I got the following function from the tutorial and changed it slightly:
inline def power(x: Double, inline n: Int): Double =
inline if (n == 0)
then
1.0
else inline if (n % 2 == 1)
then
x * power(x, n - 1)
// val next = n - 1
// x * power(x, next)
else
power(x * x, n / 2)
As shown above, the code compiles and executes. However, if I replace the x * power(x, n - 1) with the commented lines, I get the error listed below.
Isn’t the assignment equivalent? Both use the same subtraction operation.
TIA
[error] 122 | power(2,2)
[error] | ^^^^^^^^^^
[error] |Cannot reduce `inline if` because its condition is not a constant value: next.==(0)
[error] |---------------------------------------------------------------------------
[error] |Inline stack trace
[error] |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error] |This location contains code that was inlined from Data4.scala:96
[error] 96 | inline if (n == 0)
[error] | ^
[error] 97 | then
[error] 98 | 1.0
[error] 99 | else inline if (n % 2 == 1)
[error] 100 | then
[error] 101 | //x * power(x, n - 1)
[error] 102 | val next = n - 1
[error] 103 | x * power(x, next)
[error] 104 | else
[error] 105 | power(x * x, n / 2)
[error] |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error] |This location contains code that was inlined from Data4.scala:96
[error] 103 | x * power(x, next)
[error] | ^^^^^^^^^^^^^^
[error] |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error] |This location contains code that was inlined from Data4.scala:96
[error] 105 | power(x * x, n / 2)
[error] | ^^^^^^^^^^^^^^^^^^^
[error] ---------------------------------------------------------------------------
[error] one error found