@ -62,9 +62,9 @@
;; (listof (cons/c trans-key? (listof kernel?)))
;; (listof (cons/c trans-key? (listof kernel?)))
( define ( reverse-assoc assoc )
( define ( reverse-assoc assoc )
( let ( ( reverse-hash ( make-hash-table ' equal ) )
( let ( ( reverse-hash ( make-hash-table ' equal ) )
( hash-table-add!
( hash-table-add!
( lambda ( ht k v )
( lambda ( ht k v )
( hash-table-put! ht k ( cons v ( hash-table-get ht k ( lambda ( ) null ) ) ) ) ) ) )
( hash-table-put! ht k ( cons v ( hash-table-get ht k ( lambda ( ) null ) ) ) ) ) ) )
( for-each
( for-each
( lambda ( trans-key/kernel )
( lambda ( trans-key/kernel )
( let ( ( tk ( car trans-key/kernel ) ) )
( let ( ( tk ( car trans-key/kernel ) ) )
@ -99,13 +99,13 @@
( define mapped-non-terms ( map car non-term-assoc ) )
( define mapped-non-terms ( map car non-term-assoc ) )
( define/public ( get-mapped-non-term-keys )
( define/public ( get-mapped-non-term-keys )
mapped-non-terms )
mapped-non-terms )
( define/public ( get-num-states )
( define/public ( get-num-states )
( vector-length states ) )
( vector-length states ) )
( define/public ( get-epsilon-trans )
( define/public ( get-epsilon-trans )
epsilons )
epsilons )
( define/public ( get-transitions )
( define/public ( get-transitions )
( append term-assoc non-term-assoc ) )
( append term-assoc non-term-assoc ) )
@ -113,12 +113,12 @@
;; for-each-state : (state ->) ->
;; for-each-state : (state ->) ->
;; Iteration over the states in an automaton
;; Iteration over the states in an automaton
( define/public ( for-each-state f )
( define/public ( for-each-state f )
( let ( ( num-states ( vector-length states ) ) )
( let ( ( num-states ( vector-length states ) ) )
( let loop ( ( i 0 ) )
( let loop ( ( i 0 ) )
( if ( < i num-states )
( if ( < i num-states )
( begin
( begin
( f ( vector-ref states i ) )
( f ( vector-ref states i ) )
( loop ( add1 i ) ) ) ) ) ) )
( loop ( add1 i ) ) ) ) ) ) )
;; run-automaton: kernel? gram-sym? -> (union kernel #f)
;; run-automaton: kernel? gram-sym? -> (union kernel #f)
;; returns the state reached from state k on input s, or #f when k
;; returns the state reached from state k on input s, or #f when k
@ -131,28 +131,28 @@
;; run-automaton-back : (listof kernel?) gram-sym? -> (listof kernel)
;; run-automaton-back : (listof kernel?) gram-sym? -> (listof kernel)
;; returns the list of states that can reach k by transitioning on s.
;; returns the list of states that can reach k by transitioning on s.
( define/public ( run-automaton-back k s )
( define/public ( run-automaton-back k s )
( apply append
( apply append
( map
( map
( lambda ( k )
( lambda ( k )
( hash-table-get ( vector-ref reverse-transitions ( kernel-index k ) )
( hash-table-get ( vector-ref reverse-transitions ( kernel-index k ) )
( gram-sym-symbol s )
( gram-sym-symbol s )
( lambda ( ) null ) ) )
( lambda ( ) null ) ) )
k ) ) ) ) )
k ) ) ) ) )
( define ( union comp<? )
( define ( union comp<? )
( letrec ( ( union
( letrec ( ( union
( lambda ( l1 l2 )
( lambda ( l1 l2 )
( cond
( cond
( ( null? l1 ) l2 )
( ( null? l1 ) l2 )
( ( null? l2 ) l1 )
( ( null? l2 ) l1 )
( else ( let ( ( c1 ( car l1 ) )
( else ( let ( ( c1 ( car l1 ) )
( c2 ( car l2 ) ) )
( c2 ( car l2 ) ) )
( cond
( cond
( ( comp<? c1 c2 )
( ( comp<? c1 c2 )
( cons c1 ( union ( cdr l1 ) l2 ) ) )
