span class="Constant">3</span><span class="Delimiter">,</span> <span class="Constant">4</span> ] <span class="traceContains">+error: main: too few ingredients in '1:point-number <- merge 3, 4'</span> <span class="Delimiter">:(scenario merge_check_reflexive)</span> <span class="Special">% Hide_errors = true;</span> def main [ <span class="Constant">1</span>:point<span class="Special"> <- </span>merge <span class="Constant">3</span><span class="Delimiter">,</span> <span class="Constant">4</span> <span class="Constant">2</span>:point<span class="Special"> <- </span>merge <span class="Constant">1</span>:point ] $error: <span class="Constant">0</span> <span class="Comment">//: Since a container can be merged in several ways, we need to be able to</span> <span class="Comment">//: backtrack through different possibilities. Later we'll allow creating</span> <span class="Comment">//: exclusive containers which contain just one of rather than all of their</span> <span class="Comment">//: elements. That will also require backtracking capabilities. Here's the</span> <span class="Comment">//: state we need to maintain for backtracking:</span> <span class="Delimiter">:(before "End Types")</span> <span class="Normal">struct</span> merge_check_point <span class="Delimiter">{</span> reagent container<span class="Delimiter">;</span> <span class="Normal">int</span> container_element_index<span class="Delimiter">;</span> merge_check_point<span class="Delimiter">(</span><span class="Normal">const</span> reagent& c<span class="Delimiter">,</span> <span class="Normal">int</span> i<span class="Delimiter">)</span> :container<span class="Delimiter">(</span>c<span class="Delimiter">),</span> container_element_index<span class="Delimiter">(</span>i<span class="Delimiter">)</span> <span class="Delimiter">{}</span> <span class="Delimiter">};</span> <span class="Normal">struct</span> merge_check_state <span class="Delimiter">{</span> stack<merge_check_point> data<span class="Delimiter">;</span> <span class="Delimiter">};</span> <span class="Delimiter">:(before "End Checks")</span> Transform<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>check_merge_calls<span class="Delimiter">);</span> <span class="Delimiter">:(code)</span> <span class="Normal">void</span> check_merge_calls<span class="Delimiter">(</span><span class="Normal">const</span> recipe_ordinal r<span class="Delimiter">)</span> <span class="Delimiter">{</span> <span class="Normal">const</span> recipe& caller = get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">);</span> trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">"transform"</span><span class="Delimiter">)</span> << <span class="Constant">"--- type-check merge instructions in recipe "</span> << caller<span class="Delimiter">.</span>name << end<span class="Delimiter">();</span> <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> i = <span class="Constant">0</span><span class="Delimiter">;</span> i < SIZE<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>steps<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span> <span class="Normal">const</span> instruction& inst = caller<span class="Delimiter">.</span>steps<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">);</span> <span class="Normal">if</span> <span class="Delimiter">(</span>inst<span class="Delimiter">.</span>name != <span class="Constant">"merge"</span><span class="Delimiter">)</span> <span class="Identifier">continue</span><span class="Delimiter">;</span> <span class="Normal">if</span> <span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>products<span class="Delimiter">)</span> != <span class="Constant">1</span><span class="Delimiter">)</span> <span class="Delimiter">{</span> raise << maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> << <span class="Constant">"'merge' should yield a single product in '"</span> << inst<span class="Delimiter">.</span>original_string << <span class="Constant">"'</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span> <span class="Identifier">continue</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> reagent<span class="Comment">/*</span><span class="Comment">copy</span><span class="Comment">*/</span> product = inst<span class="Delimiter">.</span>products<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">);</span> <span class="Comment">// Update product While Type-checking Merge</span> type_ordinal product_type = product<span class="Delimiter">.</span>type<span class="Delimiter">-></span>value<span class="Delimiter">;</span> <span class="Normal">if</span> <span class="Delimiter">(</span>product_type == <span class="Constant">0</span> || !contains_key<span class="Delimiter">(</span>Type<span class="Delimiter">,</span> product_type<span class="Delimiter">))</span> <span class="Delimiter">{</span> raise << maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> << <span class="Constant">"'merge' should yield a container in '"</span> << inst<span class="Delimiter">.</span>original_string << <span class="Constant">"'</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span> <span class="Identifier">continue</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> <span class="Normal">const</span> type_info& info = get<span class="Delimiter">(</span>Type<span class="Delimiter">,</span> product_type<span class="Delimiter">);</span> <span class="Normal">if</span> <span class="Delimiter">(</span>info<span class="Delimiter">.</span>kind != CONTAINER && info<span class="Delimiter">.</span>kind != EXCLUSIVE_CONTAINER<span class="Delimiter">)</span> <span class="Delimiter">{</span> raise << maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> << <span class="Constant">"'merge' should yield a container in '"</span> << inst<span class="Delimiter">.