This might get you started:
import std/macros
macro toLets[T](vals: openArray[T], vars: varargs[untyped]): untyped =
result = newStmtList()
for i, v in vars: # change| to const or var
result.add(quote do: (let `v` = `vals`[`i`]))
var fieldList = [1, 2, 3]
fieldList.toLets a, b, c
echo a, b, c
Run
However, it may be even simpler to just define a bunch of names for your column
indices and use that directly. E.g.,
import std/macros
macro mkNums(vars: varargs[untyped]): untyped =
result = newStmtList()
for i, v in vars:
result.add(quote do: (const `v` = `i`))
mkNums first, last, phone
echo first, " ", last, " ", phone
# echo field[last], ",", field[first]
Run
Note that when processing CSV it is more efficient to not create a new
`seq[string]` for each row, but rather iterate over the fields anyway (e.g.
with the `strutils.split` _iterator_ called by `for` not the `proc`).
[This](https://forum.nim-lang.org/t/9688) is the most recent thread on that
topic, but it comes up a lot. So, I thought I might try to get ahead of it. ;-)
If you run into trouble you might do some Forum searches.
You might also look at the code generated by my row processor
[rp](https://github.com/c-blake/bu/blob/main/doc/rp.md) which is a hybrid
approach: reusing the same seq[] object for each row, but still having one so
you can reference `s[last]` (though that assumes your input file has column
headers). You could also preprocess all your data into pre-parsed numeric
binary files if you need to operate over them many times as in
[nio](https://github.com/c-blake/nio) or probably load it into a database and
probably 3 ways I'm neglecting to mention. There are really many ways to skin
these cats... :-) Hopefully some of this helps you.
