603 lines
17 KiB
Scheme
603 lines
17 KiB
Scheme
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(module etc mzscheme
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(require "spidey.ss"
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(lib "plthome.ss" "setup"))
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(require-for-syntax (lib "kerncase.ss" "syntax")
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(lib "stx.ss" "syntax")
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(lib "name.ss" "syntax")
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(lib "context.ss" "syntax")
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(lib "plthome.ss" "setup")
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"list.ss"
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"private/stxset.ss")
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(provide true false
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boolean=? symbol=?
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identity
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compose
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build-string
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build-vector
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build-list
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loop-until
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opt-lambda
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local
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recur
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rec
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evcase
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nor
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nand
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let+
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namespace-defined?
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this-expression-source-directory
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this-expression-file-name
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define-syntax-set
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hash-table
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begin-with-definitions
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begin-lifted)
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(define true #t)
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(define false #f)
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(define identity (polymorphic (lambda (x) x)))
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(define compose
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(polymorphic
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(case-lambda
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[(f) (if (procedure? f) f (raise-type-error 'compose "procedure" f))]
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[(f g)
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(let ([f (compose f)]
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[g (compose g)])
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(if (eqv? 1 (procedure-arity f)) ; optimize: don't use call-w-values
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(if (eqv? 1 (procedure-arity g)) ; optimize: single arity everywhere
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(lambda (x) (f (g x)))
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(lambda args (f (apply g args))))
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(if (eqv? 1 (procedure-arity g)) ; optimize: single input
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(lambda (a)
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(call-with-values
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(lambda () (g a))
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f))
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(lambda args
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(call-with-values
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(lambda () (apply g args))
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f)))))]
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[(f . more)
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(let ([m (apply compose more)])
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(compose f m))])))
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(define build-string
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(lambda (n fcn)
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(unless (and (integer? n) (exact? n) (>= n 0))
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(error 'build-string "~s must be an exact integer >= 0" n))
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(unless (procedure? fcn)
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(error 'build-string "~s must be a procedure" fcn))
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(let ((str (make-string n)))
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(let loop ((i 0))
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(if (= i n)
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str
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(begin
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(string-set! str i (fcn i))
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(loop (add1 i))))))))
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;; (build-vector n f) returns a vector 0..n-1 where the ith element is (f i).
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;; The eval order is guaranteed to be: 0, 1, 2, ..., n-1.
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;; eg: (build-vector 4 (lambda (i) i)) ==> #4(0 1 2 3)
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(define build-vector
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(polymorphic
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(lambda (n fcn)
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(unless (and (integer? n) (exact? n) (>= n 0))
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(error 'build-vector "~s must be an exact integer >= 0" n))
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(unless (procedure? fcn)
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(error 'build-vector "~s must be a procedure" fcn))
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(let ((vec (make-vector n)))
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(let loop ((i 0))
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(if (= i n) vec
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(begin
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(vector-set! vec i (fcn i))
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(loop (add1 i)))))))))
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(define build-list
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(polymorphic
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(lambda (n fcn)
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(unless (and (integer? n) (exact? n) (>= n 0))
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(error 'build-list "~s must be an exact integer >= 0" n))
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(unless (procedure? fcn)
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(error 'build-list "~s must be a procedure" fcn))
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(if (zero? n) '()
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(let ([head (list (fcn 0))])
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(let loop ([i 1] [p head])
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(if (= i n) head
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(begin
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(set-cdr! p (list (fcn i)))
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(loop (add1 i) (cdr p))))))))))
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(define loop-until
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(polymorphic
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(lambda (start done? next body)
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(let loop ([i start])
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(unless (done? i)
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(body i)
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(loop (next i)))))))
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(define boolean=?
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(lambda (x y)
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(unless (and (boolean? x)
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(boolean? y))
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(raise-type-error 'boolean=?
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"boolean"
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(if (boolean? x) y x)))
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(eq? x y)))
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(define (symbol=? x y)
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(unless (and (symbol? x)
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(symbol? y))
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(raise-type-error 'symbol=? "symbol"
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(if (symbol? x) y x)))
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(eq? x y))
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(define-syntax opt-lambda
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(lambda (stx)
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(with-syntax ([name (or (syntax-local-infer-name stx)
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(quote-syntax opt-lambda-proc))])
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(syntax-case stx ()
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[(_ args body1 body ...)
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(let ([clauses (let loop ([pre-args null]
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[args (syntax args)]
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[needs-default? #f])
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(syntax-case args ()
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[id
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(identifier? (syntax id))
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(with-syntax ([(pre-arg ...) pre-args])
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(syntax ([(pre-arg ... . id)
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body1 body ...])))]
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[()
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(with-syntax ([(pre-arg ...) pre-args])
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(syntax ([(pre-arg ...)
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body1 body ...])))]