</span>original_string << <span class="Constant">"'</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span> <span class="Identifier">continue</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> check_merge_call<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">,</span> product<span class="Delimiter">,</span> caller<span class="Delimiter">,</span> inst<span class="Delimiter">);</span> <span class="Delimiter">}</span> <span class="Delimiter">}</span> <span class="Normal">void</span> check_merge_call<span class="Delimiter">(</span><span class="Normal">const</span> vector<reagent>& ingredients<span class="Delimiter">,</span> <span class="Normal">const</span> reagent& product<span class="Delimiter">,</span> <span class="Normal">const</span> recipe& caller<span class="Delimiter">,</span> <span class="Normal">const</span> instruction& inst<span class="Delimiter">)</span> <span class="Delimiter">{</span> <span class="Normal">int</span> ingredient_index = <span class="Constant">0</span><span class="Delimiter">;</span> merge_check_state state<span class="Delimiter">;</span> state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>push<span class="Delimiter">(</span>merge_check_point<span class="Delimiter">(</span>product<span class="Delimiter">,</span> <span class="Constant">0</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> assert<span class="Delimiter">(</span>!state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>empty<span class="Delimiter">());</span> trace<span class="Delimiter">(</span><span class="Constant">9999</span><span class="Delimiter">,</span> <span class="Constant">"transform"</span><span class="Delimiter">)</span> << ingredient_index << <span class="Constant">" vs "</span> << SIZE<span class="Delimiter">(</span>ingredients<span class="Delimiter">)</span> << end<span class="Delimiter">();</span> <span class="Normal">if</span> <span class="Delimiter">(</span>ingredient_index >= SIZE<span class="Delimiter">(</span>ingredients<span class="Delimiter">))</span> <span class="Delimiter">{</span> raise << maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> << <span class="Constant">"too few ingredients in '"</span> << inst<span class="Delimiter">.</span>original_string << <span class="Constant">"'</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span> <span class="Identifier">return</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> reagent& container = state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container<span class="Delimiter">;</span> <span class="Normal">if</span> <span class="Delimiter">(</span>!container<span class="Delimiter">.</span>type<span class="Delimiter">)</span> <span class="Identifier">return</span><span class="Delimiter">;</span> <span class="Comment">// error handled elsewhere</span> type_info& container_info = get<span class="Delimiter">(</span>Type<span class="Delimiter">,</span> container<span class="Delimiter">.</span>type<span class="Delimiter">-></span>value<span class="Delimiter">);</span> <span class="Normal">switch</span> <span class="Delimiter">(</span>container_info<span class="Delimiter">.</span>kind<span class="Delimiter">)</span> <span class="Delimiter">{</span> <span class="Normal">case</span> CONTAINER: <span class="Delimiter">{</span> <span class="Comment">// degenerate case: merge with the same type always succeeds</span> <span class="Normal">if</span> <span class="Delimiter">(</span>state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container_element_index == <span class="Constant">0</span> && types_coercible<span class="Delimiter">(</span>container<span class="Delimiter">,</span> inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>ingredient_index<span class="Delimiter">)))</span> <span class="Identifier">return</span><span class="Delimiter">;</span> <span class="Normal">const</span> reagent& expected_ingredient = element_type<span class="Delimiter">(</span>container<span class="Delimiter">.</span>type<span class="Delimiter">,</span> state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container_element_index<span class="Delimiter">);</span> trace<span class="Delimiter">(</span><span class="Constant">9999</span><span class="Delimiter">,</span> <span class="Constant">"transform"</span><span class="Delimiter">)</span> << <span class="Constant">"checking container "</span> << to_string<span class="Delimiter">(</span>container<span class="Delimiter">)</span> << <span class="Constant">" || "</span> << to_string<span class="Delimiter">(</span>expected_ingredient<span class="Delimiter">)</span> << <span class="Constant">" vs ingredient "</span> << ingredient_index << end<span class="Delimiter">();</span> <span class="Comment">// if the current element is the ingredient we expect, move on to the next element/ingredient</span> <span class="Normal">if</span> <span class="Delimiter">(</span>types_coercible<span class="Delimiter">(</span>expected_ingredient<span class="Delimiter">,</span> ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>ingredient_index<span class="Delimiter">)))</span> <span class="Delimiter">{</span> ++ingredient_index<span class="Delimiter">;</span> ++state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container_element_index<span class="Delimiter">;</span> <span class="Normal">while</span> <span class="Delimiter">(</span>state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container_element_index >= SIZE<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Type<span class="Delimiter">,</span> state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container<span class="Delimiter">.