*** empty log message ***
original commit: 250709526458a0af817fe09a7abc5d85b5639640tokens
Scott Owens
23 years ago
parent
442aca5621
commit
96200c5baf
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#cs
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(module grammar mzscheme
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;; Constructs to create and access grammars, the internal
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;; representation of the input to the parser generator.
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(require (lib "list.ss")
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"yacc-helper.ss")
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(provide
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(rename export-make-item make-item)
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make-term
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make-non-term
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make-prec
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make-prod
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(rename make-gram make-grammar)
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;; Things that work on items
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start-item? item-prod item-prod-index item->string
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sym-at-dot move-dot-right item<? nullable-after-dot?
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;; Things that operate on grammar symbols
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gram-sym-symbol gram-sym-index term-prec gram-sym->string
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non-term? term? nullable? non-term<? term<?
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;; Things that work on precs
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prec-num prec-assoc
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;;Things that work on grammars
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get-nt-prods get-init-prod
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(rename gram-non-terms grammar-non-terms)
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(rename gram-terms grammar-terms)
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(rename gram-num-prods grammar-num-prods)
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(rename gram-prods grammar-prods)
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;; Things that work on productions
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prod-index prod-prec prod-rhs prod-lhs)
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;;---------------------- LR items --------------------------
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;; LR-item = (make-item production nat (int | #f))
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;; The n field contains the least integer such the item is nullable
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;; after the dot if the dot is to the right of the nth position.
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(define-struct item (prod dot-pos n))
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(define (export-make-item a b)
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(make-item a b #f))
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(define (item-prod-index x)
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(prod-index (item-prod x)))
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;; item<?: LR-item * LR-item -> bool
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;; Lexicographic comparison on two items.
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(define (item<? i1 i2)
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(let ((p1 (prod-index (item-prod i1)))
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(p2 (prod-index (item-prod i2))))
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(or (< p1 p2)
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(and (= p1 p2)
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(let ((d1 (item-dot-pos i1))
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(d2 (item-dot-pos i2)))
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(< d1 d2))))))
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(define (start-item? i)
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(= 0 (non-term-index (prod-lhs (item-prod i)))))
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;; move-dot-right: LR-item -> LR-item | #f
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;; moves the dot to the right in the item, unless it is at its
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;; rightmost, then it returns false
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(define (move-dot-right i)
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(cond
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((= (item-dot-pos i) (vector-length (prod-rhs (item-prod i)))) #f)
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(else (make-item (item-prod i)
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(add1 (item-dot-pos i))
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(item-n i)))))
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;; sym-at-dot: LR-item -> gram-sym | #f
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;; returns the symbol after the dot in the item or #f if there is none
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(define (sym-at-dot i)
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(cond
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((= (item-dot-pos i) (vector-length (prod-rhs (item-prod i)))) #f)
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(else (vector-ref (prod-rhs (item-prod i)) (item-dot-pos i)))))
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;; nullable-after-dot?: LR1-iten * grammar -> bool
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;; determines if the string after the dot is nullable
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(define (nullable-after-dot? i g)
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(cond
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((item-n i) => (lambda (x) (>= (item-dot-pos i) x)))
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(else
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(let ((str (prod-rhs (item-prod i))))
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(let loop ((c (sub1 (vector-length str))))
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(cond
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((= c -1) (set-item-n! i 0))
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((term? (vector-ref str c)) (set-item-n! i (add1 c)))
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((nullable? g (vector-ref str c)) (loop (sub1 c)))
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(else (set-item-n! i (add1 c))))))
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(>= (item-dot-pos i) (item-n i)))))
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;; print-item: LR-item ->
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(define (item->string it)
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(let ((print-sym (lambda (i)
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(let ((gs (vector-ref (prod-rhs (item-prod it)) i)))
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(cond
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((term? gs) (format "~a " (term-sym gs)))
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(else (format "~a " (non-term-sym gs))))))))
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(string-append
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(format "~a -> " (non-term-sym (prod-lhs (item-prod it))))
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(let loop ((i 0))
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(cond
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((= i (vector-length (prod-rhs (item-prod it))))
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(if (= i (item-dot-pos it))
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". "
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""))
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((= i (item-dot-pos it))
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(string-append ". " (print-sym i) (loop (add1 i))))
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(else (string-append (print-sym i) (loop (add1 i)))))))))
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;; --------------------- Grammar Symbols --------------------------
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;; gram-sym = (make-term symbol int prec)
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;; | (make-non-term symbol int)
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(define-struct term (sym index prec))
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(define-struct non-term (sym index))
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(define (non-term<? nt1 nt2)
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(< (non-term-index nt1) (non-term-index nt2)))
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(define (term<? nt1 nt2)
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(< (term-index nt1) (term-index nt2)))
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(define (gram-sym-index gs)
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(cond
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((term? gs) (term-index gs))
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(else (non-term-index gs))))
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(define (gram-sym-symbol gs)
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(cond
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((term? gs) (term-sym gs))
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(else (non-term-sym gs))))
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(define (gram-sym->string gs)
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(symbol->string (gram-sym-symbol gs)))
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;; ------------------------- Precedences ---------------------------
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;; a precedence declaration. the sym should be 'left 'right or 'nonassoc
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;; prec = (make-prec int sym)
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;; | #f
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(define-struct prec (num assoc))
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;; ------------------------- Grammar ------------------------------
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;; grammar = (make-gram (production list vector)
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;; (production list)
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;; (bool vector)
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;; (non-term list)
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;; (term list)
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;; int)
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;;
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;; The nt-prods field is indexed by the number assigned to the non-term and
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;; contains the list of productions for that non-term
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;; The prods field contains a list of all productions
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;; The nulls field is indexed by the index for a non-term and is trus iff
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;; the non-term is nullable
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(define-struct gram
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(nt-prods prods nulls non-terms terms num-prods))
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;; get-nt-prods: grammar * non-term -> production list
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;; returns the productions for the given non-term
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(define (get-nt-prods g nt)
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(vector-ref (gram-nt-prods g) (non-term-index nt)))
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;; get-init-prod: grammar -> production
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;; gets the starting production
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(define (get-init-prod g)
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(car (vector-ref (gram-nt-prods g) 0)))
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(define (nullable? g nt)
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(vector-ref (gram-nulls g) (non-term-index nt)))
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;; ------------------------ Productions ---------------------------
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;; production = (make-prod non-term (gram-sym vector) int prec)
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(define-struct prod (lhs rhs index prec))
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)
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@ -0,0 +1,60 @@
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#cs
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(module graph mzscheme
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(provide digraph)
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;; digraph:
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;; ('a list) * ('a -> 'a list) * ('a -> 'b) * ('b * 'b -> 'b) * 'b
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;; -> ('a -> 'b)
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;; DeRemer and Pennello 1982
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;; Computes (f x) = (f- x) union Union{(f y) | y in (edges x)}
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;; We use a hash-table to represent the result function 'a -> 'b set, so
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;; the values of type 'a must be comparable with equal?.
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(define (digraph nodes edges f- union fail)
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(letrec (
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;; Will map elements of 'a to 'b sets
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(results (make-hash-table 'equal))
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(f (lambda (x) (hash-table-get results x (lambda () fail))))
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;; Maps elements of 'a to integers.
