You can use the command "var !dist cons dist p1 to p3" and then you'll have the result in the variable !dist.
define function !!getDist(!pos1 is POSITION, !pos2 is POSITION) is STRING
var !dist cons dist $!pos1 to $!pos2
return !dist
endfunction
pml rehash all
!col2 = !selection.EVALUATE(OBJECT BLOCK('!!getDist(!selection[!EVALINDEX].dbref().PPos[1],!selection[!EVALINDEX].dbref().PPos[3])'))
define function !!getDist(!pos1 is POSITION, !pos2 is POSITION) is STRING
var !dist cons dist $!pos1 to $!pos2
return !dist
endfunction
pml rehash all
!col2 = !selection.EVALUATE(OBJECT BLOCK('!!getDist(!selection[!EVALINDEX].dbref().PPos[1],!selection[!EVALINDEX].dbref().PPos[3])'))