</span>type<span class="Delimiter">-></span>value<span class="Delimiter">).</span>elements<span class="Delimiter">))</span> <span class="Delimiter">{</span> state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>pop<span class="Delimiter">();</span> <span class="Normal">if</span> <span class="Delimiter">(</span>state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Delimiter">{</span> <span class="Normal">if</span> <span class="Delimiter">(</span>ingredient_index < SIZE<span class="Delimiter">(</span>ingredients<span class="Delimiter">))</span> raise << maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> << <span class="Constant">"too many ingredients in '"</span> << inst<span class="Delimiter">.</span>original_string << <span class="Constant">"'</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span> <span class="Identifier">return</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> ++state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container_element_index<span class="Delimiter">;</span> <span class="Delimiter">}</span> <span class="Delimiter">}</span> <span class="Comment">// if not, maybe it's a field of the current element</span> <span class="Normal">else</span> <span class="Delimiter">{</span> <span class="Comment">// no change to ingredient_index</span> state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>push<span class="Delimiter">(</span>merge_check_point<span class="Delimiter">(</span>expected_ingredient<span class="Delimiter">,</span> <span class="Constant">0</span><span class="Delimiter">));</span> <span class="Delimiter">}</span> <span class="Identifier">break</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> <span class="Comment">// End check_merge_call Cases</span> <span class="Normal">default</span>: <span class="Delimiter">{</span> <span class="Normal">if</span> <span class="Delimiter">(</span>!types_coercible<span class="Delimiter">(</span>container<span class="Delimiter">,</span> ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>ingredient_index<span class="Delimiter">)))</span> <span class="Delimiter">{</span> raise << maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> << <span class="Constant">"incorrect type of ingredient "</span> << ingredient_index << <span class="Constant">" in '"</span> << inst<span class="Delimiter">.</span>original_string << <span class="Constant">"'</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span> raise << <span class="Constant">" (expected '"</span> << debug_string<span class="Delimiter">(</span>container<span class="Delimiter">)</span> << <span class="Constant">"')</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span> raise << <span class="Constant">" (got '"</span> << debug_string<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>ingredient_index<span class="Delimiter">))</span> << <span class="Constant">"')</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span> <span class="Identifier">return</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> ++ingredient_index<span class="Delimiter">;</span> <span class="Comment">// ++state.data.top().container_element_index; // unnecessary, but wouldn't do any harm</span> <span class="Normal">do</span> <span class="Delimiter">{</span> state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>pop<span class="Delimiter">();</span> <span class="Normal">if</span> <span class="Delimiter">(</span>state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Delimiter">{</span> <span class="Normal">if</span> <span class="Delimiter">(</span>ingredient_index < SIZE<span class="Delimiter">(</span>ingredients<span class="Delimiter">))</span> raise << maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> << <span class="Constant">"too many ingredients in '"</span> << inst<span class="Delimiter">.</span>original_string << <span class="Constant">"'</span><span class="cSpecial">\n</span><span class="Constant">"</span> << end<span class="Delimiter">();</span> <span class="Identifier">return</span><span class="Delimiter">;</span> <span class="Delimiter">}</span> ++state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container_element_index<span class="Delimiter">;</span> <span class="Delimiter">}</span> <span class="Normal">while</span> <span class="Delimiter">(</span>state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container_element_index >= SIZE<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Type<span class="Delimiter">,</span> state<span class="Delimiter">.</span>data<span class="Delimiter">.</span>top<span class="Delimiter">().</span>container<span class="Delimiter">.</span>type<span class="Delimiter">-></span>value<span class="Delimiter">).</span>elements<span class="Delimiter">));</span> <span class="Delimiter">}</span> <span class="Delimiter">}</span> <span class="Delimiter">}</span> <span class="Comment">// never gets here</span> assert<span class="Delimiter">(</span><span class="Constant">false</span><span class="Delimiter">);</span> <span class="Delimiter">}</span> <span class="Delimiter">:(scenario merge_check_product)</span> <span class="Special">% Hide_errors = true;</span> def main [ <span class="Constant">1</span>:number<span class="Special"> <- </span>merge <span class="Constant">3</span> ] <span class="traceContains">+error: main: 'merge' should yield a container in '1:number <- merge 3'</span> <span class="Delimiter">:(before "End Includes")</span> <span class="PreProc">#include </span><span class="Constant"><stack></span> <span class="Normal">using</span> std::stack<span class="Delimiter">;</span> </pre> </body> </html> <!-- vim: set foldmethod=manual : -->