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> For full documentation content, see https://docs.nvidia.com/nemo/guardrails/llms-full.txt.
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# Colang 2.0 Language Reference

> Reference documentation for Colang 2.0 syntax, events, actions, flows, variables, and the standard library.

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Understand Colang 2.0 concepts and basic syntax.

Learn how Colang generates and matches events.

Use actions and action events in Colang.

Define, start, await, and compose flows.

Use variables and expressions in Colang.

Use branching, loops, and return or abort statements.

Use the Colang Standard Library modules.

Configure and use LLM-related features.

Explore advanced flow behavior and conflict resolution.

Call custom Python actions from Colang.

Debug Colang flows and inspect runtime state.

This chapter is a comprehensive introduction to Colang, explaining all important concepts in a bottom up approach.

* [Introduction](introduction#reference_introduction)
* [Event Generation & Matching](event-generation-and-matching#event-generation-and-matching)
* [Working with Actions](working-with-actions#working-with-actions)
* [Defining Flows](defining-flows#defining-flows)
* [Working with Variables & Expressions](working-with-variables-and-expressions#working-with-variables-and-expressions)
* [Flow control](flow-control#flow-control)
* [Colang Standard Library (CSL)](the-standard-library#the-standard-library)
* [Make use of Large Language Models (LLM)](make-use-of-llms#make-use-of-llms)
* [More on Flows](more-on-flows#more-on-flows)
* [Python Actions](python-actions#python-actions)
* [Development and Debugging](development-and-debugging#development-and-debugging)