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(N (make-hash-table 'equal))
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(get-N (lambda (x) (hash-table-get N x (lambda () 0))))
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(set-N (lambda (x d) (hash-table-put! N x d)))
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(stack null)
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(push (lambda (x) (set! stack (cons x stack))))
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(pop (lambda () (begin0 (car stack) (set! stack (cdr stack)))))
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(depth (lambda () (length stack)))
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;; traverse: 'a ->
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(traverse
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(lambda (x)
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(push x)
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(let ((d (depth)))
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(set-N x d)
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(hash-table-put! results x (f- x))
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(for-each (lambda (y)
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(if (= 0 (get-N y))
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(traverse y))
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(hash-table-put! results
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x
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(union (f x) (f y)))
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(set-N x (min (get-N x) (get-N y))))
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(edges x))
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(if (= d (get-N x))
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(let loop ((p (pop)))
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(set-N p +inf.0)
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(hash-table-put! results p (f x))
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(if (not (equal? x p))
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(loop (pop)))))))))
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(for-each (lambda (x)
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(if (= 0 (get-N x))
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(traverse x)))
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nodes)
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f))
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)
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@ -0,0 +1,356 @@
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#cs
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(module input-file-parser mzscheme
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;; routines for parsing the input to the parser generator and producing a
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;; grammar (See grammar.ss)
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(require "yacc-helper.ss" "terminal-syntax.ss" "grammar.ss" (lib "list.ss"))
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(provide parse-input)
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;; nullable: production list * int -> non-term set
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;; determines which non-terminals can derive epsilon
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(define (nullable prods num-nts)
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(letrec ((nullable (make-vector num-nts #f))
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(added #f)
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;; possible-nullable: producion list -> production list
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;; Removes all productions that have a terminal
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(possible-nullable
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(lambda (prods)
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(filter (lambda (prod)
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(vector-andmap non-term? (prod-rhs prod)))
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prods)))
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;; set-nullables: production list -> production list
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;; makes one pass through the productions, adding the ones
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;; known to be nullable now to nullable and returning a list
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;; of productions that we don't know about yet.
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(set-nullables
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(lambda (prods)
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(cond
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((null? prods) null)
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((vector-ref nullable
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(gram-sym-index (prod-lhs (car prods))))
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(set-nullables (cdr prods)))
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((vector-andmap (lambda (nt)
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(vector-ref nullable (gram-sym-index nt)))
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(prod-rhs (car prods)))
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(vector-set! nullable
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(gram-sym-index (prod-lhs (car prods)))
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#t)
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(set! added #t)
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(set-nullables (cdr prods)))
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(else
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(cons (car prods)
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(set-nullables (cdr prods))))))))
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(let loop ((P (possible-nullable prods)))
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(cond
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((null? P) nullable)
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(else
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(set! added #f)
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(let ((new-P (set-nullables P)))
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(if added
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(loop new-P)
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nullable)))))))
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;; Given the list of terminal symbols and the precedence/associativity definitions,
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;; builds terminal structures (See grammar.ss)
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;; build-terms: symbol list * symbol list list -> term list
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(define (build-terms term-list precs)
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(let ((counter 0)
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;;(term-list (cons (gensym) term-list))
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;; Will map a terminal symbol to its precedence/associativity
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(prec-table (make-hash-table)))
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;; Fill the prec table
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(for-each
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(lambda (p-decl)
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(begin0
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(let ((assoc (car p-decl)))
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(for-each
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(lambda (term-sym)
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(hash-table-put! prec-table term-sym (make-prec counter assoc)))
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(cdr p-decl)))
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(set! counter (add1 counter))))
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precs)
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(set! counter 0)
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;; Build the terminal structures
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(map
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(lambda (term-sym)
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(begin0
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(make-term term-sym
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counter
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(hash-table-get prec-table term-sym (lambda () #f)))
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(set! counter (add1 counter))))
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term-list)))
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;; Retrieves the terminal symbols from a terminals-def (See terminal-syntax.xx)
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;; get-terms-from-def: syntax-object -> symbol list
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(define (get-terms-from-def term-syn)
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(let ((t (syntax-local-value term-syn (lambda () #f))))
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(cond
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((terminals-def? t) (terminals-def-t t))
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(else
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(raise-syntax-error
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'parser-tokens
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"undefined token group"
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term-syn)))))
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;; parse-input: syntax-object^4 * string -> grammar
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(define (parse-input start term-defs prec-decls prods)
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(let* ((counter 0)
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(start-sym (syntax-object->datum start))
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;; Get the list of terminals out of input-terms
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(list-of-terms
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(syntax-case term-defs ()
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((term-def ...)
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(andmap identifier? (syntax->list term-defs))
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(remove-duplicates
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(apply append
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(map get-terms-from-def
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(syntax->list term-defs)))))
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(_
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(raise-syntax-error
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'parser-tokens
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"Token list must be (symbol ...)"
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term-defs))))
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(list-of-non-terms
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(syntax-case prods ()
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(((non-term production ...) ...)
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(begin
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(for-each
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(lambda (nts)
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(if (memq (syntax-object->datum nts) list-of-terms)
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||||||
|
(raise-syntax-error
|
||||||
|
'parser-non-terminals
|
||||||
|
(format "~a used as both token and non-terminal"
|
||||||
|
(syntax-object->datum nts))
|
||||||
|
nts)))
|
||||||
|
(syntax->list (syntax (non-term ...))))
|
||||||
|
|
||||||
|
(if (not (memq start-sym
|
||||||
|
(syntax-object->datum (syntax (non-term ...)))))
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-start
|
||||||
|
(format "Start symbol ~a not defined as a non-terminal"
|
||||||
|
start-sym)
|
||||||
|
start))
|
||||||
|
|
||||||
|
(let ((dup (duplicate-list? (syntax-object->datum
|
||||||
|
(syntax (non-term ...))))))
|
||||||
|
(if dup
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-non-terminals
|
||||||
|
(format "non-terminal ~a defined multiple times"
|
||||||
|
dup)
|
||||||
|
prods)))
|
||||||
|
|
||||||
|
(syntax-object->datum (syntax (non-term ...)))))
|
||||||
|
(_
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-productions
|
||||||
|
"Productions must be of the form ((non-terminal productions ...) ...)"
|
||||||
|
prods))))
|
||||||
|
|
||||||
|
;; Check the precedence declarations for errors and turn them into data
|
||||||
|
(precs
|
||||||
|
(syntax-case prec-decls ()
|
||||||
|
(((type term ...) ...)
|
||||||
|
(let ((p-terms
|
||||||
|
(apply append (syntax-object->datum
|
||||||
|
(syntax ((term ...) ...))))))
|
||||||
|
(cond
|
||||||
|
((duplicate-list? p-terms) =>
|
||||||
|
(lambda (d)
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-precedences
|
||||||
|
(format "duplicate precedence declaration for token ~a"
|
||||||
|
d)
|
||||||
|
prec-decls)))
|
||||||
|
(else
|
||||||
|
(for-each
|
||||||
|
(lambda (a)
|
||||||
|
(for-each
|
||||||
|
(lambda (t)
|
||||||
|
(if (not (memq (syntax-object->datum t)
|
||||||
|
list-of-terms))
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-precedences
|
||||||
|
(format
|
||||||
|
"Precedence declared for non-token ~a"
|
||||||
|
(syntax-object->datum t))
|
||||||
|
t)))
|
||||||
|
(syntax->list a)))
|
||||||
|
(syntax->list (syntax ((term ...) ...))))
|
||||||
|
(for-each
|
||||||
|
(lambda (type)
|
||||||
|
(if (not (memq (syntax-object->datum type)
|
||||||
|
`(left right nonassoc)))
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-precedences
|
||||||
|
"Associativity must be left, right or nonassoc"
|
||||||
|
type)))
|
||||||
|
(syntax->list (syntax (type ...))))
|
||||||
|
(syntax-object->datum prec-decls)))))
|
||||||
|
(_
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-precedences
|
||||||
|
"Precedence declaration must be of the form ((assoc term ...) ...) where assoc is left, right or nonassoc"
|
||||||
|
prec-decls))))
|
||||||
|
|
||||||
|
(terms (build-terms list-of-terms precs))
|
||||||
|
|
||||||
|
(non-terms (begin
|
||||||
|
(set! counter 1)
|
||||||
|
(map (lambda (non-term)
|
||||||
|
(begin0
|
||||||
|
(make-non-term non-term counter)
|
||||||
|
(set! counter (add1 counter))))
|
||||||
|
list-of-non-terms)))
|
||||||
|
(term-table (make-hash-table))
|
||||||
|
(non-term-table (make-hash-table)))
|
||||||
|
|
||||||
|
(for-each (lambda (t)
|
||||||
|
(hash-table-put! term-table (gram-sym-symbol t) t))
|
||||||
|
terms)
|
||||||
|
|
||||||
|
(for-each (lambda (nt)
|
||||||
|
(hash-table-put! non-term-table (gram-sym-symbol nt) nt))
|
||||||
|
non-terms)
|
||||||
|
|
||||||
|
(set! counter 1)
|
||||||
|
|
||||||
|
(let* (
|
||||||
|
;; parse-prod: syntax-object -> gram-sym vector
|
||||||
|
(parse-prod
|
||||||
|
(lambda (prod-so)
|
||||||
|
(syntax-case prod-so ()
|
||||||
|
((prod-rhs-sym ...)