( cons c1 ( union ( cdr l1 ) l2 ) ) )
( ( comp<? c2 c1 )
( ( comp<? c2 c1 )
( cons c2 ( union l1 ( cdr l2 ) ) ) )
( cons c2 ( union l1 ( cdr l2 ) ) ) )
( else ( union ( cdr l1 ) l2 ) ) ) ) ) ) ) ) )
( else ( union ( cdr l1 ) l2 ) ) ) ) ) ) ) ) )
union ) )
union ) )
@ -160,141 +160,141 @@
;; That is (equal? a b) <=> (eq? a b)
;; That is (equal? a b) <=> (eq? a b)
( define ( kernel->string k )
( define ( kernel->string k )
( apply string-append
( apply string-append
` ( " { " ,@ ( map ( lambda ( i ) ( string-append ( item->string i ) " , " ) )
` ( " { " ,@ ( map ( lambda ( i ) ( string-append ( item->string i ) " , " ) )
( kernel-items k ) )
( kernel-items k ) )
" } " ) ) )
" } " ) ) )
;; build-LR0-automaton: grammar -> LR0-automaton
;; build-LR0-automaton: grammar -> LR0-automaton
;; Constructs the kernels of the sets of LR(0) items of g
;; Constructs the kernels of the sets of LR(0) items of g
( define ( build-lr0-automaton grammar )
( define ( build-lr0-automaton grammar )
; (printf "LR(0) automaton:\n")
; (printf "LR(0) automaton:\n")
( letrec (
( letrec (
( epsilons ( make-hash-table ' equal ) )
( epsilons ( make-hash-table ' equal ) )
( grammar-symbols ( append ( send grammar get-non-terms )
( grammar-symbols ( append ( send grammar get-non-terms )
( send grammar get-terms ) ) )
( send grammar get-terms ) ) )
;; first-non-term: non-term -> non-term list
;; first-non-term: non-term -> non-term list
;; given a non-terminal symbol C, return those non-terminal
;; given a non-terminal symbol C, return those non-terminal
;; symbols A s.t. C -> An for some string of terminals and
;; symbols A s.t. C -> An for some string of terminals and
;; non-terminals n where -> means a rightmost derivation in many
;; non-terminals n where -> means a rightmost derivation in many
;; steps. Assumes that each non-term can be reduced to a string
;; steps. Assumes that each non-term can be reduced to a string
;; of terms.
;; of terms.
( first-non-term
( first-non-term
( digraph ( send grammar get-non-terms )
( digraph ( send grammar get-non-terms )
( lambda ( nt )
( lambda ( nt )
( filter non-term?
( filter non-term?
( map ( lambda ( prod )
( map ( lambda ( prod )
( sym-at-dot ( make-item prod 0 ) ) )
( sym-at-dot ( make-item prod 0 ) ) )
( send grammar get-prods-for-non-term nt ) ) ) )
( send grammar get-prods-for-non-term nt ) ) ) )
( lambda ( nt ) ( list nt ) )
( lambda ( nt ) ( list nt ) )
( union non-term<? )
( union non-term<? )
( lambda ( ) null ) ) )
( lambda ( ) null ) ) )
;; closure: LR1-item list -> LR1-item list
;; closure: LR1-item list -> LR1-item list
;; Creates a set of items containing i s.t. if A -> n.Xm is in it,
;; Creates a set of items containing i s.t. if A -> n.Xm is in it,
;; X -> .o is in it too.
;; X -> .o is in it too.
( LR0-closure
( LR0-closure
( lambda ( i )
( lambda ( i )
( cond
( cond
( ( null? i ) null )
( ( null? i ) null )
( else
( else
( let ( ( next-gsym ( sym-at-dot ( car i ) ) ) )
( let ( ( next-gsym ( sym-at-dot ( car i ) ) ) )
( cond
( cond
( ( non-term? next-gsym )
( ( non-term? next-gsym )
( cons ( car i )
( cons ( car i )
( append
( append
( apply append
( apply append
( map ( lambda ( non-term )
( map ( lambda ( non-term )
( map ( lambda ( x )
( map ( lambda ( x )
( make-item x 0 ) )
