Intrinsic Functions

The AWS CloudFormation lexicon provides 13 intrinsic functions.

Tag? shows how an intrinsic is authored: a genuine tagged template (Sub\…`) or a plain function call (Ref(…)). **Folds?** shows whether [folding](/chant/concepts/typescript-as-data/#folded-vs-run) — the default chant build path — can reduce a use of this intrinsic today, without running the file — generated directly from this lexicon's registration, not restated by hand. A tagged template folds once it is registered. A plain call folds only where this lexicon has opted that intrinsic in one at a time (foldsAsCall), so a No` in this column means this intrinsic has not been opted in, not that calls in general cannot fold.

Function	Description	Output Key	Tag?	Folds?
Sub	Fn::Sub template string interpolation	Fn::Sub	Yes	Yes
Ref	Reference a parameter or resource	Ref	No	Yes
GetAtt	Fn::GetAtt — get resource attribute	Fn::GetAtt	No	Yes
If	Fn::If — conditional value	Fn::If	No	Yes
Join	Fn::Join — join values with delimiter	Fn::Join	No	Yes
Select	Fn::Select — select value by index	Fn::Select	No	Yes
Split	Fn::Split — split string by delimiter	Fn::Split	No	Yes
Base64	Fn::Base64 — encode to Base64	Fn::Base64	No	Yes
GetAZs	Fn::GetAZs — list Availability Zones	Fn::GetAZs	No	Yes
Equals	Fn::Equals — condition comparing two values	Fn::Equals	No	Yes
And	Fn::And — condition conjunction	Fn::And	No	Yes
Or	Fn::Or — condition disjunction	Fn::Or	No	Yes
Not	Fn::Not — condition negation	Fn::Not	No	Yes