|
||||||
|
(andmap identifier? (syntax->list prod-so))
|
||||||
|
(list->vector
|
||||||
|
(map (lambda (s)
|
||||||
|
(hash-table-get
|
||||||
|
term-table
|
||||||
|
(syntax-object->datum s)
|
||||||
|
(lambda ()
|
||||||
|
(hash-table-get
|
||||||
|
non-term-table
|
||||||
|
(syntax-object->datum s)
|
||||||
|
(lambda ()
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-production-rhs
|
||||||
|
(format
|
||||||
|
"~a is not declared as a terminal or non-terminal"
|
||||||
|
(syntax-object->datum s))
|
||||||
|
s))))))
|
||||||
|
(syntax->list prod-so))))
|
||||||
|
(_
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-production-rhs
|
||||||
|
"production right-hand-side must have form (symbol ...)"
|
||||||
|
prod-so)))))
|
||||||
|
|
||||||
|
;; parse-prod+action: non-term * syntax-object -> production
|
||||||
|
(parse-prod+action
|
||||||
|
(lambda (nt prod-so)
|
||||||
|
(syntax-case prod-so (prec)
|
||||||
|
((prod-rhs action)
|
||||||
|
(let ((p (parse-prod (syntax prod-rhs))))
|
||||||
|
(begin0
|
||||||
|
(make-prod
|
||||||
|
nt
|
||||||
|
p
|
||||||
|
counter
|
||||||
|
(let loop ((i (sub1 (vector-length p))))
|
||||||
|
(if (>= i 0)
|
||||||
|
(let ((gs (vector-ref p i)))
|
||||||
|
(if (term? gs)
|
||||||
|
(term-prec gs)
|
||||||
|
(loop (sub1 i))))
|
||||||
|
#f)))
|
||||||
|
(set! counter (add1 counter)))))
|
||||||
|
((prod-rhs (prec term) action)
|
||||||
|
(identifier? (syntax term))
|
||||||
|
(begin0
|
||||||
|
(make-prod
|
||||||
|
nt
|
||||||
|
(parse-prod (syntax prod-rhs))
|
||||||
|
counter
|
||||||
|
(term-prec
|
||||||
|
(hash-table-get
|
||||||
|
term-table
|
||||||
|
(syntax-object->datum (syntax term))
|
||||||
|
(lambda ()
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-production-rhs
|
||||||
|
(format
|
||||||
|
"unrecognized terminal ~a in precedence declaration"
|
||||||
|
(syntax-object->datum (syntax term)))
|
||||||
|
(syntax term)))))
|
||||||
|
(set! counter (add1 counter)))))
|
||||||
|
(_
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-production-rhs
|
||||||
|
"production must have form [(symbol ...) expression] or [(symbol ...) (prec symbol) expression]"
|
||||||
|
prod-so)))))
|
||||||
|
|
||||||
|
;; parse-prod-for-nt: syntax-object -> production list
|
||||||
|
(parse-prods-for-nt
|
||||||
|
(lambda (prods-so)
|
||||||
|
(syntax-case prods-so ()
|
||||||
|
((nt productions ...)
|
||||||
|
(> (length (syntax->list (syntax (productions ...)))) 0)
|
||||||
|
(let* ((prods (syntax-e prods-so))
|
||||||
|
(nt (hash-table-get non-term-table
|
||||||
|
(syntax-e (car prods)))))
|
||||||
|
(map (lambda (p) (parse-prod+action nt p))
|
||||||
|
(cdr prods))))
|
||||||
|
(_
|
||||||
|
(raise-syntax-error
|
||||||
|
'parser-productions
|
||||||
|
"A production for a non-terminal must be (non-term right-hand-side ...) with at least 1 right hand side"
|
||||||
|
prods-so))))))
|
||||||
|
|
||||||
|
(let* ((start (make-non-term 'Start 0))
|
||||||
|
(prods
|
||||||
|
(cons
|
||||||
|
(list (make-prod start
|
||||||
|
(vector (hash-table-get non-term-table
|
||||||
|
start-sym))
|
||||||
|
0
|
||||||
|
#f))
|
||||||
|
(map parse-prods-for-nt (syntax->list prods))))
|
||||||
|
(nulls (nullable (apply append prods)
|
||||||
|
(add1 (length non-terms)))))
|
||||||
|
|
||||||
|
|
||||||
|
(printf "nullable: {~a}~n~n"
|
||||||
|
(apply string-append
|
||||||
|
(let loop ((i 0))
|
||||||
|
(cond
|
||||||
|
((>= i (vector-length nulls)) null)
|
||||||
|
((vector-ref nulls i)
|
||||||
|
(cons
|
||||||
|
(format "~a"
|
||||||
|
(gram-sym-symbol
|
||||||
|
(list-ref (cons start non-terms) i)))
|
||||||
|
(loop (add1 i))))
|
||||||
|
(else (loop (add1 i)))))))
|
||||||
|
(make-grammar
|
||||||
|
(list->vector prods)
|
||||||
|
(apply append prods)
|
||||||
|
nulls
|
||||||
|
(cons start non-terms)
|
||||||
|
terms
|
||||||
|
counter))))))
|
||||||
@ -0,0 +1,126 @@
|
|||||||
|
#cs
|
||||||
|
(module lalr mzscheme
|
||||||
|
|
||||||
|
;; Compute LALR lookaheads from DeRemer and Pennello 1982
|
||||||
|
|
||||||
|
(require "lr0.ss"
|
||||||
|
"grammar.ss"
|
||||||
|
"graph.ss"
|
||||||
|
"array2d.ss"
|
||||||
|
(lib "list.ss"))
|
||||||
|
|
||||||
|
(provide compute-LA)
|
||||||
|
|
||||||
|
(define (array2d-add! a i1 i2 v)
|
||||||
|
(let ((old (array2d-ref a i1 i2)))
|
||||||
|
(array2d-set! a i1 i2 (cons v old))))
|
||||||
|
|
||||||
|
;; compute-DR: LR0-automaton * grammar -> (trans-key -> term list)
|
||||||
|
;; computes for each state, non-term transition pair, the terminals
|
||||||
|
;; which can transition out of the resulting state
|
||||||
|
(define (compute-DR a g)
|
||||||
|
(lambda (tk)
|
||||||
|
(let ((r (run-automaton (trans-key-st tk) (trans-key-gs tk) a)))
|
||||||
|
(filter
|
||||||
|
(lambda (term)
|
||||||
|
(run-automaton r term a))
|
||||||
|
(grammar-terms g)))))
|
||||||
|
|
||||||
|
;; compute-reads:
|
||||||
|
;; LR0-automaton * grammar -> (trans-key -> trans-key list)
|
||||||
|
(define (compute-reads a g)
|
||||||
|
(lambda (tk)
|
||||||
|
(let ((r (run-automaton (trans-key-st tk) (trans-key-gs tk) a)))
|
||||||
|
(map (lambda (x) (make-trans-key r x))
|
||||||
|
(filter (lambda (non-term)
|
||||||
|
(and (nullable? g non-term)
|
||||||
|
(run-automaton r non-term a)))
|
||||||
|
(grammar-non-terms g))))))
|
||||||
|
|
||||||
|
;; compute-read: LR0-automaton * grammar -> (trans-key -> term list)
|
||||||
|
(define (compute-read a g)
|
||||||
|
(let* ((dr (compute-DR a g))
|
||||||
|
(reads (compute-reads a g)))
|
||||||
|
(digraph (filter (lambda (x) (non-term? (trans-key-gs x)))
|
||||||
|
(hash-table-map (lr0-transitions a) (lambda (k v) k)))
|
||||||
|
reads
|
||||||
|
dr
|
||||||
|
(union term<?)
