The |parametre_url{variable name, value} filter, applied to a URL type tag (e.g. #SELF, #URL_ARTICLE, #URL_PAGE{sommaire}...), will add or remove a parameter to that URL.
For example:[(#SELF|parametre_url{country, France})] will add to the current page’s URL either ?country=France if it is the first parameter passed in the URL or &country=France if the URL already has at least one other parameter.
Such tags are typically included in the href part of a link definition:
<a href="[(#SELF|parametre_url{country,France})]">France</a>
To then later retrieve the value of the parameter passed in the URL, we would use the #ENV tag.
In the example above, #ENV{var1} would return France.
Passing several parameters with the URL
We can chain filters for passing a series of parameters and their values to a URL: [(#SELF|parametre_url{country,France}|parametre_url{currency,euro})].
If we want to pass the same value to several parameters, we would use this syntax: [(#SELF|parametre_url{country|location|territory, France})] which will return the current page’s URL suffixed with: country=France&location=France&territory=France.
Deleting existing parameters
To make an existing URL parameter disappear, you need to empty it’s value by declaring a new one that is explicitly empty: [(#SELF|parametre_url{country, ''})].
We can delete several parameters at one with: [(#SELF|parametre_url{country|location|territory, ''})].