test-suite/lalr/test-lr-associativity-01.scm

   1 ;;; test-lr-associativity-01.scm --
   2 ;;
   3 ;;Show  how  to use  left  and  right  associativity.  Notice  that  the
   4 ;;terminal  M is  declared  as right  associative;  this influences  the
   5 ;;binding  of values to  the $n  symbols in  the semantic  clauses.  The
   6 ;;semantic clause in the rule:
   7 ;;
   8 ;;  (E M E M E)     : (list $1 $2 (list $3 $4 $5))
   9 ;;
  10 ;;looks like it is right-associated,  and it is because we have declared
  11 ;;M as "right:".
  12 ;;
  13
  14 (load "common-test.scm")
  15
  16 (define (doit . tokens)
  17   (let ((parser (lalr-parser
  18                  (expect: 0)
  19                  (N (left: A)
  20                     (right: M)
  21                     (nonassoc: U))
  22                  (E     (N)             : $1
  23                         (E A E)         : (list $1 $2 $3)
  24                         (E M E)         : (list $1 $2 $3)
  25                         (E M E M E)     : (list $1 $2 (list $3 $4 $5))
  26                         (A E (prec: U)) : (list '- $2)))))
  27     (parser (make-lexer tokens) error-handler)))
  28
  29 ;;; --------------------------------------------------------------------
  30 ;;; Single operator.
  31
  32 (check
  33     (doit (make-lexical-token 'N #f 1))
  34   => 1)
  35
  36 (check
  37     (doit (make-lexical-token 'N #f 1)
  38           (make-lexical-token 'A #f '+)
  39           (make-lexical-token 'N #f 2))
  40   => '(1 + 2))
  41
  42 (check
  43     (doit (make-lexical-token 'N #f 1)
  44           (make-lexical-token 'M #f '*)
  45           (make-lexical-token 'N #f 2))
  46   => '(1 * 2))
  47
  48 (check
  49     (doit (make-lexical-token 'A #f '-)
  50           (make-lexical-token 'N #f 1))
  51   => '(- 1))
  52
  53 ;;; --------------------------------------------------------------------
  54 ;;; Precedence.
  55
  56 (check
  57     (doit (make-lexical-token 'N #f 1)
  58           (make-lexical-token 'A #f '+)
  59           (make-lexical-token 'N #f 2)
  60           (make-lexical-token 'M #f '*)
  61           (make-lexical-token 'N #f 3))
  62   => '(1 + (2 * 3)))
  63
  64 (check
  65     (doit (make-lexical-token 'N #f 1)
  66           (make-lexical-token 'M #f '*)
  67           (make-lexical-token 'N #f 2)
  68           (make-lexical-token 'A #f '+)
  69           (make-lexical-token 'N #f 3))
  70   => '((1 * 2) + 3))
  71
  72 ;;; --------------------------------------------------------------------
  73 ;;; Associativity.
  74
  75 (check
  76     (doit (make-lexical-token 'N #f 1)
  77           (make-lexical-token 'A #f '+)
  78           (make-lexical-token 'N #f 2)
  79           (make-lexical-token 'A #f '+)
  80           (make-lexical-token 'N #f 3))
  81   => '((1 + 2) + 3))
  82
  83 (check
  84     (doit (make-lexical-token 'N #f 1)
  85           (make-lexical-token 'M #f '*)
  86           (make-lexical-token 'N #f 2)
  87           (make-lexical-token 'M #f '*)
  88           (make-lexical-token 'N #f 3))
  89   => '(1 * (2 * 3)))
  90
  91 ;;; end of file