abstract structure

An abstract structure defines a set of components, the relationships between those components, and a set of constraints that hold for the structure.

Description

Each abstract structure implies a set of operations that may be performed on the structure. The structure definition, together with that set of operations, is called an abstract data type. Tcl is composed of a layered set of abstract structures:

string

The fundamental structure.

word

Defined in terms of string.

list

Defined in terms of word.

dict

Defined in terms of list, with an additional constraint, and additional operations. The operations it implies is a superset of the operations that list implies.

Additionally, there are two programmatic abstract structures:

command

Defined in terms of words and substitutions.

script

Defined in terms of command.