You need to use generics.
import tables
proc getTableOf*[T]: ref Table[int, T] =
var table {.global.} = newTable[int, T]()
return table
proc getVal[T](key: int): T =
getTableOf[T]()[key]
getTableOf[bool]()[0] = true
assert getVal[bool](0) == getTableOf[bool]()[0]
assert getVal[bool](0)
proc getMutableVal[T](key: int): var T =
getTableOf[T]()[key]
getTableOf[bool]()[0] = true
assert getVal[bool](0)
getMutableVal[bool](0) = false
assert(not getVal[bool](0))
If you still want to pass a typedesc as an argument, you can use typedesc[T].
import tables
proc getTableOf*[T](desc: typedesc[T]): ref Table[int, T] =
var table {.global.} = newTable[int, T]()
return table
proc getVal[T](key: int, desc: typedesc[T]): T =
getTableOf(T)[key]
getTableOf(bool)[0] = true
assert 0.getVal(bool) == getTableOf(bool)[0]
assert 0.getVal(bool)
proc getMutableVal[T](key: int, desc: typedesc[T]): var T =
getTableOf(T)[key]
getTableOf(bool)[0] = true
assert 0.getVal(bool)
0.getMutableVal(bool) = false
assert(not getVal(0, bool))
Keep in mind you can also turn getVal and getMutableVal into templates instead
of procs to get rid of runtime overhead. Templates don't need type information,
they transform AST into other AST during compile time (from my knowledge at
least).
