Method parse_primary_expression

external/pugixml/pugixml.cpp:8374–8474

PrimaryExpr ::= VariableReference | '(' Expr ')' | Literal | Number | FunctionCall

	    // PrimaryExpr ::= VariableReference | '(' Expr ')' | Literal | Number | FunctionCall
	    xpath_ast_node* parse_primary_expression()
	    {
	    	switch (_lexer.current())
	    	{
	    	case lex_var_ref:
	    	{
				xpath_lexer_string name = _lexer.contents();

				if (!_variables)
					throw_error("Unknown variable: variable set is not provided");

				xpath_variable* var = get_variable(_variables, name.begin, name.end);

				if (!var)
					throw_error("Unknown variable: variable set does not contain the given name");

				_lexer.next();

	    		return new (alloc_node()) xpath_ast_node(ast_variable, var->type(), var);
			}

			case lex_open_brace:
			{
				_lexer.next();

				xpath_ast_node* n = parse_expression();

				if (_lexer.current() != lex_close_brace)
					throw_error("Unmatched braces");

				_lexer.next();

				return n;
			}

			case lex_quoted_string:
			{
				const char_t* value = alloc_string(_lexer.contents());

				xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_string_constant, xpath_type_string, value);
				_lexer.next();

				return n;
			}

			case lex_number:
			{
				double value = 0;

				if (!convert_string_to_number(_lexer.contents().begin, _lexer.contents().end, &value))
					throw_error_oom();

				xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_number_constant, xpath_type_number, value);
				_lexer.next();

				return n;
			}