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Unify syntax/datum labels as semantic actions

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remotes/jackfirth/master
Jack Firth 3 years ago
parent 31174e67f4
commit 2e53bca272
3 changed files with 94 additions and 93 deletions
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123
base/derivation.rkt
Unescape Escape View File

@ -7,7 +7,6 @@
(provide (provide
(struct-out terminal-derivation) (struct-out terminal-derivation)
(struct-out nonterminal-derivation) (struct-out nonterminal-derivation)
(struct-out datum-label)
(contract-out (contract-out
[parser-derivation? predicate/c] [parser-derivation? predicate/c]
[parser-derivation-first-terminal (-> parser-derivation? any/c)] [parser-derivation-first-terminal (-> parser-derivation? any/c)]
@ -15,19 +14,19 @@
[parser-derivation [parser-derivation
(case-> (case->
(-> any/c terminal-derivation?) (-> any/c terminal-derivation?)
(-> derivation-label? parser-derivation? #:rest (listof parser-derivation?) (-> semantic-action? parser-derivation? #:rest (listof parser-derivation?)
nonterminal-derivation?))] nonterminal-derivation?))]
[parser-derivation->syntax (-> parser-derivation? syntax?)] [parser-derivation->syntax (-> parser-derivation? syntax?)]
[derivation-label? predicate/c] [semantic-action? predicate/c]
[cut-label cut-label?] [cut-action cut-action?]
[cut-label? predicate/c] [cut-action? predicate/c]
[splice-label splice-label?] [splice-action splice-action?]
[splice-label? predicate/c] [splice-action? predicate/c]
[syntax-label? predicate/c] [label-action? predicate/c]
[syntax-label (->* (any/c) (#:properties hash? #:expression-properties hash?) syntax-label?)] [label-action (->* (any/c) (#:properties hash? #:expression-properties hash?) label-action?)]
[syntax-label-value (-> syntax-label? any/c)] [label-action-value (-> label-action? any/c)]
[syntax-label-properties (-> syntax-label? hash?)] [label-action-properties (-> label-action? hash?)]
[syntax-label-expression-properties (-> syntax-label? hash?)])) [label-action-expression-properties (-> label-action? hash?)]))
(require racket/match (require racket/match
@ -56,16 +55,17 @@
(struct terminal-derivation (value) #:transparent) (struct terminal-derivation (value) #:transparent)
;; A (Nonterminal-Derivation V L) represents a nonterminal that was matched by the grammar. It ;; A (Nonterminal-Derivation V A) represents a nonterminal that was matched by the grammar. It
;; contains the label of type L of the production rule that matched, and an immutable vector of ;; contains the action of type (Semantic-Action A) of the production rule that matched, and an
;; subderivations ;; immutable vector of subderivations
(struct nonterminal-derivation (label children) (struct nonterminal-derivation (action children)
#:guard #:guard
(let ([contract-guard (struct-guard/c any/c (sequence/c parser-derivation? #:min-count 1))]) (let ([contract-guard
(λ (label children name) (struct-guard/c semantic-action? (sequence/c parser-derivation? #:min-count 1))])
(let-values ([(label children) (contract-guard label children name)]) (λ (action children name)
(values label (sequence->vector children))))) (let-values ([(action children) (contract-guard action children name)])
(values action (sequence->vector children)))))
#:transparent #:transparent
#:property prop:custom-print-quotable 'never #:property prop:custom-print-quotable 'never
@ -74,14 +74,14 @@
(make-constructor-style-printer (make-constructor-style-printer
(λ (_) 'nonterminal-derivation) (λ (_) 'nonterminal-derivation)
(λ (this) (λ (this)
(cons (nonterminal-derivation-label this) (cons (nonterminal-derivation-action this)
(vector->list (nonterminal-derivation-children this))))))]) (vector->list (nonterminal-derivation-children this))))))])
(define parser-derivation (define parser-derivation
(case-lambda (case-lambda
[(value) (terminal-derivation value)] [(value) (terminal-derivation value)]
[(label first-child . children) (nonterminal-derivation label (cons first-child children))])) [(action first-child . children) (nonterminal-derivation action (cons first-child children))]))
