====How Stack-Based Languages Work====

===Introduction===

AQL uses a **stack** when creating queries.

A stack is simply an ordered list of items. Your query will create a stack and return its contents.

When you build your AQL query, you add **data** and **commands** to the stack. 

Each command will usually take one or more //parameters//. For example, the **ASSET** command takes the name of the asset you want to search for as a parameter.

Unlike many programming languages, where your parameters come //after// the command, in a stack-based language, they come //before//.

We will walk you through a quick example of what is going on behind-the-scenes over the next couple of pages, starting with the following small script - **'TE101' ASSET**, which means 'Find the asset with an ID of 'TE101'.

[[stack_example_a|Example Page 1]]