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;;; test-lr-associativity-01.scm --
;;
;;Show how to use left and right associativity. Notice that the
;;terminal M is declared as right associative; this influences the
;;binding of values to the $n symbols in the semantic clauses. The
;;semantic clause in the rule:
;;
;; (E M E M E) : (list $1 $2 (list $3 $4 $5))
;;
;;looks like it is right-associated, and it is because we have declared
;;M as "right:".
;;
(load "common-test.scm")
(define (doit . tokens)
(let ((parser (lalr-parser
(expect: 0)
(N (left: A)
(right: M)
(nonassoc: U))
(E (N) : $1
(E A E) : (list $1 $2 $3)
(E M E) : (list $1 $2 $3)
(E M E M E) : (list $1 $2 (list $3 $4 $5))
(A E (prec: U)) : (list '- $2)))))
(parser (make-lexer tokens) error-handler)))
;;; --------------------------------------------------------------------
;;; Single operator.
(check
(doit (make-lexical-token 'N #f 1))
=> 1)
(check
(doit (make-lexical-token 'N #f 1)
(make-lexical-token 'A #f '+)
(make-lexical-token 'N #f 2))
=> '(1 + 2))
(check
(doit (make-lexical-token 'N #f 1)
(make-lexical-token 'M #f '*)
(make-lexical-token 'N #f 2))
=> '(1 * 2))
(check
(doit (make-lexical-token 'A #f '-)
(make-lexical-token 'N #f 1))
=> '(- 1))
;;; --------------------------------------------------------------------
;;; Precedence.
(check
(doit (make-lexical-token 'N #f 1)
(make-lexical-token 'A #f '+)
(make-lexical-token 'N #f 2)
(make-lexical-token 'M #f '*)
(make-lexical-token 'N #f 3))
=> '(1 + (2 * 3)))
(check
(doit (make-lexical-token 'N #f 1)
(make-lexical-token 'M #f '*)
(make-lexical-token 'N #f 2)
(make-lexical-token 'A #f '+)
(make-lexical-token 'N #f 3))
=> '((1 * 2) + 3))
;;; --------------------------------------------------------------------
;;; Associativity.
(check
(doit (make-lexical-token 'N #f 1)
(make-lexical-token 'A #f '+)
(make-lexical-token 'N #f 2)
(make-lexical-token 'A #f '+)
(make-lexical-token 'N #f 3))
=> '((1 + 2) + 3))
(check
(doit (make-lexical-token 'N #f 1)
(make-lexical-token 'M #f '*)
(make-lexical-token 'N #f 2)
(make-lexical-token 'M #f '*)
(make-lexical-token 'N #f 3))
=> '(1 * (2 * 3)))
;;; end of file
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