seq: optimize append #280
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seq: optimize append #280
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There are two changes in this commit.
The first change builds the list from a variadic append operation
from right to left, which is the natural order for list construction.
This speeds up the following program:
```
(time
(void
(append* (for/list ([i 30000])
(if b '() '(1))))))
```
from 5 seconds to 1 second.
The second change avoids making an assertion when doing unsafe/append
on two symbolic unions. This is fine because all calls to unsafe/append
is already guarded via type casting to make them symbolic unions
of rosette-contract?, so there is no need to add another guard.
Thanks to @camoy for raising up the issue about the unnecessary assertions.
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There are two changes in this commit.
The first change builds the list from a variadic append operation from right to left, which is the natural order for list construction. This speeds up the following program:
from 5 seconds to 1 second.
The second change avoids making an assertion when doing unsafe/append on two symbolic unions. This is fine because all calls to unsafe/append is already guarded via type casting to make them symbolic unions of rosette-contract?, so there is no need to add another guard.
Thanks to @camoy for raising up the issue about the unnecessary assertions.