( make-item x 0 ) )
( send grammar
( send grammar
get-prods-for-non-term
get-prods-for-non-term
non-term ) ) )
non-term ) ) )
( first-non-term next-gsym ) ) )
( first-non-term next-gsym ) ) )
( LR0-closure ( cdr i ) ) ) ) )
( LR0-closure ( cdr i ) ) ) ) )
( else
( else
( cons ( car i ) ( LR0-closure ( cdr i ) ) ) ) ) ) ) ) ) )
( cons ( car i ) ( LR0-closure ( cdr i ) ) ) ) ) ) ) ) ) )
;; maps trans-keys to kernels
;; maps trans-keys to kernels
( automaton-term null )
( automaton-term null )
( automaton-non-term null )
( automaton-non-term null )
;; keeps the kernels we have seen, so we can have a unique
;; keeps the kernels we have seen, so we can have a unique
;; list for each kernel
;; list for each kernel
( kernels ( make-hash-table ' equal ) )
( kernels ( make-hash-table ' equal ) )
( counter 0 )
( counter 0 )
;; goto: LR1-item list -> LR1-item list list
;; goto: LR1-item list -> LR1-item list list
;; creates new kernels by moving the dot in each item in the
;; creates new kernels by moving the dot in each item in the
;; LR0-closure of kernel to the right, and grouping them by
;; LR0-closure of kernel to the right, and grouping them by
;; the term/non-term moved over. Returns the kernels not
;; the term/non-term moved over. Returns the kernels not
;; yet seen, and places the trans-keys into automaton
;; yet seen, and places the trans-keys into automaton
( goto
( goto
( lambda ( kernel )
( lambda ( kernel )
( let (
( let (
;; maps a gram-syms to a list of items
;; maps a gram-syms to a list of items
( table ( make-hash-table ) )
( table ( make-hash-table ) )
;; add-item!:
;; add-item!:
;; (symbol (listof item) hashtable) item? ->
;; (symbol (listof item) hashtable) item? ->
;; adds i into the table grouped with the grammar
;; adds i into the table grouped with the grammar
;; symbol following its dot
;; symbol following its dot
( add-item!
( add-item!
( lambda ( table i )
( lambda ( table i )
( let ( ( gs ( sym-at-dot i ) ) )
( let ( ( gs ( sym-at-dot i ) ) )
( cond
( cond
( gs
( gs
( let ( ( already
( let ( ( already
( hash-table-get table
( hash-table-get table
( gram-sym-symbol gs )
( gram-sym-symbol gs )
( lambda ( ) null ) ) ) )
( lambda ( ) null ) ) ) )
( unless ( member i already )
( unless ( member i already )
( hash-table-put! table
( hash-table-put! table
( gram-sym-symbol gs )
( gram-sym-symbol gs )
( cons i already ) ) ) ) )
( cons i already ) ) ) ) )
( ( = 0 ( vector-length ( prod-rhs ( item-prod i ) ) ) )
( ( = 0 ( vector-length ( prod-rhs ( item-prod i ) ) ) )
( let ( ( current ( hash-table-get epsilons
( let ( ( current ( hash-table-get epsilons
kernel
kernel
( lambda ( ) null ) ) ) )
( lambda ( ) null ) ) ) )
( hash-table-put! epsilons
( hash-table-put! epsilons
kernel
kernel
( cons i current ) ) ) ) ) ) ) ) )
( cons i current ) ) ) ) ) ) ) ) )
;; Group the items of the LR0 closure of the kernel
;; Group the items of the LR0 closure of the kernel
;; by the character after the dot
;; by the character after the dot
( for-each ( lambda ( item )
( for-each ( lambda ( item )
( add-item! table item ) )
( add-item! table item ) )
( LR0-closure ( kernel-items kernel ) ) )
( LR0-closure ( kernel-items kernel ) ) )
;; each group is a new kernel, with the dot advanced.
;; each group is a new kernel, with the dot advanced.
