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statements. Only the operators from the ([]) choice and the (
) sequence are present
in rule
S
. A statement is composed of actions stemming from a single modality. If
the basic actions that participate in the formation of a statement come from modality
m
i
, it is noted
E
Am
i
.Inrule
E
, which describes it, only the actions of set
Am
i
are
accepted. The syntax of the model corresponding to this type of interface is given by
the following BNF grammar rules:
S
::=
S
[]
S | S S | E
Am
i
E
Am
i
::=
a
i
;
E
Am
i
| δ
with
a
i
∈ Am
i
An example of this type of HCI is illustrated via the case study presented in
section 4.4.4.
Alternated type
: as for the exclusive type, the statements in an alternative type
interface are composed sequentially. However, a statement can be produced by several
modalities. Thus, the statements in the first
S
rule are indexed by set
AM
, which is
a set of actions produced by a subset of system modalities. The syntax of the model
corresponding to this type of interface is given by the following BNF grammar rules:
S
::=
S
[]
S | S S | E
AM
E
AM
::=
a
;
E
AM
| a|||E
AM
| δ
with
a ∈ AM
Synergistic type
: in synergistic type HCI, the statements are composed
sequentially. Thus, in the
S
rule we will only keep the sequence and choice operators.
The statements can be produced by several modalities, as well as the actions that
participate in their realization, which are considered in set
AM
. The basic interactive
actions can be produced in parallel or interleaved, which explains the use of parallel
operators (
) in the rule that generates statements. The
syntax of the model corresponding to this type of interface is given by the following
BNF grammar rules:
||
) and parallel interleaved (
|||
S
::=
S
[]
S | S S | E
AM
E
AM
::=
a
;
E
AM
| a|||E
AM
| a||E
AM
| δ
with
a ∈ AM
Exclusive parallel type
: contrary to the three previous types of HCI, in this type
of interface the statements can be produced in a parallel or sequential manner. This
explains the use of the interleaved parallel operator in the
S
rule. Each statement is
composed of actions that come from a single modality and this is why each statement
in the grammar is indexed by the set
Am
i
, made up of the interactive actions produced
by modality
m
i
. In this type of HCI, the use of two actions at the same time is
not tolerated. This justifies the absence of the parallel operator in the
S
rule of the
