本文整理汇总了C++中ndt::type::is_null方法的典型用法代码示例。如果您正苦于以下问题：C++ type::is_null方法的具体用法？C++ type::is_null怎么用？C++ type::is_null使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类ndt::type的用法示例。
在下文中一共展示了type::is_null方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: parse_struct_item
// record_item : NAME COLON rhs_expression
static bool parse_struct_item(const char *&rbegin, const char *end,
map<string, ndt::type> &symtable,
string &out_field_name, ndt::type &out_field_type)
{
const char *begin = rbegin;
const char *field_name_begin, *field_name_end;
//quoted_out_val and quoted_name are used to hold the field name and to denote if the data given
// to this function needed special handling due to quoting of the struct field names.
string quoted_out_val;
bool quoted_name=false;
parse::skip_whitespace_and_pound_comments(begin, end);
if (parse::parse_name_no_ws(begin, end, field_name_begin, field_name_end)) {
//We successfully parsed a name with no whitespace
//We don't need to do anything else, because field_name_begin
}
else if (parse_quoted_string(begin, end, quoted_out_val)) {
//parse_quoted_string must return a new string for us to use because it will parse
// and potentially replace things in the string (like escaped characters)
//It will also remove the surrounding quotes.
quoted_name=true;
}
else{
//This struct item cannot be parsed. Ergo, we return false for failure.
return false;
}
if (!parse_token_ds(begin, end , ':')) {
throw datashape_parse_error(begin, "expected ':' after record item name");
}
bool parens = false;
if (parse_token_ds(begin, end, '(')) {
parens = true;
}
out_field_type = parse_datashape(begin, end, symtable);
if (out_field_type.is_null()) {
throw datashape_parse_error(begin, "expected a data type");
}
if (parens && !parse_token_ds(begin, end, ')')) {
throw datashape_parse_error(begin, "expected closing ')'");
}
if (!quoted_name) {
//A name that isn't quoted is probably the common case
out_field_name.assign(field_name_begin, field_name_end);
}
else{
//If a field name was quoted, parse_quoted_string() will have parsed and un/re-escaped everything and returned a new string
//The Return of the String is why we have two different out_field_name.assign() cases
out_field_name.assign(quoted_out_val);
}
rbegin = begin;
return true;
}