;; sorts the items in a kernel so kernels can be compared
;; sorts the items in a kernel so kernels can be compared
;; with equal? for using the table kernels to make sure
;; with equal? for using the table kernels to make sure
;; only one representitive of each kernel is created
;; only one representitive of each kernel is created
( filter
( filter
( lambda ( x ) x )
( lambda ( x ) x )
( map
( map
( lambda ( i )
( lambda ( i )
( let* ( ( gs ( car i ) )
( let* ( ( gs ( car i ) )
( items ( cadr i ) )
( items ( cadr i ) )
( new #f )
( new #f )
( new-kernel ( sort
( new-kernel ( sort
( filter ( lambda ( x ) x )
( filter ( lambda ( x ) x )
( map move-dot-right items ) )
( map move-dot-right items ) )
item<? ) )
item<? ) )
( unique-kernel ( hash-table-get
( unique-kernel ( hash-table-get
kernels
kernels
new-kernel
new-kernel
( lambda ( )
( lambda ( )
( let ( ( k ( make-kernel
( let ( ( k ( make-kernel
new-kernel
new-kernel
counter ) ) )
counter ) ) )
( set! new #t )
( set! new #t )
( set! counter ( add1 counter ) )
( set! counter ( add1 counter ) )
( hash-table-put! kernels
( hash-table-put! kernels
new-kernel
new-kernel
k )
k )
k ) ) ) ) )
k ) ) ) ) )
( cond
( cond
( ( term? gs )
( ( term? gs )
( set! automaton-term ( cons ( cons ( make-trans-key kernel gs )
( set! automaton-term ( cons ( cons ( make-trans-key kernel gs )
@ -305,14 +305,14 @@
unique-kernel )
unique-kernel )
automaton-non-term ) ) ) )
automaton-non-term ) ) ) )
#; ( printf " ~a -> ~a on ~a \n "
#; ( printf " ~a -> ~a on ~a \n "
( kernel->string kernel )
( kernel->string kernel )
( kernel->string unique-kernel )
( kernel->string unique-kernel )
( gram-sym-symbol gs ) )
( gram-sym-symbol gs ) )
( if new
( if new
unique-kernel
unique-kernel
#f ) ) )
#f ) ) )
( let loop ( ( gsyms grammar-symbols ) )
( let loop ( ( gsyms grammar-symbols ) )
( cond
( cond
( ( null? gsyms ) null )
( ( null? gsyms ) null )
( else
( else
( let ( ( items ( hash-table-get table
( let ( ( items ( hash-table-get table
@ -323,33 +323,33 @@
( else
( else
( cons ( list ( car gsyms ) items )
( cons ( list ( car gsyms ) items )
( loop ( cdr gsyms ) ) ) ) ) ) ) ) ) ) ) ) ) )
( loop ( cdr gsyms ) ) ) ) ) ) ) ) ) ) ) ) ) )
( starts
( starts
( map ( lambda ( init-prod ) ( list ( make-item init-prod 0 ) ) )
( map ( lambda ( init-prod ) ( list ( make-item init-prod 0 ) ) )
( send grammar get-init-prods ) ) )
( send grammar get-init-prods ) ) )
( startk
( startk
( map ( lambda ( start )
( map ( lambda ( start )
( let ( ( k ( make-kernel start counter ) ) )
( let ( ( k ( make-kernel start counter ) ) )
( hash-table-put! kernels start k )
( hash-table-put! kernels start k )
( set! counter ( add1 counter ) )
( set! counter ( add1 counter ) )
k ) )
k ) )
starts ) )
starts ) )
( new-kernels ( make-queue ) ) )
( new-kernels ( make-queue ) ) )
( let loop ( ( old-kernels startk )
( let loop ( ( old-kernels startk )
( seen-kernels null ) )
( seen-kernels null ) )
( cond
( cond
( ( and ( empty-queue? new-kernels ) ( null? old-kernels ) )
( ( and ( empty-queue? new-kernels ) ( null? old-kernels ) )
( make-object lr0%
( make-object lr0%
automaton-term
automaton-term
automaton-non-term
automaton-non-term
( list->vector ( reverse seen-kernels ) )
( list->vector ( reverse seen-kernels ) )
epsilons ) )
epsilons ) )
( ( null? old-kernels )
( ( null? old-kernels )
( loop ( deq! new-kernels ) seen-kernels ) )
( loop ( deq! new-kernels ) seen-kernels ) )
( else
( else
( enq! new-kernels ( goto ( car old-kernels ) ) )
( enq! new-kernels ( goto ( car old-kernels ) ) )
( loop ( cdr old-kernels ) ( cons ( car old-kernels ) seen-kernels ) ) ) ) ) ) )
( loop ( cdr old-kernels ) ( cons ( car old-kernels ) seen-kernels ) ) ) ) ) ) )
( define-struct q ( f l ) ( make-inspector ) )
( define-struct q ( f l ) ( make-inspector ) )
( define ( empty-queue? q )
( define ( empty-queue? q )
@ -358,12 +358,12 @@
( make-q null null ) )
( make-q null null ) )
( define ( enq! q i )
( define ( enq! q i )
( if ( empty-queue? q )
( if ( empty-queue? q )
( let ( ( i ( mcons i null ) ) )
( let ( ( i ( mcons i null ) ) )
( set-q-l! q i )
( set-q-l! q i )
( set-q-f! q i ) )
( set-q-f! q i ) )
( begin
( begin
( set-mcdr! ( q-l q ) ( mcons i null ) )
( set-mcdr! ( q-l q ) ( mcons i null ) )
( set-q-l! q ( mcdr ( q-l q ) ) ) ) ) )
( set-q-l! q ( mcdr ( q-l q ) ) ) ) ) )
( define ( deq! q )
( define ( deq! q )
( begin0
( begin0
( mcar ( q-f q ) )
( mcar ( q-f q ) )