function construction - Passing unquoted strings (poor man's enumeration)

I would like to be able to pass an unquoted string as a parameter to a Mathematica function [that I am writing] and have it show up without evaluation if the string happens to be defined. Thus I would like

Clear["Global`*"]
f[x_] := Print[ToString[x]];
f[Middle] (* prints the string Middle *)
Middle = 3
f[Middle] (* prints the string Middle *)

Obviously this cannot work the way I've written it. Yet it is legal to write

Plot[g[x],{x,0,3}, PlotStyle->Black]

and Black happens to be a protected variable, so it will never be defined.

How can I emulate, or come close to emulating, this behavior. I'm willing to put up with some compromises in the function invocation syntax (in particular, the option syntax opt->Middle would be fine).

Apologies if this is somewhere in the docs. I couldn't find it...

Thanks.

Addendum: While J.M.'s solution answers the question I posed above, I would also like the following to work:

Clear["Global`*"]
SetAttributes[foo,HoldAll];
foo[x_] := Print[ToString[Unevaluated[x]]];

Table[foo[i],{i,{a,b,c}}] (* prints {i,i,i}, as expected *)
Table[foo[Evaluate[i]], {i,{a,b,c}}] (* prints {a,b,c} as expected *)
a = 3
Table[foo[Evaluate[i]], {i,{a,b,c}}] (* prints {3,b,c} *)

I would like the last line to print {a,b,c} just like the one before it - that is, I'd like i evaluated only once. Am I asking too much?

For context: this is part of a larger function that computes something, but does so in different ways depending on the setting of a mode parameter. I want to be able to pass in that mode parameter without evaluation; hence the original question. But I also want to be able to invoke the function inside a Table function as above. Here's a simple example:

Clear["Global`*"]
SetAttributes[foo,HoldAll];
foo[x_] := Block[{z=ToString[Unevaluated[x]]}, If[x == "square", x^2, x+1]];

Table[Integrate[foo[Evaluate[i]],{x,0,3}],{i,{"square", "xyzzy"}}];
    {9, 45/2}
a=3
Table[Integrate[foo[Evaluate[i]],{x,0,3}],{i,{"square", "xyzzy"}}];
    {45/2, 45/2}

since in the second invocation the parameter to foo has the value 3, not the value a. How can I achieve both of these behaviors?

Answer

This seems to work:

SetAttributes[f, HoldAll];

f[x_] := Print[ToString[Unevaluated[x]]]

Now, try Middle = 3; f[Middle].