(define (parser-derivation-first-terminal derivation) (define (parser-derivation-first-terminal derivation)
@ -107,7 +107,7 @@
(test-case "nonterminal of terminals" (test-case "nonterminal of terminals"
(define derivation (define derivation
(parser-derivation (parser-derivation
(datum-label 'a) (label-action 'a)
(parser-derivation 1) (parser-derivation 1)
(parser-derivation 2) (parser-derivation 2)
(parser-derivation 3))) (parser-derivation 3)))
@ -116,8 +116,8 @@
(test-case "nonterminal of nonterminals and terminals" (test-case "nonterminal of nonterminals and terminals"
(define derivation (define derivation
(parser-derivation (parser-derivation
(datum-label 'a) (label-action 'a)
(parser-derivation (datum-label 'b) (parser-derivation 1)) (parser-derivation (label-action 'b) (parser-derivation 1))
(parser-derivation 2) (parser-derivation 2)
(parser-derivation 3))) (parser-derivation 3)))
(check-equal? (parser-derivation-first-terminal derivation) 1))) (check-equal? (parser-derivation-first-terminal derivation) 1)))
@ -130,7 +130,7 @@
(test-case "nonterminal of terminals" (test-case "nonterminal of terminals"
(define derivation (define derivation
(parser-derivation (parser-derivation
(datum-label 'a) (label-action 'a)
(parser-derivation 1) (parser-derivation 1)
(parser-derivation 2) (parser-derivation 2)
(parser-derivation 3))) (parser-derivation 3)))
@ -139,31 +139,29 @@
(test-case "nonterminal of nonterminals and terminals" (test-case "nonterminal of nonterminals and terminals"
(define derivation (define derivation
(parser-derivation (parser-derivation
(datum-label 'a) (label-action 'a)
(parser-derivation 1) (parser-derivation 1)
(parser-derivation 2) (parser-derivation 2)
(parser-derivation (datum-label 'b) (parser-derivation 3)))) (parser-derivation (label-action 'b) (parser-derivation 3))))
(check-equal? (parser-derivation-last-terminal derivation) 3)))) (check-equal? (parser-derivation-last-terminal derivation) 3))))
(define (derivation-label? v) (define (semantic-action? v)
(or (cut-label? v) (splice-label? v) (datum-label? v) (syntax-label? v))) (or (cut-action? v) (splice-action? v) (label-action? v)))
(struct cut-label () #:transparent #:constructor-name constructor:cut-label #:omit-define-syntaxes) (struct cut-action () #:transparent #:constructor-name constructor:cut-action #:omit-define-syntaxes)
(define cut-label (constructor:cut-label)) (define cut-action (constructor:cut-action))
(struct splice-label () (struct splice-action ()
#:transparent #:constructor-name constructor:splice-label #:omit-define-syntaxes) #:transparent #:constructor-name constructor:splice-action #:omit-define-syntaxes)
(define splice-label (constructor:splice-label)) (define splice-action (constructor:splice-action))
(struct datum-label (value) #:transparent) (struct label-action (value expression-properties properties)
(struct syntax-label (value expression-properties properties)
#:transparent #:transparent
#:constructor-name constructor:syntax-label #:constructor-name constructor:label-action
#:omit-define-syntaxes #:omit-define-syntaxes
#:guard #:guard
(struct-guard/c any/c (struct-guard/c any/c
@ -171,22 +169,22 @@
(hash/c any/c any/c #:immutable #true #:flat? #true))) (hash/c any/c any/c #:immutable #true #:flat? #true)))
(define (syntax-label value (define (label-action value
#:properties [properties (hash)] #:properties [properties (hash)]
#:expression-properties [expression-properties (hash)]) #:expression-properties [expression-properties (hash)])
(constructor:syntax-label value properties expression-properties)) (constructor:label-action value properties expression-properties))
(define (parser-derivation->syntax derivation) (define (parser-derivation->syntax derivation)
(define (->splice derivation) (define (->splice derivation)
(match derivation (match derivation
[(terminal-derivation t) (list (syntax-token->syntax t))] [(terminal-derivation t) (list (syntax-token->syntax t))]
[(nonterminal-derivation (? cut-label?) _) '()] [(nonterminal-derivation (? cut-action?) _) '()]
[(nonterminal-derivation (? splice-label?) children) [(nonterminal-derivation (? splice-action?) children)
