[racket-dev] [plt] Push #28684: master branch updated

On Tue, May 6, 2014 at 3:30 PM, Neil Toronto <neil.toronto at gmail.com> wrote:
> On 05/06/2014 12:17 PM, samth at racket-lang.org wrote:
>>
>> samth has updated `master' from ad8d0629f8 to 6567ebff59.
>>    http://git.racket-lang.org/plt/ad8d0629f8..6567ebff59
>>
>> =====[ 6 Commits ]======================================================
>> Directory summary:
>>    70.7% pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/
>>     8.3% pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/rep/
>>     4.6% pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/typecheck/
>>     3.2% pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/utils/
>>     3.3% pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/
>>     7.3%
>> pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/
>>
>> ~~~~~~~~~~
>>
>> f83950f Sam Tobin-Hochstadt <samth at cs.indiana.edu> 2014-05-05 21:30
>> :
>> | Refactor type inference to eliminate exceptions.
>> |
>> | This provides approximately 6% speedup on
>> | `racket -l math/scribblings/math.scrbl` and about
>> | 14% speedup on the `new-metrics` test.
>> |
>> | Mostly this involves threading #f through the whole
>> | of the inference process.  There are several new
>> | macros in `typed-racket/infer/fail` which are useful
>> | for comprehensively using Maybe-monad style
>> | programming in Racket.  Of particular note is `%`,
>> | which satisfies (% f e ...) => (and e ... (f e ...))
>> | but with the obvious fixes.
>> |
>> | This commit also weakens several contracts which
>> | caused the build of DrRacket and/or `math` to fail
>> | when contracts were enabled.
>
>
> This is great. Two questions. Why is the math *documentation* a good test
> for the new monadic-style encoding of inference algorithms? (Because it
> tries to evaluate expressions that fail to type?)

Because it's a program that spends a lot of time in typechecking.
This change speeds up typechecking generally, not just when it fails.

> Also, does the last
> paragraph refer to using contracts within TR programs, or to using contracts
> within the implementation of TR?

The latter.

Sam