In computer science, an abstract syntax tree (AST), or just syntax tree, is a tree representation of the abstract syntactic structure of text (often source code) written in a formal language. Each node of the tree denotes a construct occurring in the text.

In my experience, the ability to work with ASTs helps create dev tools that work like magic. ASTs are heavily used in compilers to generate or transform code. If you wanted to build your own language, the first challenge is to design the grammar for your language (aka a context free grammar). An amazing tool for doing this is ANTLR. ANTLR takes your grammar and generates a parser to parse strings into ASTs. The output AST can then be used however way you want.