49 lines
1.4 KiB
Text
49 lines
1.4 KiB
Text
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TODO
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Support:
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1. Create Racket version of the nanopass framework
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2. Extended to more R6RS libraries (at least if they support some form of
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compile time environment).
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Nanopass Annoyances:
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1. Removal of patterns is too strict matching EXACTLY the variable names (see
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above example) This may not be bad, but without the error is a very rough
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edge.
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2. Output forms need to match original language forms very closely, e.g. if we
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have:
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(define-language L
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over
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---
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where
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(e in Expr
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(begin e0 ... e1)
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---)
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---)
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we cannot create the constructor:
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`(begin (set! ,x0 (var ,tmp*)) ...)
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because it sees this as a single form instead of a list. Being able to
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create a make-begin helper for this situation is helpful, but ultimately
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we'd like it to match broader forms and complain at compilation time if it
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cannot prove they are safe itself. The contortion we are instead forced to
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perform is:
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(let* ([expr* (map (lambda (x tmp) `(set! ,x (var ,tmp))) x0 tmp*)]
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[rexpr* (reverse expr*)]
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[last-expr (car rexpr*)]
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[expr* (reverse (cdr expr*))])
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`(begin ,expr* ... ,last-expr))
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Features to add down the road:
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1. Pass fusing with deforestation of the intermediate passes.
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Error Handling/Loosening restrictions:
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1. Fix parser to use positional information to report errors on the syntax
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error, in addition to reporting the error.
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