Unfortunately, that is not that simple...
Like I said in the introduction, the templates are generated by another
template. So the real code of my project looks like:
template generate(op: untyped, Typ1, Typ2, Tout: untyped) =
template `op`(a: `Typ1`, b: typed): `Tout` =
when typeof(b) isnot `Typ2`:
{.error: "Second param " & astToStr(b) & " of == with Real is not a
float, but is " & $typeof(b).}
a.val == b
template `op`(a: typed, b: `Typ1`): `Tout` =
when typeof(a) isnot `Typ2`:
{.error: "First param " & astToStr(b) & " of == with Real is not a
float, but is " & $typeof(b).}
a == b.val
# Generate operators for all types
generate(`==`, Real, float, bool)
etc.
...
Run
Now the when code executes when **I** compile my module while generating the
templates for all operators x types, and it aborts compilation (with a cryptic
error message like Type expected: got bool or Error: type expected, but got
symbol 'bool' of kind 'Template' if I change is not for isnot in the module
code!)
Instead, it should happen when **the user** compiles his code with invalid
parameters.
At least, that's how I interpret what's happening. The bug occurs only when I
have the 2 lines in the generated templates:
when typeof(b) isnot `Typ2`:
{.error: "Second param " & astToStr(b) & " of == with Real is not a
float, but is " &
Run
But there must be another real reason because when I try with all the other
types, I don't get the problem; only with the bool parameter. I spent too much
time today on that bug to have a clear vision. At some time during the day,
when I tried different forms of the code, I got [the same
error](https://forum.nim-lang.org/t/3497), but now with Nim 1.2.0 the error has
changed...
Perhaps it's time to convert this template to a macro and learn how to inject
the when ... lines?
