3.2 BNF syntax notation

The grouping implied the abbreviations used the regular expression description in Table 1 and previously visualised as a tree can easily be generalised as a context-free language and expressed in terms of a context-free grammar in BNF notation (see Table 2, Hopcroft and Ullman (1979)).

Table 2: CoGesT 1.1 BNF syntax.

$<$cogest$>$	$\rightarrow$	$<$complexgesture$>$
$<$complexgesture$>$	$\rightarrow$	$<$gesturepair$>$[$<$complexgesture$>$]
$<$gesturepair$>$	$\rightarrow$	$<$simplexgesture$>$$<$simplexgesture$>$
$<$simplexgesture$>$	$\rightarrow$	$<$source$>$[$<$route$>$]
$<$source$>$	$\rightarrow$	$<$location$>$$<$handshape$>$
$<$route$>$	$\rightarrow$	$<$direction$>$ ($<$trajectoryshape$>$ $\mid$ $<$microgesture$>$) $<$trajectoryhandshape$>$ $<$trajectorysize$>$ $<$trajectoryspeed$>$$<$target$>$
$<$microgesture$>$	$\rightarrow$	$<$source$>$$<$route$>$[$<$microgesture$>$]
$<$direction$>$	$\rightarrow$	$<$lateral$>$$<$sagital$>$$<$vertical$>$
$<$lateral$>$	$\rightarrow$	ri $\mid$ le $\mid$ NULL $\mid$ ?
$<$sagital$>$	$\rightarrow$	fo $\mid$ ba $\mid$ NULL $\mid$ ?
$<$vertical$>$	$\rightarrow$	up $\mid$ do $\mid$ NULL $\mid$ ?
$<$trajectoryshape$>$	$\rightarrow$	ci $\mid$ li $\mid$ wl $\mid$ ar $\mid$ zl $\mid$ el $\mid$ sq $\mid$ ?
$<$trajectoryhandshape$>$	$\rightarrow$	$<$handshape$>$
$<$trajectorysize$>$	$\rightarrow$	xs $\mid$ s $\mid$ m $\mid$ l $\mid$ xl $\mid$ ?
$<$trajectoryspeed$>$	$\rightarrow$	sl $\mid$ fa $\mid$ me $\mid$ ?
$<$target$>$	$\rightarrow$	$<$location$>$$<$handshape$>$
$<$location$>$	$\rightarrow$	$<$height$>$$<$verticalpos$>$
$<$height$>$	$\rightarrow$	1 $\mid$ 2 $\mid$ 3 $\mid$ 4 $\mid$ 5 $\mid$ 6 $\mid$ 7 $\mid$ 8 $\mid$ 9 $\mid$ 10 $\mid$ 11 $\mid$ 12 $\mid$ 13 $\mid$ 14 $\mid$ 15 $\mid$ 16 $\mid$ 17 $\mid$ 18 $\mid$ 19 $\mid$ ?
$<$verticalpos$>$	$\rightarrow$	ll $\mid$ l $\mid$ m $\mid$ r $\mid$ rr $\mid$ ?
$<$handshape$>$	$\rightarrow$	0A $\mid$ 1A $\mid$ 2A $\mid$ 3A $\mid$ 4A $\mid$ 5A $\mid$ 6A $\mid$ 0B $\mid$ 1B $\mid$ 2B $\mid$ 3B $\mid$ 5B $\mid$ 6B $\mid$ 0C $\mid$ 1C $\mid$ 2C $\mid$ 3C $\mid$ 5C $\mid$ 6C $\mid$ 0D $\mid$ 1D $\mid$ 2D $\mid$ 3D $\mid$ 5D $\mid$ 6D $\mid$ 0E $\mid$ 1E $\mid$ 2E $\mid$ 3E $\mid$ 5E $\mid$ 6E $\mid$ 0F $\mid$ 1F $\mid$ 2F $\mid$ 3F $\mid$ 5F $\mid$ 6F $\mid$ 1G $\mid$ 2G $\mid$ 5G $\mid$ 6G $\mid$ 5H $\mid$ 6H $\mid$ 2I $\mid$ 5I $\mid$ 6I $\mid$ 2J $\mid$ 2K $\mid$ 7A $\mid$ ?