|
||||||
|
null)))
|
||||||
|
|
||||||
|
|
||||||
|
;; comput-includes-and-lookback:
|
||||||
|
;; lr0-automaton * grammar -> (value (trans-key -> trans-key list)
|
||||||
|
;; (kernel * prod -> trans-key list))
|
||||||
|
(define (compute-includes-and-lookback a g)
|
||||||
|
(let* ((states (lr0-states a))
|
||||||
|
(non-terms (grammar-non-terms g))
|
||||||
|
(num-states (vector-length states))
|
||||||
|
(num-non-terms (length non-terms))
|
||||||
|
(includes (make-array2d num-states num-non-terms null))
|
||||||
|
(lookback (make-array2d num-states
|
||||||
|
(grammar-num-prods g)
|
||||||
|
null)))
|
||||||
|
(let loop ((state 0))
|
||||||
|
(if (< state num-states)
|
||||||
|
(begin
|
||||||
|
(for-each
|
||||||
|
(lambda (non-term)
|
||||||
|
(for-each
|
||||||
|
(lambda (prod)
|
||||||
|
(let loop ((i (make-item prod 0))
|
||||||
|
(p (vector-ref states state)))
|
||||||
|
(if (and p i)
|
||||||
|
(begin
|
||||||
|
(if (and (non-term? (sym-at-dot i))
|
||||||
|
(nullable-after-dot? (move-dot-right i)
|
||||||
|
g))
|
||||||
|
(array2d-add! includes
|
||||||
|
(kernel-index p)
|
||||||
|
(gram-sym-index
|
||||||
|
(sym-at-dot i))
|
||||||
|
(make-trans-key
|
||||||
|
(vector-ref states state)
|
||||||
|
non-term)))
|
||||||
|
(if (not (move-dot-right i))
|
||||||
|
(array2d-add! lookback
|
||||||
|
(kernel-index p)
|
||||||
|
(prod-index prod)
|
||||||
|
(make-trans-key
|
||||||
|
(vector-ref states state)
|
||||||
|
non-term)))
|
||||||
|
(loop (move-dot-right i)
|
||||||
|
(run-automaton p (sym-at-dot i) a))))))
|
||||||
|
(get-nt-prods g non-term)))
|
||||||
|
non-terms)
|
||||||
|
(loop (add1 state)))))
|
||||||
|
(values (lambda (tk)
|
||||||
|
(array2d-ref includes
|
||||||
|
(kernel-index (trans-key-st tk))
|
||||||
|
(gram-sym-index (trans-key-gs tk))))
|
||||||
|
(lambda (state prod)
|
||||||
|
(array2d-ref lookback
|
||||||
|
(kernel-index state)
|
||||||
|
(prod-index prod))))))
|
||||||
|
|
||||||
|
|
||||||
|
;; compute-follow: LR0-automaton * grammar -> (trans-key -> term list)
|
||||||
|
(define (compute-follow a g includes)
|
||||||
|
(let ((read (compute-read a g)))
|
||||||
|
(digraph (filter (lambda (x) (non-term? (trans-key-gs x)))
|
||||||
|
(hash-table-map (lr0-transitions a) (lambda (k v) k)))
|
||||||
|
includes
|
||||||
|
read
|
||||||
|
(union term<?)
|
||||||
|
null)))
|
||||||
|
|
||||||
|
;; compute-LA: LR0-automaton * grammar -> (kernel * prod -> term list)
|
||||||
|
(define (compute-LA a g)
|
||||||
|
(let-values (((includes lookback) (compute-includes-and-lookback a g)))
|
||||||
|
(let ((follow (compute-follow a g includes)))
|
||||||
|
(lambda (k p)
|
||||||
|
(let* ((l (lookback k p))
|
||||||
|
(f (map follow l)))
|
||||||
|
(apply append f))))))
|
||||||
|
|
||||||
|
)
|
||||||
@ -0,0 +1,247 @@
|
|||||||
|
#cs
|
||||||
|
(module lr0 mzscheme
|
||||||
|
|
||||||
|
;; Handle the LR0 automaton
|
||||||
|
|
||||||
|
(require "grammar.ss"
|
||||||
|
"graph.ss"
|
||||||
|
(lib "list.ss"))
|
||||||
|
|
||||||
|
(provide union build-lr0-automaton run-automaton (struct trans-key (st gs))
|
||||||
|
lr0-transitions lr0-states kernel-items kernel-index)
|
||||||
|
|
||||||
|
(define (union comp<?)
|
||||||
|
(letrec ((union
|
||||||
|
(lambda (l1 l2)
|
||||||
|
(cond
|
||||||
|
((null? l1) l2)
|
||||||
|
((null? l2) l1)
|
||||||
|
(else (let ((c1 (car l1))
|
||||||
|
(c2 (car l2)))
|
||||||
|
(cond
|
||||||
|
((comp<? c1 c2)
|
||||||
|
(cons c1 (union (cdr l1) l2)))
|
||||||
|
((comp<? c2 c1)
|
||||||
|
(cons c2 (union l1 (cdr l2))))
|
||||||
|
(else (union (cdr l1) l2)))))))))
|
||||||
|
union))
|
||||||
|
|
||||||
|
;; kernel = (make-kernel (LR1-item list) index)
|
||||||
|
;; the list must be kept sorted according to item<? so that equal? can
|
||||||
|
;; be used to compare kernels
|
||||||
|
;; LR0-automaton = (make-lr0 (trans-key kernel hash-table) (kernel vector))
|
||||||
|
;; trans-key = (make-trans-key kernel gram-sym)
|
||||||
|
(define-struct kernel (items index))
|
||||||
|
(define-struct trans-key (st gs))
|
||||||
|
(define-struct lr0 (transitions states))
|
||||||
|
|
||||||
|
;; The kernels in the automaton are represented cannonically.
|
||||||
|
;; That is (equal? a b) <=> (eq? a b)
|
||||||
|
(define (kernel->string k)
|
||||||
|
(apply string-append
|
||||||
|
`("{" ,@(map (lambda (i) (string-append (item->string i) ", "))
|
||||||
|
(kernel-items k))
|
||||||
|
"}")))
|
||||||
|
|
||||||
|
;; run-automaton: kernel * gram-sym * LR0-automaton -> kernel | #f
|
||||||
|
;; returns the state that the transition trans-key provides or #f
|
||||||
|
;; if there is no such state
|
||||||
|
(define (run-automaton k s a)
|
||||||
|
(hash-table-get (lr0-transitions a) (make-trans-key k s) (lambda () #f)))
|
||||||
|
|
||||||
|
|
||||||
|
;; build-LR0-automaton: grammar -> LR0-automaton
|
||||||
|
;; Constructs the kernels of the sets of LR(0) items of g
|
||||||
|
(define (build-lr0-automaton grammar)
|
||||||
|
; (printf "LR(0) automaton:~n")
|
||||||
|
(letrec (
|
||||||
|
(terms (list->vector (grammar-terms grammar)))
|
||||||
|
(non-terms (list->vector (grammar-non-terms grammar)))
|
||||||
|
(num-non-terms (vector-length non-terms))
|
||||||
|
(num-gram-syms (+ num-non-terms (vector-length terms)))
|
||||||
|
|
||||||
|
|
||||||
|
;; first-non-term: non-term -> non-term list
|
||||||
|
;; given a non-terminal symbol C, return those non-terminal
|
||||||
|
;; symbols A s.t. C -> An for some string of terminals and
|
||||||
|
;; non-terminals n where -> means a rightmost derivation in many
|
||||||
|
;; steps. Assumes that each non-term can be reduces to a string
|
||||||
|
;; of terms.
|
||||||
|
(first-non-term
|
||||||
|
(digraph (grammar-non-terms grammar)
|
||||||
|
(lambda (nt)
|
||||||
|
(filter non-term?
|
||||||
|
(map (lambda (prod)
|
||||||
|
(sym-at-dot (make-item prod 0)))
|
||||||
|
(get-nt-prods grammar nt))))
|
||||||
|
(lambda (nt) (list nt))
|
||||||
|
(union non-term<?)
|
||||||
|
null))
|
||||||
|
|
||||||
|
;; closure: LR1-item list -> LR1-item list
|
||||||
|
;; Creates a set of items containing i s.t. if A -> n.Xm is in it,
|
||||||
|
;; X -> .o is in it too.
