Slice

Slice is one of the core TVM types — a read-only cursor over a cell. If a cell is a container of bits and references, a slice is the position from which contents are read: “read 32 bits”, “read the next reference”, and so on.

Lifecycle

A typical TVM cell-reading pattern:

1. begin_parse turns a cell into a slice — a cursor at the start.
2. load_uint(n), load_addr(), load_ref() — operations that read by type. Each one advances the cursor.
3. end_parse asserts the slice was fully consumed (anything left over is an error).

Tact and Tolk hide this from you: the compiler generates parsing code from message/struct declarations. In FunC the slice is always explicit.

Slice vs Cell

Property	Cell	Slice
Purpose	hold data	read data
Mutability	immutable	cursor advances
Used in	storage, message body	parsing
Created from	builder.end()	cell.begin_parse()

A cell is the “file”; a slice is the “open reader with a position”.

Things to keep in mind

• A slice doesn’t copy data. It points at the same cell and tracks its current position and remaining bits.
• If a slice still has a child reference, you read it with load_ref() and then begin_parse() on the resulting cell — recursively.
• Gas depends on what you read, not on what the source cell holds. Reading only what you need is a real optimisation.

Slices are the foundation of all parsing: message bodies, contract storage, ABI arguments.