Tracking bound syntax pattern variables with syntax-parse
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 ofsyntax/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.