|
||||||
|
(LR0-closure
|
||||||
|
(lambda (i)
|
||||||
|
(cond
|
||||||
|
((null? i) null)
|
||||||
|
(else
|
||||||
|
(let ((next-gsym (sym-at-dot (car i))))
|
||||||
|
(cond
|
||||||
|
((non-term? next-gsym)
|
||||||
|
(cons (car i)
|
||||||
|
(append
|
||||||
|
(apply append
|
||||||
|
(map (lambda (non-term)
|
||||||
|
(map (lambda (x)
|
||||||
|
(make-item x 0))
|
||||||
|
(get-nt-prods grammar
|
||||||
|
non-term)))
|
||||||
|
(first-non-term next-gsym)))
|
||||||
|
(LR0-closure (cdr i)))))
|
||||||
|
(else
|
||||||
|
(cons (car i) (LR0-closure (cdr i))))))))))
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
;; maps trans-keys to kernels
|
||||||
|
(automaton (make-hash-table 'equal))
|
||||||
|
|
||||||
|
;; keeps the kernels we have seen, so we can have a unique
|
||||||
|
;; list for each kernel
|
||||||
|
(kernels (make-hash-table 'equal))
|
||||||
|
|
||||||
|
(counter 1)
|
||||||
|
|
||||||
|
;; goto: LR1-item list -> LR1-item list list
|
||||||
|
;; creates new kernels by moving the dot in each item in the
|
||||||
|
;; LR0-closure of kernel to the right, and grouping them by
|
||||||
|
;; the term/non-term moved over. Returns the kernels not
|
||||||
|
;; yet seen, and places the trans-keys into automaton
|
||||||
|
(goto
|
||||||
|
(lambda (kernel)
|
||||||
|
(let (
|
||||||
|
;; maps each gram-syms to a list of items
|
||||||
|
|
||||||
|
(table (make-vector num-gram-syms null))
|
||||||
|
|
||||||
|
;; add-item!:
|
||||||
|
;; (item list) vector * item ->
|
||||||
|
;; adds i into the table grouped with the grammar
|
||||||
|
;; symbol following its dot
|
||||||
|
(add-item!
|
||||||
|
(lambda (table i)
|
||||||
|
(let ((gs (sym-at-dot i)))
|
||||||
|
(if gs
|
||||||
|
(let* ((add (if (term? gs)
|
||||||
|
num-non-terms
|
||||||
|
0))
|
||||||
|
(already
|
||||||
|
(vector-ref table
|
||||||
|
(+ add
|
||||||
|
(gram-sym-index gs)))))
|
||||||
|
(if (not (member i already))
|
||||||
|
(vector-set! table
|
||||||
|
(+ add (gram-sym-index gs))
|
||||||
|
(cons i already)))))))))
|
||||||
|
|
||||||
|
;; Group the items of the LR0 closure of the kernel
|
||||||
|
;; by the character after the dot
|
||||||
|
(for-each (lambda (item)
|
||||||
|
(add-item! table item))
|
||||||
|
(LR0-closure (kernel-items kernel)))
|
||||||
|
|
||||||
|
|
||||||
|
;; each group is a new kernel, with the dot advanced.
|
||||||
|
;; sorts the items in a kernel so kernels can be compared
|
||||||
|
;; with equal? for using the table kernels to make sure
|
||||||
|
;; only one representitive of each kernel is created
|
||||||
|
(filter
|
||||||
|
(lambda (x) x)
|
||||||
|
(map
|
||||||
|
(lambda (i)
|
||||||
|
(let* ((gs (car i))
|
||||||
|
(items (cadr i))
|
||||||
|
(new #f)
|
||||||
|
(new-kernel (quicksort
|
||||||
|
(filter (lambda (x) x)
|
||||||
|
(map move-dot-right items))
|
||||||
|
item<?))
|
||||||
|
(unique-kernel (hash-table-get
|
||||||
|
kernels
|
||||||
|
new-kernel
|
||||||
|
(lambda ()
|
||||||
|
(let ((k (make-kernel
|
||||||
|
new-kernel
|
||||||
|
counter)))
|
||||||
|
(set! new #t)
|
||||||
|
(set! counter (add1 counter))
|
||||||
|
(hash-table-put! kernels
|
||||||
|
new-kernel
|
||||||
|
k)
|
||||||
|
k)))))
|
||||||
|
(hash-table-put! automaton
|
||||||
|
(make-trans-key kernel gs)
|
||||||
|
unique-kernel)
|
||||||
|
; (printf "~a -> ~a on ~a~n"
|
||||||
|
; (kernel->string kernel)
|
||||||
|
; (kernel->string unique-kernel)
|
||||||
|
; (gram-sym-symbol gs))
|
||||||
|
(if new
|
||||||
|
unique-kernel
|
||||||
|
#f)))
|
||||||
|
(let loop ((i 0))
|
||||||
|
(cond
|
||||||
|
((< i num-non-terms)
|
||||||
|
(let ((items (vector-ref table i)))
|
||||||
|
(cond
|
||||||
|
((null? items) (loop (add1 i)))
|
||||||
|
(else
|
||||||
|
(cons (list (vector-ref non-terms i) items)
|
||||||
|
(loop (add1 i)))))))
|
||||||
|
((< i num-gram-syms)
|
||||||
|
(let ((items (vector-ref table i)))
|
||||||
|
(cond
|
||||||
|
((null? items) (loop (add1 i)))
|
||||||
|
(else
|
||||||
|
(cons (list (vector-ref terms (- i num-non-terms))
|
||||||
|
items)
|
||||||
|
(loop (add1 i)))))))
|
||||||
|
(else null))))))))
|
||||||
|
|
||||||
|
|
||||||
|
(start (list (make-item (get-init-prod grammar) 0)))
|
||||||
|
(startk (make-kernel start 0))
|
||||||
|
(new-kernels (make-queue)))
|
||||||
|
|
||||||
|
(hash-table-put! kernels start startk)
|
||||||
|
(let loop ((old-kernels (list startk))
|
||||||
|
(seen-kernels null))
|
||||||
|
(cond
|
||||||
|
((and (empty-queue? new-kernels) (null? old-kernels))
|
||||||
|
(make-lr0 automaton (list->vector (reverse! seen-kernels))))
|
||||||
|
((null? old-kernels)
|
||||||
|
(loop (deq! new-kernels) seen-kernels))
|
||||||
|
(else
|
||||||
|
(enq! new-kernels (goto (car old-kernels)))
|
||||||
|
(loop (cdr old-kernels) (cons (car old-kernels) seen-kernels)))))))
|
||||||
|
|
||||||
|
(define-struct q (f l))
|
||||||
|
(define (empty-queue? q)
|
||||||
|
(null? (q-f q)))
|
||||||
|
(define (make-queue)
|
||||||
|
(make-q null null))
|
||||||
|
(define (enq! q i)
|
||||||
|
(if (empty-queue? q)
|
||||||
|
(let ((i (list i)))
|
||||||
|
(set-q-l! q i)
|
||||||
|
(set-q-f! q i))
|
||||||
|
(begin
|
||||||
|
(set-cdr! (q-l q) (list i))
|
||||||
|
(set-q-l! q (cdr (q-l q))))))
|
||||||
|
(define (deq! q)
|
||||||
|
(begin0
|
||||||
|
(car (q-f q))
|
||||||
|
(set-q-f! q (cdr (q-f q)))))
|
||||||
|
|
||||||
|
)
|
||||||
@ -0,0 +1,19 @@
|
|||||||
|
#cs
|
||||||
|
(module parser-actions mzscheme
|
||||||
|
|
||||||
|
;; The entries into the action table
|
||||||
|
|
||||||
|
(provide shift? reduce? accept?
