/*REXX program maps and displays a  range of numbers from  one range  to  another range.*/
rangeA =  10   0                                       /*or:   rangeA =   '  0  10 '    */
rangeB =  -1   0                                       /*or:   rangeB =   " -1   0 "    */
parse  var   rangeA  L  H
inc= 1/2
          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)$