(for*/list ([child (in-vector children)] (for*/list ([child (in-vector children)]
[stx (in-list (->splice child))]) [stx (in-list (->splice child))])
stx)] stx)]
[(nonterminal-derivation (? syntax-label? label) children) [(nonterminal-derivation (? label-action? label) children)
(define first-token (parser-derivation-first-terminal derivation)) (define first-token (parser-derivation-first-terminal derivation))
(define label-location (define label-location
(srcloc (syntax-token-source first-token) (srcloc (syntax-token-source first-token)
@ -195,8 +193,8 @@
(syntax-token-position first-token) (syntax-token-position first-token)
0)) 0))
(define label-stx (define label-stx
(for/fold ([stx (datum->syntax #false (syntax-label-value label) label-location #false)]) (for/fold ([stx (datum->syntax #false (label-action-value label) label-location #false)])
([(key value) (in-hash (syntax-label-properties label))]) ([(key value) (in-hash (label-action-properties label))])
(syntax-property stx key value))) (syntax-property stx key value)))
(define children-syntaxes (define children-syntaxes
(for*/list ([child (in-vector children)] (for*/list ([child (in-vector children)]
@ -212,7 +210,7 @@
(define expression-stx (define expression-stx
(datum->syntax #false (cons label-stx children-syntaxes) expression-location #false)) (datum->syntax #false (cons label-stx children-syntaxes) expression-location #false))
(list (for/fold ([expression-stx expression-stx]) (list (for/fold ([expression-stx expression-stx])
([(key value) (in-hash (syntax-label-expression-properties label))]) ([(key value) (in-hash (label-action-expression-properties label))])
(syntax-property expression-stx key value)))])) (syntax-property expression-stx key value)))]))
(define first-token (parser-derivation-first-terminal derivation)) (define first-token (parser-derivation-first-terminal derivation))
(define last-token (parser-derivation-last-terminal derivation)) (define last-token (parser-derivation-last-terminal derivation))
@ -231,12 +229,13 @@
(define (->splice derivation) (define (->splice derivation)
(match derivation (match derivation
[(terminal-derivation t) (list t)] [(terminal-derivation t) (list t)]
[(nonterminal-derivation (? cut-label?) _) '()] [(nonterminal-derivation (? cut-action?) _) '()]
[(nonterminal-derivation (? splice-label?) children) [(nonterminal-derivation (? splice-action?) children)
(for*/list ([child (in-vector children)] (for*/list ([child (in-vector children)]
[datum (in-list (->splice child))]) [datum (in-list (->splice child))])
datum)] datum)]
[(nonterminal-derivation (datum-label value) children) [(nonterminal-derivation (? label-action? label) children)
(define value (label-action-value label))
(define child-data (define child-data
(for*/list ([child (in-vector children)] (for*/list ([child (in-vector children)]
[spliced-child (in-list (->splice child))]) [spliced-child (in-list (->splice child))])
@ -256,7 +255,7 @@
(test-case "datum nonterminals" (test-case "datum nonterminals"
(define derivation (define derivation
(parser-derivation (datum-label 'a) (parser-derivation (label-action 'a)
(parser-derivation 'b) (parser-derivation 'b)
(parser-derivation 'c) (parser-derivation 'c)
(parser-derivation 'd))) (parser-derivation 'd)))
@ -264,17 +263,17 @@
(test-case "datum cuts" (test-case "datum cuts"
(define derivation (define derivation
(parser-derivation (datum-label 'a) (parser-derivation (label-action 'a)
(parser-derivation cut-label (parser-derivation 'b)) (parser-derivation cut-action (parser-derivation 'b))
(parser-derivation 'c) (parser-derivation 'c)
(parser-derivation cut-label (parser-derivation 'd)))) (parser-derivation cut-action (parser-derivation 'd))))
(check-equal? (parser-derivation->datum derivation) '(a c))) (check-equal? (parser-derivation->datum derivation) '(a c)))
(test-case "datum splices" (test-case "datum splices"
(define derivation (define derivation
(parser-derivation (datum-label 'a) (parser-derivation (label-action 'a)
(parser-derivation 'b) (parser-derivation 'b)
(parser-derivation splice-label (parser-derivation splice-action
(parser-derivation 'c1) (parser-derivation 'c1)