|
||||||
|
shift-state reduce-prod-num reduce-lhs-num reduce-rhs-length
|
||||||
|
make-shift make-reduce)
|
||||||
|
|
||||||
|
;; action = (shift int)
|
||||||
|
;; | (reduce int int int)
|
||||||
|
;; | (accept)
|
||||||
|
;; | int
|
||||||
|
;; | #f
|
||||||
|
|
||||||
|
(define-struct shift (state))
|
||||||
|
(define-struct reduce (prod-num lhs-num rhs-length))
|
||||||
|
(define-struct accept ())
|
||||||
|
)
|
||||||
@ -0,0 +1,77 @@
|
|||||||
|
#cs
|
||||||
|
(module parser-builder mzscheme
|
||||||
|
|
||||||
|
(require "input-file-parser.ss"
|
||||||
|
"table.ss"
|
||||||
|
"parser-actions.ss"
|
||||||
|
"grammar.ss"
|
||||||
|
(lib "pretty.ss"))
|
||||||
|
|
||||||
|
(provide build-parser)
|
||||||
|
|
||||||
|
(define (build-parser start input-terms assocs prods filename runtime src)
|
||||||
|
(let* ((grammar (parse-input start input-terms assocs prods))
|
||||||
|
(table (build-table grammar ""))
|
||||||
|
(table-code
|
||||||
|
(cons 'vector
|
||||||
|
(map (lambda (action)
|
||||||
|
(cond
|
||||||
|
((shift? action)
|
||||||
|
`(make-shift ,(shift-state action)))
|
||||||
|
((reduce? action)
|
||||||
|
`(make-reduce ,(reduce-prod-num action)
|
||||||
|
,(reduce-lhs-num action)
|
||||||
|
,(reduce-rhs-length action)))
|
||||||
|
((accept? action)
|
||||||
|
`(make-accept))
|
||||||
|
(else action)))
|
||||||
|
(vector->list table))))
|
||||||
|
|
||||||
|
(num-non-terms (length (grammar-non-terms grammar)))
|
||||||
|
|
||||||
|
(token-code
|
||||||
|
`(let ((ht (make-hash-table)))
|
||||||
|
(begin
|
||||||
|
,@(map (lambda (term)
|
||||||
|
`(hash-table-put! ht
|
||||||
|
',(gram-sym-symbol term)
|
||||||
|
,(+ num-non-terms (gram-sym-index term))))
|
||||||
|
(grammar-terms grammar))
|
||||||
|
ht)))
|
||||||
|
|
||||||
|
(parser-code
|
||||||
|
`(letrec ((term-sym->index ,token-code)
|
||||||
|
(table ,table-code)
|
||||||
|
(pop-2x
|
||||||
|
(lambda (s n)
|
||||||
|
(if (> n 0)
|
||||||
|
(pop-2x (cdr (cdr s)) (sub1 n))
|
||||||
|
s))))
|
||||||
|
(lambda (get-token)
|
||||||
|
(let loop ((stack (list 0)))
|
||||||
|
(let* ((next (get-token))
|
||||||
|
(s (car stack))
|
||||||
|
(a (hash-table-get term-sym->index
|
||||||
|
(if (token? next)
|
||||||
|
(token-name next)
|
||||||
|
next)))
|
||||||
|
(action (array2d-ref table s a)))
|
||||||
|
(cond
|
||||||
|
((shift? action)
|
||||||
|
(loop (cons (shift-state action) (cons a stack))))
|
||||||
|
((reduce? action)
|
||||||
|
(display (reduce-prod-num action))
|
||||||
|
(newline)
|
||||||
|
(let* ((A (reduce-lhs-num action))
|
||||||
|
(new-stack (pop-2x stack (reduce-rhs-length action)))
|
||||||
|
(goto (array2d-ref table (car new-stack) A)))
|
||||||
|
(loop (cons goto (cons A new-stack)))))
|
||||||
|
((accept? action)
|
||||||
|
(printf "accept~n")))))))))
|
||||||
|
(pretty-print parser-code)
|
||||||
|
(newline)
|
||||||
|
(datum->syntax-object
|
||||||
|
runtime
|
||||||
|
parser-code
|
||||||
|
src))))
|
||||||
|
|
||||||
@ -0,0 +1,286 @@
|
|||||||
|
#cs
|
||||||
|
(module table mzscheme
|
||||||
|
|
||||||
|
;; Routine to build the LALR table
|
||||||
|
|
||||||
|
(require "grammar.ss"
|
||||||
|
"lr0.ss"
|
||||||
|
"array2d.ss"
|
||||||
|
"lalr.ss"
|
||||||
|
"parser-actions.ss"
|
||||||
|
(lib "list.ss"))
|
||||||
|
|
||||||
|
(provide build-table)
|
||||||
|
|
||||||
|
;; print-entry: symbol * action * output-port ->
|
||||||
|
;; prints the action a for lookahead sym to port
|
||||||
|
(define (print-entry sym a port)
|
||||||
|
(let ((s "\t~a\t\t\t\t\t~a\t~a\n"))
|
||||||
|
(cond
|
||||||
|
((shift? a)
|
||||||
|
(fprintf port s sym "shift" (shift-state a)))
|
||||||
|
((reduce? a)
|
||||||
|
(fprintf port s sym "reduce" (reduce-prod-num a)))
|
||||||
|
((accept? a)
|
||||||
|
(fprintf port s sym "accept" ""))
|
||||||
|
(a
|
||||||
|
(fprintf port s sym "goto" a)))))
|
||||||
|
|
||||||
|
|
||||||
|
;; count: ('a -> bool) * 'a list -> num
|
||||||
|
;; counts the number of elements in list that satisfy pred
|
||||||
|
(define (count pred list)
|
||||||
|
(cond
|
||||||
|
((null? list) 0)
|
||||||
|
((pred (car list)) (+ 1 (count pred (cdr list))))
|
||||||
|
(else (count pred (cdr list)))))
|
||||||
|
|
||||||
|
|
||||||
|
;; display-parser:
|
||||||
|
;; action array2d * term vector * non-term vector * kernel vector *
|
||||||
|
;; output-port ->
|
||||||
|
;; Prints out the parser given by table.
|
||||||
|
(define (display-parser table terms non-terms states port)
|
||||||
|
(let* ((num-terms (vector-length terms))
|
||||||
|
(num-non-terms (vector-length non-terms))
|
||||||
|
(num-gram-syms (+ num-terms num-non-terms))
|
||||||
|
(num-states (vector-length states))
|
||||||
|
(SR-conflicts 0)
|
||||||
|
(RR-conflicts 0))
|
||||||
|
(let loop ((i 0))
|
||||||
|
(if (< i num-states)
|
||||||
|
(begin
|
||||||
|
(fprintf port "State ~a~n" i)
|
||||||
|
(for-each (lambda (item)
|
||||||
|
(fprintf port "\t~a~n" (item->string item)))
|
||||||
|
(kernel-items (vector-ref states i)))
|
||||||
|
(newline port)
|
||||||
|
(let loop ((j 0))
|
||||||
|
(if (< j num-terms)
|
||||||
|
(begin
|
||||||
|
(let ((act (array2d-ref
|
||||||
|
table
|
||||||
|
i
|
||||||
|
(+ j num-non-terms))))
|
||||||
|
(cond
|
||||||
|
((list? act)
|
||||||
|
(fprintf port "begin conflict:~n")
|
||||||
|
(if (> (count reduce? act) 1)
|
||||||
|
(set! RR-conflicts (add1 RR-conflicts)))
|
||||||
|
(if (> (count shift? act) 0)
|
||||||
|
(set! SR-conflicts (add1 SR-conflicts)))
|
||||||
|
(map (lambda (x)
|
||||||
|
(print-entry
|
||||||
|
(gram-sym-symbol (vector-ref terms j))
|
||||||
|
x
|
||||||
|
port))
|
||||||
|
act)
|
||||||
|
(fprintf port "end conflict~n"))
|
||||||
|
(act (print-entry
|
||||||
|
(gram-sym-symbol (vector-ref terms j))
|
||||||
|
act
|
||||||
|
port))))
|
||||||
|
(loop (add1 j)))))
|
||||||
|
|
||||||
|
(newline port)
|
||||||
|
|
||||||
|
(let loop ((j 0))
|
||||||
|
(if (< j num-non-terms)
|
||||||
|
(begin
|
||||||
|
(let ((s (array2d-ref table i j)))
|
||||||
|
(if s
|
||||||
|
(print-entry
|
||||||
|
(gram-sym-symbol (vector-ref non-terms j))
|
||||||
|
s
|
||||||
|
port)))
|
||||||
|
(loop (add1 j)))))
|
||||||
|
|
