command working in command line but cannot generalize as function

In this question

@SiegeX gives a nice way of cleaning the bash PATH variable from duplicate entr开发者_Python百科ies:

PATH=$(awk 'BEGIN{ORS=":";RS="[:\n]"}!a[$0]++' <<<"${PATH%:}")

this works well when I type it in the command line. I tried using this in a bash function to be able to apply it to other variables:

function dupremove()
{
  ${1}=$(awk 'BEGIN{ORS=":";RS="[:\n]"}!a[$0]++' <<<"${1%:}")
}

but when I execute it it gives the error:

> dupremove PATH
bash: PATH=PATH:: command not found

Any idea on I can write the function?

---

This works for me (TM)

function dupremove
{
  eval path=\$$1
  export $1=$(awk 'BEGIN{ORS=":";RS="[:\n]"}!a[$0]++' <<< $path)
}