Re: [racket-users] Catching syntax errors

[Ryan Culpepper]

Use `convert-syntax-error` from the `syntax/macro-testing` module: 
http://docs.racket-lang.org/syntax/macro-testing.html#(form._((lib._syntax%2Fmacro-testing..rkt)._convert-syntax-error))


Ryan


On 06/30/2017 04:47 PM, Sam Waxman wrote:

Hello,

I'm trying to test whether or not certain programs result in syntax errors. For 
example the program

#lang racket
a

will result in an unbound identifier error, even before runtime (you'll see the 
little error message at the bottom because it errored in phase 1).

I know how to catch runtime errors, but I haven't been able to catch these 
expansion time errors as of yet. I've tried doing roughly the same thing as 
catching runtime errors, but with begin-for-syntax, but it hasn't been working 
out for me.

Ideally, I want a macro like

(return-syntax-error stuff-to-expand ...)

that will run stuff-to-expand, and if runs into a syntax error, for it to be caught and 
returned (as the error struct #).

Any tips?

Many thanks in advance.



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Re: [racket-users] Catching syntax errors

[Philip McGrath]

If testing with parenthetical syntax is sufficient, you might want
something like this:

#lang racket

(with-handlers ([exn:fail:syntax? values])
  (eval `(module bad racket (define foo (define bar 1)))
(make-base-namespace)))

which returns:

(exn:fail:syntax
 "define: not allowed in an expression context"
 #
 '(.#))







-Philip

On Fri, Jun 30, 2017 at 3:47 PM, Sam Waxman  wrote:

> Hello,
>
> I'm trying to test whether or not certain programs result in syntax
> errors. For example the program
>
> #lang racket
> a
>
> will result in an unbound identifier error, even before runtime (you'll
> see the little error message at the bottom because it errored in phase 1).
>
> I know how to catch runtime errors, but I haven't been able to catch these
> expansion time errors as of yet. I've tried doing roughly the same thing as
> catching runtime errors, but with begin-for-syntax, but it hasn't been
> working out for me.
>
> Ideally, I want a macro like
>
> (return-syntax-error stuff-to-expand ...)
>
> that will run stuff-to-expand, and if runs into a syntax error, for it to
> be caught and returned (as the error struct # #).
>
> Any tips?
>
> Many thanks in advance.
>
> --
> You received this message because you are subscribed to the Google Groups
> "Racket Users" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to racket-users+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
>

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[racket-users] Catching syntax errors

[Sam Waxman]

Hello,

I'm trying to test whether or not certain programs result in syntax errors. For 
example the program

#lang racket
a

will result in an unbound identifier error, even before runtime (you'll see the 
little error message at the bottom because it errored in phase 1).

I know how to catch runtime errors, but I haven't been able to catch these 
expansion time errors as of yet. I've tried doing roughly the same thing as 
catching runtime errors, but with begin-for-syntax, but it hasn't been working 
out for me.

Ideally, I want a macro like

(return-syntax-error stuff-to-expand ...)

that will run stuff-to-expand, and if runs into a syntax error, for it to be 
caught and returned (as the error struct #).

Any tips?

Many thanks in advance.

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