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Use front-end/interactions to perform the language require if there

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was a syntax error in the module.  This means that things are a little
odd: we only try to require the language after the user hits enter.  A
solution might be for drscheme to always call the
front-end/interactions method immediately on an empty input port.

svn: r11079
This commit is contained in:
Eli Barzilay 2008-08-05 13:35:01 +00:00
parent 12390fb891
commit ee2a6f7ceb
1 changed files with 27 additions and 29 deletions
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56
collects/drscheme/private/module-language.ss
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@ -152,9 +152,28 @@
(define hopeless-repl (make-thread-cell #t))
(define/override (front-end/interaction port settings)
(if (thread-cell-ref hopeless-repl)
(raise-hopeless-syntax-error)
(super front-end/interaction port settings)))
(let ([x (thread-cell-ref hopeless-repl)])
(cond
[(not x) (super front-end/interaction port settings)]
[(not (syntax? x)) (raise-hopeless-syntax-error)]
;; this means that there was a problem getting into the
;; module's namespace, and we have a language to try to require
[else
(let ([default-handler (uncaught-exception-handler)])
(expr-getter (super front-end/interaction port settings)
#`(current-module-declare-name #f)
(λ ()
(uncaught-exception-handler
(λ (e)
(uncaught-exception-handler default-handler)
(raise-hopeless-syntax-error "invalid language" x))))
#`(require #,x)
(λ ()
(uncaught-exception-handler default-handler)
(unless (memq '#%top-interaction (namespace-mapped-symbols))
(raise-hopeless-syntax-error
"invalid language (existing module, but no language bindings)"
x)))))])))
;; This is used to setup the user environment. There's a subtle hack
;; here: instead of doing things like (namespace-require ...), construct
@ -186,36 +205,15 @@
;; check syntax doesn't think the original module name is being
;; used in this require (so it doesn't get turned red)
(quasisyntax ''#,(datum->syntax #'here (syntax-e name)))))
(define default-handler (uncaught-exception-handler))
(define ns (current-namespace))
;; we have a language, so put it here, so front-end/interaction can
;; require the language if we fail to go into the module -- most
;; commonly due to a syntax error, in attempt to still provide a
;; working repl
(thread-cell-set! hopeless-repl lang)
(expr-getter (λ () eof)
#`(current-module-declare-name
(and #,path (make-resolved-module-path '#,path)))
;; We now need to send the module definition, but that might lead to
;; syntax errors, so set an exception handler first -- if there's an
;; error, try to require the language module in so we're left with a
;; working repl. Also check that there's a `#%top-interaction'
;; binding, and barf if not, since it's most likely a mistake of using
;; a plain module as a language.
(λ ()
(uncaught-exception-handler
(λ (e)
(define e1 #f)
(uncaught-exception-handler default-handler)
;; use this to catch the error so it can be raised instead of e
(with-handlers ([void (lambda (e) (set! e1 e))])
(parameterize ([current-namespace ns])
(with-handlers ([void (λ (e) (raise-hopeless-syntax-error
"invalid language" lang))])
(namespace-require (syntax->datum lang)))
(unless (memq '#%top-interaction (namespace-mapped-symbols ns))
(raise-hopeless-syntax-error
"invalid language (existing module, but no language bindings)"
lang))))
(thread-cell-set! hopeless-repl #f)
(default-handler (or e1 e)))))
module-expr
(λ () (uncaught-exception-handler default-handler)) ; restore handler
#`(current-module-declare-name #f)
(if path
#`(#%app (#%app current-module-name-resolver)