stxparse-info/README.md
2021-04-04 07:23:04 +01:00

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stxparse-info

The module stxparse-info/parse is a patched version of syntax/parse which tracks which syntax pattern variables are bound. This allows some libraries to change the way syntax pattern variables work.

For example, phc-graph/subtemplate automatically derives temporary identifiers when a template contains yᵢ …, and xᵢ is a pattern variable. To know from which varᵢ the yᵢ … identifiers must be derived, phc-graph/subtemplate needs to know which syntax pattern variables are within scope.

To use this package, simply require stxparse-info/pares instead of syntax/parse Additionally, it is possible to use the for-syntax function (current-pvars) from stxparse-info/current-pvars to access the list of currently-bound pattern variables, and the macro (with-pvars (pvar ...) . body) can be used to add new pattern variables to the list.