Re: [racket-users] how to match unbound identifier as literal in `syntax-parse`?

> On Apr 3, 2018, at 4:37 AM, Ryan Culpepper wrote: > > Here's one way: > > (~and z:id > (~fail #:unless (free-identifier=? #'z #'zeta) > "expected the identifier `zeta`")) > > Another way is to make a syntax class (either specifically for `zeta` or >

Re: [racket-users] let-syntax example?

> On Apr 3, 2018, at 2:31 PM, Kevin Forchione wrote: > > Hi Guys, > Does anyone have an analogous example for let-syntax to something as simple > as this? > > (let ([a 3]) a) > > Something like…. > > (let-syntax ([a 3]) ….) > > At which point I’m stumped as

Re: [racket-users] let-syntax example?

On Tue, Apr 3, 2018 at 3:02 PM, Shu-Hung You wrote: > Hi Keven, > > Here's an example: > > #lang racket > (let-syntax ([a (lambda (stx) >(printf "expansion time: stx = ~a\n" stx) >#'3) ]) > a) > >

Re: [racket-users] let-syntax example?

Hi Keven, Here's an example: #lang racket (let-syntax ([a (lambda (stx) (printf "expansion time: stx = ~a\n" stx) #'3) ]) a) However, I would suggest to start at least from syntax objects and macro transformers in the guide and use

[racket-users] let-syntax example?

Hi Guys, Does anyone have an analogous example for let-syntax to something as simple as this? (let ([a 3]) a) Something like…. (let-syntax ([a 3]) ….) At which point I’m stumped as to what expression in the body would return 3. There are no examples in the Reference.

Re: [racket-users] how to match unbound identifier as literal in `syntax-parse`?

Here's one way: (~and z:id (~fail #:unless (free-identifier=? #'z #'zeta) "expected the identifier `zeta`")) Another way is to make a syntax class (either specifically for `zeta` or parameterized by the identifier) that does the same check. Ryan On 4/3/18 8:33 AM,

Re: [racket-users] Why is there a space in the path to the Racket application on MacOSX?

One way the student languages from HtDP are different from most Racket DSLs and langs is that, in the service of regularity and nice error messages, they take away many convenient and powerful features of the full Racket language. There is not really an "escape hatch" into full Racket, other than

[racket-users] how to match unbound identifier as literal in `syntax-parse`?

Consider the difference in results below. How would I persuade `syntax-parse` to match literal identifiers in the `free-identifier=?` sense that `syntax-case` does? (and thereby allow unbound identifiers to be compared also) IIUC, `#:literals` is too strict, as it insists that every listed