6.10.2.4 Further Information

For a formal definition of syntax-rules and its pattern language, see See Macros in Revised(5) Report on the Algorithmic Language Scheme.

syntax-rules macros are simple and clean, but do they have limitations. They do not lend themselves to expressive error messages: patterns either match or they don’t. Their ability to generate code is limited to template-driven expansion; often one needs to define a number of helper macros to get real work done. Sometimes one wants to introduce a binding into the lexical context of the generated code; this is impossible with syntax-rules. Relatedly, they cannot programmatically generate identifiers.

The solution to all of these problems is to use syntax-case if you need its features. But if for some reason you’re stuck with syntax-rules, you might enjoy Joe Marshall’s syntax-rules Primer for the Merely Eccentric.

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