(parser-derivation 'c2) (parser-derivation 'c2)
(parser-derivation 'c3)) (parser-derivation 'c3))
@ -292,7 +291,7 @@
(test-case "syntax nonterminals" (test-case "syntax nonterminals"
(define derivation (define derivation
(parser-derivation (parser-derivation
(syntax-label 'a) (label-action 'a)
(parser-derivation (syntax-token 'b #:position 1 #:span 1)) (parser-derivation (syntax-token 'b #:position 1 #:span 1))
(parser-derivation (syntax-token 'c #:position 2 #:span 1)) (parser-derivation (syntax-token 'c #:position 2 #:span 1))
(parser-derivation (syntax-token 'd #:position 3 #:span 1)))) (parser-derivation (syntax-token 'd #:position 3 #:span 1))))
@ -303,10 +302,10 @@
(test-case "syntax cuts" (test-case "syntax cuts"
(define derivation (define derivation
(parser-derivation (parser-derivation
(syntax-label 'a) (label-action 'a)
(parser-derivation cut-label (parser-derivation (syntax-token 'b #:position 1 #:span 1))) (parser-derivation cut-action (parser-derivation (syntax-token 'b #:position 1 #:span 1)))
(parser-derivation (syntax-token 'c #:position 2 #:span 1)) (parser-derivation (syntax-token 'c #:position 2 #:span 1))
(parser-derivation cut-label (parser-derivation (syntax-token 'd #:position 3 #:span 1))))) (parser-derivation cut-action (parser-derivation (syntax-token 'd #:position 3 #:span 1)))))
(define actual (parser-derivation->syntax derivation)) (define actual (parser-derivation->syntax derivation))
(check-equal? (syntax->datum actual) '(a c)) (check-equal? (syntax->datum actual) '(a c))
(check-equal? (syntax-srcloc actual) (srcloc #false #false #false 1 3))) (check-equal? (syntax-srcloc actual) (srcloc #false #false #false 1 3)))
@ -314,9 +313,9 @@
(test-case "syntax splices" (test-case "syntax splices"
(define derivation (define derivation
(parser-derivation (parser-derivation
(syntax-label 'a) (label-action 'a)
(parser-derivation (syntax-token 'b #:position 1 #:span 1)) (parser-derivation (syntax-token 'b #:position 1 #:span 1))
(parser-derivation splice-label (parser-derivation splice-action
(parser-derivation (syntax-token 'c1 #:position 2 #:span 1)) (parser-derivation (syntax-token 'c1 #:position 2 #:span 1))
(parser-derivation (syntax-token 'c2 #:position 3 #:span 1)) (parser-derivation (syntax-token 'c2 #:position 3 #:span 1))
(parser-derivation (syntax-token 'c3 #:position 4 #:span 1))) (parser-derivation (syntax-token 'c3 #:position 4 #:span 1)))

24
base/grammar.rkt
Unescape Escape View File

@ -14,7 +14,7 @@
[cf-grammar-start-rules (-> cf-grammar? (set/c cf-production-rule? #:kind 'immutable))] [cf-grammar-start-rules (-> cf-grammar? (set/c cf-production-rule? #:kind 'immutable))]
[make-cf-grammar (-> #:rules (sequence/c cf-production-rule?) #:start-symbol any/c cf-grammar?)] [make-cf-grammar (-> #:rules (sequence/c cf-production-rule?) #:start-symbol any/c cf-grammar?)]
[make-cf-production-rule [make-cf-production-rule
(-> #:symbol any/c #:substitution (sequence/c grammar-symbol?) #:label derivation-label? (-> #:symbol any/c #:substitution (sequence/c grammar-symbol?) #:action semantic-action?
cf-production-rule?)])) cf-production-rule?)]))
@ -27,13 +27,14 @@
;@---------------------------------------------------------------------------------------------------- ;@----------------------------------------------------------------------------------------------------
;; Parsing takes a (Grammar T S L) and a sequence of (Token T V) and produces a set of ;; Parsing takes a (Grammar T S A) and a sequence of (Token T V) and produces a set of
;; (Parser-Derivation V L) (also called a "parse forest"). A grammar contains an immutable ;; (Parser-Derivation V A) (also called a "parse forest"). A grammar contains an immutable
;; vector of (Context-Free-Production-Rule T S L) and a start symbol of type S. ;; vector of (Context-Free-Production-Rule T S A) and a start symbol of type S.
;; T: the terminals the grammar parses. Corresponds to the type field of the input tokens. ;; T: the terminals the grammar parses. Corresponds to the type field of the input tokens.
;; S: the nonterminals the grammar rules are defined in terms of. ;; S: the nonterminals the grammar rules are defined in terms of.