||||||
|
(newline port)
|
||||||
|
(loop (add1 i)))))
|
||||||
|
(if (> SR-conflicts 0)
|
||||||
|
(fprintf port "~a shift/reduce conflicts~n" SR-conflicts))
|
||||||
|
(if (> RR-conflicts 0)
|
||||||
|
(fprintf port "~a reduce/reduce conflicts~n" RR-conflicts))))
|
||||||
|
|
||||||
|
(define (resolve-conflicts table num-states num-terms num-non-terms)
|
||||||
|
(letrec ((SR-conflicts 0)
|
||||||
|
(RR-conflicts 0)
|
||||||
|
(get-action
|
||||||
|
(lambda (entry)
|
||||||
|
(cond
|
||||||
|
((list? entry)
|
||||||
|
(if (> (count shift? entry) 0)
|
||||||
|
(set! SR-conflicts (add1 SR-conflicts)))
|
||||||
|
(if (> (count reduce? entry) 1)
|
||||||
|
(set! RR-conflicts (add1 RR-conflicts)))
|
||||||
|
(let loop ((current-guess (make-reduce +inf.0 -1 -1))
|
||||||
|
(rest entry))
|
||||||
|
(cond
|
||||||
|
((null? rest) current-guess)
|
||||||
|
((shift? (car rest)) (car rest))
|
||||||
|
((< (reduce-prod-num (car rest))
|
||||||
|
(reduce-prod-num current-guess))
|
||||||
|
(loop (car rest) (cdr rest)))
|
||||||
|
(else (loop current-guess (cdr rest))))))
|
||||||
|
(else entry)))))
|
||||||
|
(let loop ((state 0))
|
||||||
|
(if (< state num-states)
|
||||||
|
(begin
|
||||||
|
(let loop ((term 0))
|
||||||
|
(if (< term num-terms)
|
||||||
|
(begin
|
||||||
|
(array2d-set! table state (+ num-non-terms term)
|
||||||
|
(get-action
|
||||||
|
(array2d-ref table
|
||||||
|
state
|
||||||
|
(+ num-non-terms term))))
|
||||||
|
(loop (add1 term)))))
|
||||||
|
(loop (add1 state)))))
|
||||||
|
(if (> SR-conflicts 0)
|
||||||
|
(fprintf (current-error-port)
|
||||||
|
"~a shift/reduce conflicts~n"
|
||||||
|
SR-conflicts))
|
||||||
|
(if (> RR-conflicts 0)
|
||||||
|
(fprintf (current-error-port)
|
||||||
|
"~a reduce/reduce conflicts~n"
|
||||||
|
RR-conflicts))))
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
(define (resolve-prec-conflicts table get-term get-prod
|
||||||
|
num-states num-terms num-non-terms)
|
||||||
|
(let loop ((state 0))
|
||||||
|
(if (< state num-states)
|
||||||
|
(begin
|
||||||
|
(let loop ((term 0))
|
||||||
|
(if (< term num-terms)
|
||||||
|
(begin
|
||||||
|
(let ((action (array2d-ref table
|
||||||
|
state
|
||||||
|
(+ num-non-terms term))))
|
||||||
|
(if (and (list? action)
|
||||||
|
(= 2 (length action))
|
||||||
|
(or (shift? (car action))
|
||||||
|
(shift? (cadr action))))
|
||||||
|
(let* ((shift (if (shift? (car action))
|
||||||
|
(car action)
|
||||||
|
(cadr action)))
|
||||||
|
(reduce (if (shift? (car action))
|
||||||
|
(cadr action)
|
||||||
|
(car action)))
|
||||||
|
(s-prec (term-prec
|
||||||
|
(vector-ref get-term
|
||||||
|
term)))
|
||||||
|
(r-prec (prod-prec
|
||||||
|
(vector-ref
|
||||||
|
get-prod
|
||||||
|
(reduce-prod-num reduce)))))
|
||||||
|
(if (and s-prec r-prec)
|
||||||
|
(array2d-set!
|
||||||
|
table
|
||||||
|
state
|
||||||
|
(+ num-non-terms term)
|
||||||
|
(cond
|
||||||
|
((< (prec-num s-prec)
|
||||||
|
(prec-num r-prec))
|
||||||
|
reduce)
|
||||||
|
((> (prec-num s-prec)
|
||||||
|
(prec-num r-prec))
|
||||||
|
shift)
|
||||||
|
((eq? 'left (prec-assoc s-prec))
|
||||||
|
reduce)
|
||||||
|
((eq? 'right (prec-assoc s-prec))
|
||||||
|
shift)
|
||||||
|
(else #f)))))))
|
||||||
|
(loop (add1 term)))))
|
||||||
|
(loop (add1 state))))))
|
||||||
|
|
||||||
|
;; In the result table the first index is the state and the second is the
|
||||||
|
;; term/non-term index (with the non-terms coming first)
|
||||||
|
;; buile-table: grammar * string -> action2d-array
|
||||||
|
(define (build-table g file)
|
||||||
|
(let* ((a (build-lr0-automaton g))
|
||||||
|
(terms (grammar-terms g))
|
||||||
|
(non-terms (grammar-non-terms g))
|
||||||
|
(get-state (lr0-states a))
|
||||||
|
(get-term (list->vector terms))
|
||||||
|
(get-non-term (list->vector non-terms))
|
||||||
|
(get-prod (list->vector (grammar-prods g)))
|
||||||
|
(num-states (vector-length get-state))
|
||||||
|
(num-terms (vector-length get-term))
|
||||||
|
(num-non-terms (vector-length get-non-term))
|
||||||
|
(num-gram-syms (+ num-terms num-non-terms))
|
||||||
|
(table (make-array2d num-states num-gram-syms #f))
|
||||||
|
(array2d-add!
|
||||||
|
(lambda (v i1 i2 a)
|
||||||
|
(let ((old (array2d-ref v i1 i2)))
|
||||||
|
(cond
|
||||||
|
((not old) (array2d-set! v i1 i2 a))
|
||||||
|
((list? old) (if (not (member a old))
|
||||||
|
(array2d-set! v i1 i2 (cons a old))))
|
||||||
|
(else (if (not (equal? a old))
|
||||||
|
(array2d-set! v i1 i2 (list a old))))))))
|
||||||
|
(get-lookahead (compute-LA a g)))
|
||||||
|
|
||||||
|
(let loop ((state 0))
|
||||||
|
(if (< state num-states)
|
||||||
|
(begin
|
||||||
|
(let loop ((i 0))
|
||||||
|
(if (< i num-gram-syms)
|
||||||
|
(begin
|
||||||
|
(let* ((s (if (< i num-non-terms)
|
||||||
|
(vector-ref get-non-term i)
|
||||||
|
(vector-ref get-term (- i num-non-terms))))
|
||||||
|
(goto
|
||||||
|
(run-automaton (vector-ref get-state state)
|
||||||
|
s
|
||||||
|
a)))
|
||||||
|
(if goto
|
||||||
|
(array2d-set! table
|
||||||
|
state
|
||||||
|
i
|
||||||
|
(if (< i num-non-terms)
|
||||||
|
(kernel-index goto)
|
||||||
|
(make-shift
|
||||||
|
(kernel-index goto))))))
|
||||||
|
(loop (add1 i)))))
|
||||||
|
(let ((items
|
||||||
|
(filter (lambda (item)
|
||||||
|
(not (move-dot-right item)))
|
||||||
|
(kernel-items
|
||||||
|
(vector-ref get-state state)))))
|
||||||
|
(for-each
|
||||||
|
(lambda (item)
|
||||||
|
(for-each
|
||||||
|
(lambda (t)
|
||||||
|
(array2d-add! table
|
||||||
|
state
|
||||||
|
(+ num-non-terms (gram-sym-index t))
|
||||||
|
(cond
|
||||||
|
((not (start-item? item))
|
||||||
|
(make-reduce
|
||||||
|
(item-prod-index item)
|
||||||
|
(gram-sym-index (prod-lhs (item-prod item)))
|
||||||
|
(vector-length (prod-rhs (item-prod item))))))))
|
||||||
|
(get-lookahead (vector-ref get-state state)
|
||||||
|
(item-prod item))))
|
||||||
|
items))
|
||||||
|
|
||||||
|
(loop (add1 state)))))
|
||||||
|
(resolve-prec-conflicts table get-term get-prod num-states num-terms
|
||||||
|
num-non-terms)
|
||||||
|
(if (not (string=? file ""))
|
||||||
|
(with-handlers [(exn:i/o:filesystem?
