# Reference ## Core - [Defining grammars using objects](objectDefs.md) - [Defining grammars using strings](stringDefs.md) - [Whitespace handling](whitespace.md) - [Skipping](skipping.md) junk within matches - [Computed fields and validation functions](functions.md) - [Provided matchers](providedMatchers.md) ## Advanced - [Handling circular references](circularity.md) via lazy matchers - Implementing [custom matchers](customMatchers.md) - Maintaining [state](state.md) while matching 1. - [Troubleshooting](trouble.md) tips - [Performance](performance.md) tips