How to define a function inside a module through Evaluate [duplicate]

Question

I am trying to define a function inside a module as following

test1[a_] := Module[{sol1, g1, y}, sol1 = Reduce[a + x^2 == y, x]; g1[y_] := Evaluate@sol1[[1, -1]]; Print[Definition[g1]]; g1[33] ]

This gives the output

Attributes[g1$28580]={Temporary} g1$28580[y$_]:=-Sqrt[-3+y$28580] -Sqrt[-3 + y$28588]

As you can see this does not work. The y in the body of the function is y$28580, but not y$. Is there any way to make this work?

If you use Block instead of Module does that solve the problem? — Jason B.
– Jason B., Commented Nov 30, 2018 at 19:09
Use this: SetDelayed @@ {g1[y_], sol1[[1, -1]]} and read this: Enforcing correct variable bindings — Kuba
– Kuba, Commented Nov 30, 2018 at 21:31

Wen Chern · Accepted Answer · 2018-11-30 20:03:52Z

1

Just replace the third line by:

g1[Pattern[Evaluate[y], _]] = sol1[[1, -1]];

answered Nov 30, 2018 at 20:03

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