Function ReplaceFunctionColumn

server/functions/framework/sql_function.go:223–274

ReplaceFunctionColumn parses and replaces UnresolvedName and Placeholder expressions with FunctionColumn expression containing parameter type and arguments if applicable. It also replaces empty parameter name with binding variable name to match the name used in FunctionColumn. This function should b

(parsedAST tree.Statement, params map[string]*ParamTypAndValue)

// It also replaces empty parameter name with binding variable name to match the name used in FunctionColumn.
// This function should be used for FUNCTION with SQL language statements only.
func ReplaceFunctionColumn(parsedAST tree.Statement, params map[string]*ParamTypAndValue) error {
	if len(params) == 0 {
		return nil
	}
	// Function's final statement must be SELECT or INSERT/UPDATE/DELETE RETURNING
	switch s := parsedAST.(type) {
	case *tree.Select:
		switch t := s.Select.(type) {
		case *tree.SelectClause:
			for i, e := range t.Exprs {
				t.Exprs[i].Expr = ReplaceUnresolvedToFunctionColumn(params, e.Expr)
			}
			if t.Where != nil {
				t.Where.Expr = ReplaceUnresolvedToFunctionColumn(params, t.Where.Expr)
			}
		case *tree.ValuesClause:
			for i, row := range t.Rows {
				for j, e := range row {
					row[j] = ReplaceUnresolvedToFunctionColumn(params, e)
				}
				t.Rows[i] = row
			}
		}
		return nil
	case *tree.Insert:
		err := ReplaceFunctionColumn(s.Rows, params)
		if err != nil {
			return err
		}
		return nil
	case *tree.Update:
		for i, e := range s.Exprs {
			s.Exprs[i].Expr = ReplaceUnresolvedToFunctionColumn(params, e.Expr)
		}
		if s.Where != nil {
			s.Where.Expr = ReplaceUnresolvedToFunctionColumn(params, s.Where.Expr)
		}
		return nil
	case *tree.Delete:
		if s.Where != nil {
			s.Where.Expr = ReplaceUnresolvedToFunctionColumn(params, s.Where.Expr)
		}
		return nil
	case *tree.Truncate:
		return nil
	case *tree.Return:
		s.Expr = ReplaceUnresolvedToFunctionColumn(params, s.Expr)
		return nil
	default:
		return errors.Errorf("unsupported statement defined in function: %T", parsedAST)
	}
}

// ReplaceUnresolvedToFunctionColumn replaces Placeholder and UnresolvedName expressions with FunctionColumn containing
// parameter type and argument value if applicable when the name of expression matches function parameter.