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).