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;;; test-lr-error-recovery-02.scm --
;;
;;Test error recovery policy when the synchronisation terminal has the
;;same category of the lookahead that raises the error.
;;
(load "common-test.scm")
(define (doit . tokens)
(let ((parser (lalr-parser (expect: 0)
(A B C)
(alphas (alpha) : $1
(alphas alpha) : $2)
(alpha (A B) : (list $1 $2)
(C) : $1
(error C) : 'error-form))))
(parser (make-lexer tokens) error-handler)))
;;; --------------------------------------------------------------------
;;; No error, just grammar tests.
(check
(doit (make-lexical-token 'A #f 1)
(make-lexical-token 'B #f 2))
=> '(1 2))
(check
(doit (make-lexical-token 'C #f 3))
=> '3)
;;; --------------------------------------------------------------------
;;; Successful error recovery.
(check
;;Error, recovery, end-of-input.
(let ((r (doit (make-lexical-token 'A #f 1)
(make-lexical-token 'C #f 3))))
(cons r *error*))
=> '(error-form (error-handler "Syntax error: unexpected token : " . C)))
(check
;;Error, recovery, correct parse of "A B".
(let ((r (doit (make-lexical-token 'A #f 1)
(make-lexical-token 'C #f 3)
(make-lexical-token 'A #f 1)
(make-lexical-token 'B #f 2))))
(cons r *error*))
=> '((1 2)
(error-handler "Syntax error: unexpected token : " . C)))
;;; end of file
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