WiP - do item counting in mstch variants correctly.

map_form.txt

@@ -0,0 +1,85 @@
+apply {{mustache_name}} to {{pages}}
+	A = /html/head/text()
+	struct B
+		C default("n/a") = //table[@class="wikitable sortable"]/tr/td[4]/a/text()
+		D default("0") = //table[@class="wikitable sortable"]/tr/td[3]/text()
+		struct E
+			F = /html/head/inner_names/text()
+			G = /html/head/inner_probabilities/text()
+		end
+		H = /html/head/inner_names/text()
+	end
+	I = /html/head/inner_names/text()
+end
+
+==mustache_name
+blah
+==end
+
+
+The above should result in the following:
+
+A[]
+B[] --- C
+    --- D
+	--- E[] --- F
+	        --- G
+	--- H
+--- I[]
+
+For example, given these query results:
+A[] = {a1, a2, a3}
+C = c1
+D[] = {d1, d2}
+F[] = {f1, f2, f3}
+G = g1
+h = h1
+i = i1
+
+then the complete result in tree form shall be:
+
+{
+	A => [a1, a2, a3],
+	B => [
+		{
+			C => c1,
+			D => d1,
+			E => [
+				{
+					F => f1,
+					G => g1
+				}, {
+					F => f2,
+					G => ""
+				}, {
+					F => f3,
+					G => ""
+				}
+			],
+			H => h1
+		}, {
+			C => "",
+			D => d2,
+			E => [
+				{
+					F => f1,
+					G => g1
+				}, {
+					F => f2,
+					G => ""
+				}, {
+					F => f3,
+					G => ""
+				}
+			],
+			H => ""
+		}
+	]
+}
+
+Please note that:
+
+* arrays inside a struct turn the struct itself into an array, while its items become just single item values
+* if a struct contains no arrays, then the struct shall not become an array - that is, a struct generates an array with as many elements as the largest element in the struct itself
+* there are as many of any one struct as the size of the largest array inside it
+* nested structs get duplicated in every outer struct they are part of; in the example above E has as many elements as there items in F (2, the largest between F and G), and the whole array of E is duplicated in every element of B

src/scraplang/apply.cpp

@@ -173,8 +173,36 @@ namespace duck { namespace sl {
 			MustacheEntry* m_current_mustache;
 		};
 
-		mstch::map to_mustache_dict_recursive (const EntryNode& parNode, std::string_view parSrc, XPathRunner& parRunner) {
+		struct ItemCountingVisitor : public boost::static_visitor<std::size_t> {
+			template <typename T>
+			std::size_t operator()(const T&) const { return 1; }
+			std::size_t operator()(const mstch::array& parItem) const { return parItem.size(); }
+			std::size_t operator()(const std::vector<std::string>& parItem) const { return parItem.size(); }
+		};
+
+		std::size_t largest_array_size_in (mstch::map& parMap) {
+			typedef ItemCountingVisitor ITC;
+			using boost::apply_visitor;
+
+			if (parMap.empty())
+				return 0;
+
+			return apply_visitor(
+				ITC(),
+				std::max_element(parMap.begin(), parMap.end(), [](const auto& a, const auto& b) {
+					return apply_visitor(ITC(), a.second) < apply_visitor(ITC(), b.second);
+				})->second
+			);
+		}
+
+		mstch::map to_mustache_dict_recursive (
+			const EntryNode& parNode,
+			std::string_view parSrc,
+			XPathRunner& parRunner,
+			bool parMakeVecsSameSize
+		) {
 			mstch::map retval;
+
 			for (const XPathElement* xpath : parNode.xpaths) {
 				assert(xpath);
 				std::cout << "Running query for \"" << xpath->name << "\"\n";
@@ -198,8 +226,16 @@ namespace duck { namespace sl {
 
 			for (auto& curr_struct : parNode.structs) {
 				assert(not curr_struct.name.empty());
-				retval[std::string(curr_struct.name)] =
-					to_mustache_dict_recursive(curr_struct, parSrc, parRunner);
+
+				mstch::array extracted_struct;
+				auto new_struct = to_mustache_dict_recursive(curr_struct, parSrc, parRunner, false);
+				const std::size_t extracted_struct_size = largest_array_size_in(new_struct);
+				std::cout << "Largest array size in \"" << curr_struct.name << "\" = " << extracted_struct_size << '\n';
+				for (auto&& itm : new_struct) {
+
+				}
+
+			//	retval[std::string(curr_struct.name)] =
 			}
 
 			return retval;
@@ -220,7 +256,7 @@ namespace duck { namespace sl {
 					assert(false); //not implemented
 				}
 
-				mstch::map curr_entry_map = to_mustache_dict_recursive(entry.second, src_url, parRunner);
+				mstch::map curr_entry_map = to_mustache_dict_recursive(entry.second, src_url, parRunner, false);
 				curr_entry_map.merge(std::move(retval));
 				retval.swap(curr_entry_map);
 			}