Given two ranges:

   



[

a

1


,

a

2


]


{\displaystyle [a_{1},a_{2}]}

   and 
   



[

b

1


,

b

2


]


{\displaystyle [b_{1},b_{2}]}

; 
   then a value   



s


{\displaystyle s}

   in range   



[

a

1


,

a

2


]


{\displaystyle [a_{1},a_{2}]}


   is linearly mapped to a value   



t


{\displaystyle t}

   in range   



[

b

1


,

b

2


]


{\displaystyle [b_{1},b_{2}]}


   where:



   



t
=

b

1


+



(
s
−

a

1


)
(

b

2


−

b

1


)


(

a

2


−

a

1


)





{\displaystyle t=b_{1}+{(s-a_{1})(b_{2}-b_{1}) \over (a_{2}-a_{1})}}




Task

Write a function/subroutine/... that takes two ranges and a real number, and returns the mapping of the real number from the first to the second range.

Use this function to map values from the range    [0, 10]    to the range    [-1, 0]. 



Extra credit

Show additional idiomatic ways of performing the mapping, using tools available to the language.




/*REXX program maps and displays a  range of numbers from  one range  to  another range.*/
rangeA =   0   10                                      /*or:   rangeA =   '  0  10 '    */
rangeB =  -1    0                                      /*or:   rangeB =   " -1   0 "    */
parse  var   rangeA  L  H
inc= 1
          do j=L  to H  by inc * (1 - 2 * sign(H<L) )  /*BY:   either   +inc  or  -inc  */
          say right(j, 9)      ' maps to '      mapR(rangeA, rangeB, j)
          end   /*j*/
exit                                                   /*stick a fork in it, we're done.*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
mapR: procedure; parse arg a1 a2,b1 b2,s;$=b1+(s-a1)*(b2-b1)/(a2-a1);return left('',$>=0)$