Re: [racket] Syntax certificate question
Okay, I don't understand what's going on, but I've fixed the program. First I had to apply the result of (syntax-local-certifier #t) directly to the reference to identity. I don't know why this is. I also had to expand the body of with-macro in the internal definition context I created, so that references to lhs don't escape the expansion of with-macro. That part makes sense to me. #lang racket/load (module A racket (provide with-macro) (require (for-syntax racket/syntax syntax/parse)) (define-for-syntax (identity x) x) (define-syntax with-macro (syntax-parser [(_ lhs:id rhs:expr e:expr) (define ctx (syntax-local-make-definition-context)) (syntax-local-bind-syntaxes (list #'lhs) #`(#,((syntax-local-certifier #t) #'identity) rhs) ctx) (internal-definition-context-seal ctx) (local-expand #'e (list (gensym 'with-macro)) null ctx)]))) (module B racket (require 'A (for-syntax syntax/parse)) (with-macro thunk (syntax-parser [(_ e:expr) #'(lambda () e)]) (thunk (printf "Boo!\n" On Sat, Jun 4, 2011 at 3:13 PM, Carl Eastlund wrote: > A question for the syntax certificate connoisseurs out there. The > program below produces the following error message: > > compile: access from an uncertified context to unexported variable > from module: "A" in: identity > > Why is the reference to identity from within the module that binds it > illegal? Is that syntax object somehow not certified correctly, or > does syntax-local-bind-syntaxes result in some illegal destructuring > of its input? I imagine I can work around this by providing identity > so that the certificate system ignores it, but I'd like to at least > understand what's causing this error. > > #lang racket/load > > (module A racket > (provide with-macro) > (require (for-syntax racket/syntax syntax/parse)) > (define-for-syntax (identity x) x) > (define-syntax with-macro > (syntax-parser > [(_ lhs:id rhs:expr e:expr) > (define ctx (syntax-local-make-definition-context)) > (syntax-local-bind-syntaxes (list #'lhs) #'(identity rhs) ctx) > (internal-definition-context-seal ctx) > (internal-definition-context-apply ctx #'e)]))) > > (module B racket > (require 'A (for-syntax syntax/parse)) > (with-macro thunk (syntax-parser [(_ e:expr) #'(lambda () e)]) > (thunk (printf "Boo!\n" > _ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
Re: [racket] Syntax certificate question
On Sat, Jun 4, 2011 at 3:17 PM, Jay McCarthy wrote: > 2011/6/4 Carl Eastlund : >> A question for the syntax certificate connoisseurs out there. The >> program below produces the following error message: >> >> compile: access from an uncertified context to unexported variable >> from module: "A" in: identity >> >> Why is the reference to identity from within the module that binds it >> illegal? Is that syntax object somehow not certified correctly, or >> does syntax-local-bind-syntaxes result in some illegal destructuring >> of its input? I imagine I can work around this by providing identity >> so that the certificate system ignores it, but I'd like to at least >> understand what's causing this error. >> >> #lang racket/load >> >> (module A racket >> (provide with-macro) >> (require (for-syntax racket/syntax syntax/parse)) >> (define-for-syntax (identity x) x) > > Isn't this a phase 1 binding? Yup. >> (define-syntax with-macro >> (syntax-parser >> [(_ lhs:id rhs:expr e:expr) >> (define ctx (syntax-local-make-definition-context)) >> (syntax-local-bind-syntaxes (list #'lhs) #'(identity rhs) ctx) > > And this a phase -1 (template) use, which normally goes for the phase 0 > binding Nope. The second argument to syntax-local-bind-syntaxes is a compile-time (phase 1) expression. It is essentially equivalent to a syntax definition: (define-syntaxes [lhs] (identity rhs)) >> (internal-definition-context-seal ctx) >> (internal-definition-context-apply ctx #'e)]))) >> >> (module B racket >> (require 'A (for-syntax syntax/parse)) >> (with-macro thunk (syntax-parser [(_ e:expr) #'(lambda () e)]) > > And this is a phase 0 use? > > Is that the problem? Sadly, no. This would be easier to work out if it were a phase problem. The error message clearly says that identity refers to an unexported variable from A. If this were a phase problem, it should instead say that identity is unbound. --Carl _ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
Re: [racket] Syntax certificate question
2011/6/4 Carl Eastlund : > A question for the syntax certificate connoisseurs out there. The > program below produces the following error message: > > compile: access from an uncertified context to unexported variable > from module: "A" in: identity > > Why is the reference to identity from within the module that binds it > illegal? Is that syntax object somehow not certified correctly, or > does syntax-local-bind-syntaxes result in some illegal destructuring > of its input? I imagine I can work around this by providing identity > so that the certificate system ignores it, but I'd like to at least > understand what's causing this error. > > #lang racket/load > > (module A racket > (provide with-macro) > (require (for-syntax racket/syntax syntax/parse)) > (define-for-syntax (identity x) x) Isn't this a phase 1 binding? > (define-syntax with-macro > (syntax-parser > [(_ lhs:id rhs:expr e:expr) > (define ctx (syntax-local-make-definition-context)) > (syntax-local-bind-syntaxes (list #'lhs) #'(identity rhs) ctx) And this a phase -1 (template) use, which normally goes for the phase 0 binding > (internal-definition-context-seal ctx) > (internal-definition-context-apply ctx #'e)]))) > > (module B racket > (require 'A (for-syntax syntax/parse)) > (with-macro thunk (syntax-parser [(_ e:expr) #'(lambda () e)]) And this is a phase 0 use? Is that the problem? Jay > (thunk (printf "Boo!\n" > _ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/users > -- Jay McCarthy Assistant Professor / Brigham Young University http://faculty.cs.byu.edu/~jay "The glory of God is Intelligence" - D&C 93 _ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
