 
 
 
5.37.2  Boundaries of an interval : left right
 
left (resp. right) takes as argument an interval.
left (resp. right) returns the left (resp. right) boundary
of this interval. 
Note that .. is an infixed operator, therefore:
- 
sommet(1..5) is equal to ’..’ and feuille(1..5)
is equal to (1,5).
- the name of the interval followed by 
[0] returns the operator ..
- the name of the interval followed by [1] 
(or the left command) returns the left boundary.
- The name of the interval followed by [2] 
(or the right command) 
returns the right boundary.
Input :
(3..5)[0]
or :
sommet(3..5)
Output :
’..’
Input :
left(3..5)
or :
(3..5)[1]
or :
feuille(3..5)[0]
or :
op(3..5)[0]
Output :
3
Input :
right(3..5)
or :
(2..5)[2]
or :
feuille(3..5)[1]
or :
op(3..5)[1]
Output :
5
Remark
left (resp. right) returns also the left (resp. right) member of an 
equation (for example left(2*x+1=x+2) returns 2*x+1).
 
 