|
||||||
|
(lambda (e)
|
||||||
|
(fprintf
|
||||||
|
(current-error-port)
|
||||||
|
"Cannot write debug output to file \"~a\". ~a~n"
|
||||||
|
(exn:i/o:filesystem-pathname e)
|
||||||
|
(exn:i/o:filesystem-detail e))))]
|
||||||
|
(call-with-output-file file
|
||||||
|
(lambda (port)
|
||||||
|
(display-parser table get-term get-non-term get-state port)))))
|
||||||
|
(resolve-conflicts table num-states num-terms num-non-terms)
|
||||||
|
table))
|
||||||
|
)
|
||||||
|
|
||||||
@ -0,0 +1,35 @@
|
|||||||
|
#cs
|
||||||
|
(module terminal-syntax mzscheme
|
||||||
|
|
||||||
|
;; The things needed at compile time to handle definition of tokens
|
||||||
|
|
||||||
|
(provide make-terminals-def terminals-def-t terminals-def? define-tokens-helper)
|
||||||
|
|
||||||
|
(define-struct terminals-def (t))
|
||||||
|
|
||||||
|
(define (define-tokens-helper stx hack empty?)
|
||||||
|
(syntax-case stx ()
|
||||||
|
((_ name (terms ...))
|
||||||
|
(andmap identifier? (syntax->list (syntax (terms ...))))
|
||||||
|
(datum->syntax-object
|
||||||
|
hack
|
||||||
|
`(begin
|
||||||
|
(define-syntax ,(syntax name)
|
||||||
|
(make-terminals-def ',(syntax (terms ...))))
|
||||||
|
,@(map
|
||||||
|
(lambda (n)
|
||||||
|
`(define (,(datum->syntax-object
|
||||||
|
n
|
||||||
|
(string->symbol
|
||||||
|
(format "token-~a" (syntax-object->datum n)))
|
||||||
|
n)
|
||||||
|
,@(if empty? '() '(x)))
|
||||||
|
(make-token ',n ,(if empty? #f 'x))))
|
||||||
|
(syntax->list (syntax (terms ...)))))
|
||||||
|
stx))
|
||||||
|
((_ ...)
|
||||||
|
(raise-syntax-error
|
||||||
|
#f
|
||||||
|
"must have the form (define-tokens name (symbol ...))"
|
||||||
|
stx))))
|
||||||
|
)
|
||||||
@ -0,0 +1,24 @@
|
|||||||
|
#cs
|
||||||
|
(module terminal mzscheme
|
||||||
|
|
||||||
|
;; Defining tokens
|
||||||
|
|
||||||
|
(require-for-syntax "terminal-syntax.ss")
|
||||||
|
|
||||||
|
(provide define-tokens define-empty-tokens token-name token-value token?)
|
||||||
|
|
||||||
|
(define-struct token (name value))
|
||||||
|
|
||||||
|
(define-syntax define-tokens
|
||||||
|
(lambda (stx)
|
||||||
|
(syntax-case stx ()
|
||||||
|
((_ name ...)
|
||||||
|
(define-tokens-helper stx #'hack #f)))))
|
||||||
|
|
||||||
|
(define-syntax define-empty-tokens
|
||||||
|
(lambda (stx)
|
||||||
|
(syntax-case stx ()
|
||||||
|
((_ name ...)
|
||||||
|
(define-tokens-helper stx #'hack #t)))))
|
||||||
|
)
|
||||||
|
|
||||||
@ -0,0 +1,63 @@
|
|||||||
|
#cs
|
||||||
|
(module yacc-helper mzscheme
|
||||||
|
|
||||||
|
;; General helper routines
|
||||||
|
|
||||||
|
(provide duplicate-list? remove-duplicates overlap? vector-andmap)
|
||||||
|
|
||||||
|
(define (vector-andmap f v)
|
||||||
|
(let loop ((i 0))
|
||||||
|
(cond
|
||||||
|
((= i (vector-length v)) #t)
|
||||||
|
(else (if (f (vector-ref v i))
|
||||||
|
(loop (add1 i))
|
||||||
|
#f)))))
|
||||||
|
|
||||||
|
;; duplicate-list?: symbol list -> #f | symbol
|
||||||
|
;; returns a symbol that exists twice in l, or false if no such symbol
|
||||||
|
;; exists
|
||||||
|
(define (duplicate-list? l)
|
||||||
|
(letrec ((t (make-hash-table))
|
||||||
|
(dl? (lambda (l)
|
||||||
|
(cond
|
||||||
|
((null? l) #f)
|
||||||
|
((hash-table-get t (car l) (lambda () #f)) =>
|
||||||
|
(lambda (x) x))
|
||||||
|
(else
|
||||||
|
(hash-table-put! t (car l) (car l))
|
||||||
|
(dl? (cdr l)))))))
|
||||||
|
(dl? l)))
|
||||||
|
|
||||||
|
;; remove-duplicates: symbol list -> symbol list
|
||||||
|
;; removes the duplicates from the lists
|
||||||
|
(define (remove-duplicates sl)
|
||||||
|
(let ((t (make-hash-table)))
|
||||||
|
(letrec ((x
|
||||||
|
(lambda (sl)
|
||||||
|
(cond
|
||||||
|
((null? sl) sl)
|
||||||
|
((hash-table-get t (car sl) (lambda () #f))
|
||||||
|
(x (cdr sl)))
|
||||||
|
(else
|
||||||
|
(hash-table-put! t (car sl) #t)
|
||||||
|
(cons (car sl) (x (cdr sl))))))))
|
||||||
|
(x sl))))
|
||||||
|
|
||||||
|
;; overlap?: symbol list * symbol list -> #f | symbol
|
||||||
|
;; Returns an symbol in l1 intersect l2, or #f is no such symbol exists
|
||||||
|
(define (overlap? l1 l2)
|
||||||
|
(let/ec ret
|
||||||
|
(let ((t (make-hash-table)))
|
||||||
|
(for-each (lambda (s1)
|
||||||
|
(hash-table-put! t s1 s1))
|
||||||
|
l1)
|
||||||
|
(for-each (lambda (s2)
|
||||||
|
(cond
|
||||||
|
((hash-table-get t s2 (lambda () #f)) =>
|
||||||
|
(lambda (o) (ret o)))))
|
||||||
|
l2)
|
||||||
|
#f)))
|
||||||
|
|
||||||
|
|
||||||
|
)
|
||||||
|
|
||||||
@ -0,0 +1,40 @@
|
|||||||
|
#cs
|
||||||
|
(module yacc mzscheme
|
||||||
|
|
||||||
|
(require-for-syntax "private-yacc/parser-builder.ss")
|
||||||
|
(require "private-yacc/terminal.ss"
|
||||||
|
"private-yacc/parser-actions.ss"
|
||||||
|
"private-yacc/array2d.ss")
|
||||||
|
|
||||||
|
(provide define-tokens define-empty-tokens parser parser-debug)
|
||||||
|
|
||||||
|
(define-syntax parser
|
||||||
|
(lambda (stx)
|
||||||
|
(syntax-case stx ()
|
||||||
|
((_ start input-terms assocs prods)
|
||||||
|
(build-parser (syntax start) (syntax input-terms)
|
||||||
|
(syntax assocs) (syntax prods)
|
||||||
|
"" #'here stx))
|
||||||
|
(_
|
||||||
|
(raise-syntax-error
|
||||||
|
#f
|
||||||
|
"parser must have the form (parser start-symbol tokens precedence/associativity productions)"
|
||||||
|
stx)))))
|
||||||
|
|
||||||
|
|
||||||
|
(define-syntax parser-debug
|
||||||
|
(lambda (stx)
|
||||||
|
(syntax-case stx ()
|
||||||
|
((_ filename start input-terms assocs prods)
|
||||||
|
(string? (syntax-object->datum (syntax filename)))
|
||||||
|
(build-parser (syntax start) (syntax input-terms)
|
||||||
|
(syntax assocs) (syntax prods)
|
||||||
|
(syntax-object->datum (syntax filename))
|
||||||
|
#'here stx))
|
||||||
|
(_
|
||||||
|
(raise-syntax-error
|
||||||
|
#f
|
||||||
|
"parser must have the form (parser-debug filename start-symbol tokens precedence/associativity productions) where filename is a string"
|
||||||
|
stx)))))
|
||||||
|
|
||||||
|
)
|
||||||
Loading…
Reference in New Issue