;; L: the labels that grammar rules may have attached to them. These show up in parse tree ;; A: the labels that grammar rules may have attached to them via the (Label-Action A) semantic
;; branches, and can be used to determine which production rule produced a derivation. ;; action. These show up in parse tree branches, and can be used to determine which production
;; rule produced a derivation.
(struct cf-grammar (rules start-symbol) #:transparent) (struct cf-grammar (rules start-symbol) #:transparent)
@ -44,9 +45,10 @@
rule)) rule))
;; A (Context-Free-Production-Rule T S L) contains a nonterminal symbol of type S, a label of type L, ;; A (Context-Free-Production-Rule T S A) contains a nonterminal symbol of type S, semantic action of
;; and a substitution sequence of (Grammar-Symbol T S) values, stored in an immutable vector. ;; type (Semnatic-Action A), and a substitution sequence of (Grammar-Symbol T S) values, stored in an
(struct cf-production-rule (nonterminal label substitution) #:transparent) ;; immutable vector.
(struct cf-production-rule (nonterminal action substitution) #:transparent)
;; A (Grammar-Symbol T S) is either a (Terminal-Symbol T) or a (Nonterminal-Symbol S) ;; A (Grammar-Symbol T S) is either a (Terminal-Symbol T) or a (Nonterminal-Symbol S)
@ -62,5 +64,5 @@
(cf-grammar (sequence->vector rules) start)) (cf-grammar (sequence->vector rules) start))
(define (make-cf-production-rule #:symbol symbol #:substitution substitution #:label label) (define (make-cf-production-rule #:symbol symbol #:substitution substitution #:action action)
(cf-production-rule symbol label (sequence->vector substitution))) (cf-production-rule symbol action (sequence->vector substitution)))

40
parser/earley.rkt
Unescape Escape View File

@ -102,7 +102,7 @@
(guard (complete-sppf-key? key) then (guard (complete-sppf-key? key) then
(define tok (vector-ref tokens (complete-sppf-key-input-start key))) (define tok (vector-ref tokens (complete-sppf-key-input-start key)))
(stream (terminal-derivation (token-value tok)))) (stream (terminal-derivation (token-value tok))))
(define label (cf-production-rule-label (incomplete-sppf-key-rule key))) (define label (cf-production-rule-action (incomplete-sppf-key-rule key)))
(define possible-children (possible-children-lists forest key)) (define possible-children (possible-children-lists forest key))
(for*/stream ([children (in-stream possible-children)] (for*/stream ([children (in-stream possible-children)]
[processed-children (in-stream (cartesian-stream (map loop children)))]) [processed-children (in-stream (cartesian-stream (map loop children)))])
@ -261,26 +261,26 @@
(test-case "datum parser" (test-case "datum parser"
(define P-rule (define P-rule
(make-cf-production-rule (make-cf-production-rule
#:symbol 'P #:label (datum-label 'P) #:substitution (list (nonterminal-symbol 'S)))) #:symbol 'P #:action (label-action 'P) #:substitution (list (nonterminal-symbol 'S))))
(define S-rule0 (define S-rule0
(make-cf-production-rule (make-cf-production-rule
#:symbol 'S #:symbol 'S
#:label (datum-label 'S0) #:action (label-action 'S0)
#:substitution (list (nonterminal-symbol 'S) (terminal-symbol '+) (nonterminal-symbol 'M)))) #:substitution (list (nonterminal-symbol 'S) (terminal-symbol '+) (nonterminal-symbol 'M))))
(define S-rule1 (define S-rule1
(make-cf-production-rule (make-cf-production-rule
#:symbol 'S #:label (datum-label 'S1) #:substitution (list (nonterminal-symbol 'M)))) #:symbol 'S #:action (label-action 'S1) #:substitution (list (nonterminal-symbol 'M))))
(define M-rule0 (define M-rule0
(make-cf-production-rule (make-cf-production-rule
#:symbol 'M #:symbol 'M
#:label (datum-label 'M0) #:action (label-action 'M0)
#:substitution (list (nonterminal-symbol 'M) (terminal-symbol '*) (nonterminal-symbol 'T)))) #:substitution (list (nonterminal-symbol 'M) (terminal-symbol '*) (nonterminal-symbol 'T))))
(define M-rule1 (define M-rule1
