Frequency dependent capacitor for AC sweep analysis in LTspice
The example you saw in the link you provided makes use of the Laplace transfer function -- the so-called "GLAPLACE", no such thing (at least not in LTspice). Here is an example:



To the right is what's in the link, to the left is what you'd want. As you can see, the inductor (s*L) is nothing more than the reverse of the capacitor (1/(s*C)). The slopes differ because the Laplace transfer functions use sqrt(s).

Word of warning: The Laplace operator should not be used in .TRAN analysis, as it is very prone to errors and instabilities. In .AC it's perfectly fine, and extremely versatile, so you can adapt whichever Laplace transfer function you want. BTW, that's not LTspice code, you probably meant pseudo-code for your needs.

If you intend to do transient analysis, the only solutions you sould be using are the behavioural inductor (its value is of the form Flux=f(x), see the manual for more) but which is sensitive to noise (use with care), or approximate the response with a Cauer or Foster topology (or whichever homegrown network suits you).