Analysis support for table-valued functions

sqlparser/lib/src/analysis/context.dart

@@ -17,6 +17,12 @@ class AnalysisContext {
   /// outside.
   final AnalyzeStatementOptions stmtOptions;
 
+  /// Options passed to the surrounding engine.
+  ///
+  /// This contains information about enabled sqlite modules and how to resolve
+  /// some functions.
+  final EngineOptions engineOptions;
+
   /// Utilities to read types.
   final SchemaFromCreateTable schemaSupport;
 
@@ -40,11 +46,11 @@ class AnalysisContext {
   TypeInferenceResults types2;
 
   /// Constructs a new analysis context from the AST and the source sql.
-  AnalysisContext(this.root, this.sql, EngineOptions options,
+  AnalysisContext(this.root, this.sql, this.engineOptions,
       {AnalyzeStatementOptions stmtOptions, this.schemaSupport})
       : stmtOptions = stmtOptions ?? const AnalyzeStatementOptions() {
-    if (!options.enableExperimentalTypeInference) {
-      types = TypeResolver(this, options);
+    if (!engineOptions.enableExperimentalTypeInference) {
+      types = TypeResolver(this, engineOptions);
     }
   }
 

sqlparser/lib/src/analysis/steps/column_resolver.dart

@@ -135,6 +135,29 @@ class ColumnResolver extends RecursiveVisitor<void, void> {
           _handle(query, availableColumns);
         }
       },
+      isTableFunction: (function) {
+        final functions = context.engineOptions.addedFunctions;
+        final lowercaseName = function.name.toLowerCase();
+        ResultSet resolved;
+
+        if (functions.containsKey(lowercaseName)) {
+          final handler = functions[lowercaseName];
+          if (handler is TableValuedFunctionHandler) {
+            resolved = handler.resolveTableValued(context, function);
+          }
+        }
+
+        if (resolved == null) {
+          context.reportError(AnalysisError(
+            type: AnalysisErrorType.unknownFunction,
+            message: 'Could not extract the result set for this table function',
+            relevantNode: function,
+          ));
+        } else {
+          function.resultSet = resolved;
+          availableColumns.addAll(resolved.resolvedColumns);
+        }
+      },
     );
   }
 

sqlparser/lib/src/analysis/steps/prepare_ast.dart

@@ -118,6 +118,12 @@ class AstPreparingVisitor extends RecursiveVisitor<void, void> {
         // Queryables, so we can deal with them by visiting the children and
         // dont't need to do anything here.
       },
+      isTableFunction: (function) {
+        if (function.as != null) {
+          scope.register(function.as, function);
+        }
+        scope.register(function.name, function);
+      },
     );
 
     visitChildren(e, arg);

sqlparser/lib/src/ast/common/queryables.dart

@@ -171,7 +171,7 @@ class UsingConstraint extends JoinConstraint {
 }
 
 class TableValuedFunction extends Queryable
-    implements TableOrSubquery, SqlInvocation, Renamable {
+    implements TableOrSubquery, SqlInvocation, Renamable, ResolvesToResultSet {
   @override
   final String name;
 
@@ -181,6 +181,9 @@ class TableValuedFunction extends Queryable
   @override
   final FunctionParameters parameters;
 
+  @override
+  ResultSet resultSet;
+
   TableValuedFunction(this.name, this.parameters, {this.as});
 
   @override

sqlparser/lib/src/engine/module/module.dart

@@ -47,6 +47,17 @@ abstract class FunctionHandler {
   void reportErrors(SqlInvocation call, AnalysisContext context) {}
 }
 
+abstract class TableValuedFunctionHandler implements FunctionHandler {
+  /// Resolve the result set of a table-valued function.
+  ///
+  /// Should return null when the result set can't be resolved.
+  ///
+  /// See also:
+  ///  - https://www.sqlite.org/vtab.html#tabfunc2
+  ResultSet resolveTableValued(
+      AnalysisContext context, TableValuedFunction call);
+}
+
 /// An sqlite module, which can be used in a `CREATE VIRTUAL TABLE` statement
 /// to find providers.
 abstract class Module implements Referencable, VisibleToChildren {