Macros and Extensions

A custom resource runs code during a deployment; a macro runs code before it, on the template itself. You have used one already: AWS 24 ::LanguageExtensions in Fn::ForEach is a macro that AWS hosts, as are AWS::Include and SAM 24 's AWS::Serverless. This section writes one for BookNest.

Subsections

• What Macros Do
• Writing Macros
• LanguageExtensions
• ForEach and ToJsonString
• SAM's Transform