Glossary

A quick reference for the terms used throughout these docs. Most map directly to a macro keyword or a piece of the compiler pipeline.

Core concepts

Actio — A transpiler that compiles a .actio.yml source into standard GitHub Actions workflow YAML. It adds a small set of compile-time macros on top of the normal workflow syntax.

Transpile / compile — The act of expanding macros and resolving compile-time tokens with actio build, producing plain .yml files. Every macro is stripped or expanded; none survive into the output.

Superset — Actio is a strict superset of GitHub Actions workflow syntax. Every standard key, event, and value works exactly as it does in a normal workflow, so a macro-free .actio.yml file is a normal workflow.

Macro — A keyword Actio adds on top of normal workflow syntax that expands into the boilerplate GitHub requires. See the syntax reference for the full list.

Pass — A single transform step in the compiler pipeline. Built-in passes implement the macros; you can register custom passes that are merged into the pipeline and ordered by their runsAfter dependencies.

Drift check — actio check (alias for build --check): verifies the committed workflows match what the sources would generate, failing CI if they're stale.

Executor — A named runner/container/service preset declared under executors. A job selects one (or an ordered list) via executor, and Actio merges its runs-on/container/services in at compile time.

Hoist — Moving an untrusted ${{ }} context value out of a run: body into env: and referencing it by variable, so it can't be executed as part of the shell command. This is the script-injection mitigation that injection-hoist performs.

Interpolation

Compile-time token — {{ ... }}. Resolved by actio build and baked into the output (e.g. {{ params.env }}, {{ toJSON(params.matrix) }}).

Runtime passthrough — ${{ ... }}. Emitted verbatim for the GitHub Actions runner to evaluate at run time.

Macro keywords

Actio adds roughly nineteen macro keywords. Rather than re-list them here, see the syntax reference for the complete keyword dictionary and the macro guides for tutorial-style walkthroughs of each one.

Output

Target profile — The output flavor selected with --target: legacy (default) or github-actions-native-dependencies-preview.

Source map — A .yml.map file written beside each generated workflow that maps generated lines back to the .actio.yml source. See source maps.

Header banner — The generated-by-Actio comment stamped at the top of each output file (suppress with --no-header).

Modeline — An editor hint comment that opts a file into Actio's JSON Schema for autocomplete. See editor support.