(make-cf-production-rule (make-cf-production-rule
#:symbol 'M #:label (datum-label 'M1) #:substitution (list (nonterminal-symbol 'T)))) #:symbol 'M #:action (label-action 'M1) #:substitution (list (nonterminal-symbol 'T))))
(define T-rule (define T-rule
(make-cf-production-rule (make-cf-production-rule
#:symbol 'T #:label (datum-label 'T) #:substitution (list (terminal-symbol 'number)))) #:symbol 'T #:action (label-action 'T) #:substitution (list (terminal-symbol 'number))))
(define arithmetic-grammar (define arithmetic-grammar
(make-cf-grammar (make-cf-grammar
#:rules (list P-rule S-rule0 S-rule1 M-rule0 M-rule1 T-rule) #:start-symbol 'P)) #:rules (list P-rule S-rule0 S-rule1 M-rule0 M-rule1 T-rule) #:start-symbol 'P))
@ -290,51 +290,51 @@
(define parser (earley-parser arithmetic-grammar)) (define parser (earley-parser arithmetic-grammar))
(define expected-arithmetic-parse-tree (define expected-arithmetic-parse-tree
(parser-derivation (parser-derivation
(datum-label 'P) (label-action 'P)
(parser-derivation (parser-derivation
(datum-label 'S0) (label-action 'S0)
(parser-derivation (parser-derivation
(datum-label 'S1) (label-action 'S1)
(parser-derivation (parser-derivation
(datum-label 'M1) (parser-derivation (datum-label 'T) (parser-derivation 2)))) (label-action 'M1) (parser-derivation (label-action 'T) (parser-derivation 2))))
(parser-derivation 'plus) (parser-derivation 'plus)
(parser-derivation (parser-derivation
(datum-label 'M0) (label-action 'M0)
(parser-derivation (parser-derivation
(datum-label 'M1) (parser-derivation (datum-label 'T) (parser-derivation 3))) (label-action 'M1) (parser-derivation (label-action 'T) (parser-derivation 3)))
(parser-derivation 'times) (parser-derivation 'times)
(parser-derivation (datum-label 'T) (parser-derivation 4)))))) (parser-derivation (label-action 'T) (parser-derivation 4))))))
(check-equal? (parse-datum parser input-tokens) expected-arithmetic-parse-tree)) (check-equal? (parse-datum parser input-tokens) expected-arithmetic-parse-tree))
(test-case "syntax parser" (test-case "syntax parser"
(define P-rule (define P-rule
(make-cf-production-rule (make-cf-production-rule
#:symbol 'P #:label (syntax-label 'P) #:substitution (list (nonterminal-symbol 'S)))) #:symbol 'P #:action (label-action 'P) #:substitution (list (nonterminal-symbol 'S))))
(define S-rule0 (define S-rule0
(make-cf-production-rule (make-cf-production-rule
#:symbol 'S #:symbol 'S
#:label (syntax-label 'S0) #:action (label-action 'S0)
#:substitution (list (nonterminal-symbol 'S) (terminal-symbol '+) (nonterminal-symbol 'M)))) #:substitution (list (nonterminal-symbol 'S) (terminal-symbol '+) (nonterminal-symbol 'M))))
(define S-rule1 (define S-rule1
(make-cf-production-rule (make-cf-production-rule
#:symbol 'S #:label (syntax-label 'S1) #:substitution (list (nonterminal-symbol 'M)))) #:symbol 'S #:action (label-action 'S1) #:substitution (list (nonterminal-symbol 'M))))
(define M-rule0 (define M-rule0
(make-cf-production-rule (make-cf-production-rule
#:symbol 'M #:symbol 'M
#:label (syntax-label 'M0) #:action (label-action 'M0)
#:substitution (list (nonterminal-symbol 'M) (terminal-symbol '*) (nonterminal-symbol 'T)))) #:substitution (list (nonterminal-symbol 'M) (terminal-symbol '*) (nonterminal-symbol 'T))))
(define M-rule1 (define M-rule1
(make-cf-production-rule (make-cf-production-rule
#:symbol 'M #:label (syntax-label 'M1) #:substitution (list (nonterminal-symbol 'T)))) #:symbol 'M #:action (label-action 'M1) #:substitution (list (nonterminal-symbol 'T))))
(define T-rule (define T-rule
(make-cf-production-rule (make-cf-production-rule
#:symbol 'T #:label (syntax-label 'T) #:substitution (list (terminal-symbol 'number)))) #:symbol 'T #:action (label-action 'T) #:substitution (list (terminal-symbol 'number))))
(define arithmetic-grammar (define arithmetic-grammar
(make-cf-grammar (make-cf-grammar

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