RingElement _ Ring -- generator of a ring with a given name

RingElement _ Ring -- generator of a ring with a given name

Synopsis:

Usage: r = x_R

Operator: _

Input:

x, an instance of class RingElement.

R, an instance of class Ring.

Output:

r, an instance of class RingElement: the generator of the ring R whose name is the same as that of x.

Code:

     -- ../../../Macaulay2/m2/ofcm.m2:182-189
     RingElement _ Ring := RingElement => (x,R) -> (
          if ring x === R then x
          else try x * 1_R
          else try (baseName x)_R
          ---- we might enable the line below if map(R,S) would insist on finding every variable
          -- else try (map(R,ring x)) x
          else error "failed to interpret ring element in ring"
          )