Numeric types

The num<> type

CAMP includes constructs for compile time numerical types which can be used in almost any other camp construct. The num<> type is an integral constant type, rather than a constant value. Let’s look at the difference:

constexpr int myVal = 0;
// This is a numeric value,
using myNum = camp::num<0>;
// This is a type, which holds onto the value 0 as part of its template type information,
// so it can be used with other camp features (such as list) which act on types rather than values

Index Sequences

Camp provides compile time methods to generate sequences of index types. The most basic is make_idx_seq, which constructs a sequence of integers starting from zero, and ending at the integral value specified.

using seqType = make_idx_seq_t<4>;
// seqType is idx_seq<0, 1, 2, 3>

Index sequences can also be created using a list (or other sized construct) that already contains data using the make_idx_seq_for template.

using listType = camp::list<int, char>
using seqType = make_idx_seq_for_t<=listType>;
// seqType is idx_seq<0, 1>