[racket] Typed Racket: Command-line parsing problems

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Mon Jun 24 08:21:27 EDT 2013

On Jun 23, 2013, at 8:34 PM, Sam Tobin-Hochstadt wrote:

>> After porting nearly everything I was left with typing up the command-line
>> parser. However, I am getting a type error at the following simplified part:
> Here's a version that type checks: https://gist.github.com/samth/5847063
> The key is giving a type annotation to `fname` using the #{} syntax.
> Typed Racket can figure out how to typecheck the expansion only if you
> give it that hint.  And the #{} syntax is for adding such hints with
> macros like `command-line` that didn't anticipate Typed Racket.

I think this answer is not fair. 


On Jun 23, 2013, at 2:21 PM, Tim K. wrote:

> I wonder, why does fname have the "Any" type? Yes, I didn't explicitly give 
> fname a type, but I was hoping that the typed version of "command-line" 
> would do that 

is correct. command-line in a typed context should know that what flows into 
its world is a string. 

Posted on the users mailing list.