# Parameters {% hint style="info" %} Parameters are an advanced subject that is only relevant to users who frequently have to draft complex clauses & documents. {% endhint %} Parameters are a tool that can be used in Clause9 grammar to make the use of [snippets](https://help.clause9.com/clauses/snippets) even more flexible. They function as a kind of placeholder. Whereas snippets already enable you to replace a piece of text that is used multiple times across a clause or across several clauses/documents, combining snippets with parameters further upgrades the re-usability of a snippet by enabling you to replace the placeholder(s) in a snippet with different input each time you use the snippet. ## How to use parameters ### Insert the parameter as a placeholder in a snippet Parameters are written starting with a question mark, followed by a name of your choice in all caps. For example: `?NAME` or `?TYPE`. Written as such, the parameter should be used in the (internal or external) snippet as a placeholder for input that can be chosen elsewhere (i.e. where the snippet itself is being referenced). ### Give the parameter a value in the snippet reference Without a value, the parameter in the snippet itself will give an error message (the name of the parameter surrounded with a purple background). So to be of any use, it should be assigned a value. That is done in the snippet reference. The grammar for this is as follows: insert the snippet reference, followed by left parenthesis `(`. Insert the name of the (first) parameter. To assign it a value, insert `:=` followed by the relevant value. Multiple parameters can be assigned a value in one snippet reference by separating them with a comma. Close the reference off with right parenthesis `)`. The result looks like this: * for an **internal snippet**: `@SNIPPET-REFERENCE(?PARAMETER1 := value1, ?PARAMETER2 := value2)` * for an **external snippet**: `@#snippet-reference(?PARAMETER1 := value1, ?PARAMETER2 := value2)` (The only difference between these references is the way internal and external snippets themselves are referenced) ### Types of values The parameter can get nearly any value that results in a piece of text. The most important limitations are that a parameter value itself cannot be (i) plain text or (ii) a condition (however, note that use of the `@if` [special function](https://help.clause9.com/special-functions) is allowed). Examples of values: * a concept reference * a datafield * a special function ## Example An example of a very simple notice clause will illustrate this:

Example of the use of parameters with an internal snippet.