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[(id . rest)
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(identifier? (syntax id))
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(begin
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(when needs-default?
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(raise-syntax-error
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#f
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"default value missing"
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stx
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(syntax id)))
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(loop (append pre-args (list (syntax id)))
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(syntax rest)
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#f))]
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[([id default] . rest)
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(identifier? (syntax id))
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(with-syntax ([rest (loop (append pre-args (list (syntax id)))
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(syntax rest)
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#t)]
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[(pre-arg ...) pre-args])
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(syntax ([(pre-arg ...) (name pre-arg ... default)]
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. rest)))]
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[(bad . rest)
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(raise-syntax-error
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#f
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"not an identifier or identifier with default"
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stx
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(syntax bad))]
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[else
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(raise-syntax-error
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#f
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"bad identifier sequence"
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stx
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(syntax args))]))])
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(with-syntax ([clauses clauses])
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(syntax/loc stx
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(letrec ([name
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(case-lambda
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. clauses)])
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name))))]))))
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(define-syntax local
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(lambda (stx)
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(syntax-case stx ()
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[(_ (defn ...) body1 body ...)
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(let ([defs (let ([expand-context (generate-expand-context)])
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(let loop ([defns (syntax->list (syntax (defn ...)))])
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(apply
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append
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(map
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(lambda (defn)
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(let ([d (local-expand
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defn
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expand-context
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(kernel-form-identifier-list
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(quote-syntax here)))]
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[check-ids (lambda (ids)
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(for-each
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(lambda (id)
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(unless (identifier? id)
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(raise-syntax-error
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#f
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"not an identifier for definition"
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stx
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id)))
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ids))])
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(syntax-case d (define-values define-syntaxes begin)
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[(begin defn ...)
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(loop (syntax->list (syntax (defn ...))))]
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[(define-values (id ...) body)
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(begin
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(check-ids (syntax->list (syntax (id ...))))
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(list d))]
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[(define-values . rest)
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(raise-syntax-error
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#f
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"ill-formed definition"
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stx
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d)]
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[(define-syntaxes (id ...) body)
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(begin
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(check-ids (syntax->list (syntax (id ...))))
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(list d))]
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[(define-syntaxes . rest)
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(raise-syntax-error
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#f
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"ill-formed definition"
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stx
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d)]
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[_else
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(raise-syntax-error
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#f
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"not a definition"
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stx
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defn)])))
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defns))))])
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(let ([ids (apply append
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(map
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(lambda (d)
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(syntax-case d ()
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[(_ ids . __)
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(syntax->list (syntax ids))]))
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defs))])
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(let ([dup (check-duplicate-identifier ids)])
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(when dup
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(raise-syntax-error
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#f
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"duplicate identifier"
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stx
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dup)))
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(with-syntax ([(def ...) defs])
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(syntax/loc
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stx
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(let ()
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def ...
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(let ()
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body1
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body ...))))))]
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[(_ x body1 body ...)
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(raise-syntax-error
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#f
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"not a definition sequence"
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stx
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(syntax x))])))
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;; recur is another name for 'let' in a named let
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(define-syntax recur
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(lambda (stx)
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(syntax-case stx ()
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[(_ . rest)
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(syntax/loc stx (let . rest))])))
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;; define a recursive value
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(define-syntax rec
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(lambda (stx)
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(syntax-case stx ()
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[(_ name expr)
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(begin
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(unless (identifier? (syntax name))
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(raise-syntax-error
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#f
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"not an identifier"
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stx
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(syntax name)))
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(syntax/loc stx
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(letrec ([name expr])
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name)))])))
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(define-syntax evcase
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(lambda (stx)
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(syntax-case stx ()
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[(_ val [test body ...] ...)
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(let ([tests (syntax->list (syntax (test ...)))])
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(with-syntax ([(a-test ...)
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(map
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(lambda (t)
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(syntax-case t (else)
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[else (syntax #t)]
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[_else (with-syntax ([t t])
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(syntax (eqv? evcase-v t)))]))
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tests)])
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;; Make sure else is last:
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(unless (null? tests)
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(let loop ([tests tests])
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(unless (null? (cdr tests))
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(when (and (identifier? (car tests))
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(module-identifier=? (quote-syntax else) (car tests)))
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(raise-syntax-error
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#f
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"else is not in last clause"
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stx
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(car tests)))
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(loop (cdr tests)))))
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(syntax/loc stx
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(let ([evcase-v val])
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(cond
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[a-test
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(begin body ...)]
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...)))))]
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[(_ val something ...)
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;; Provide a good error message:
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(for-each
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(lambda (s)
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(syntax-case s ()
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[(t a ...)
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(raise-syntax-error
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#f
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"invalid clause"
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stx
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s)]))
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(syntax->list (syntax (something ...))))])))
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(define-syntax nor
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(lambda (stx)
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(syntax-case stx ()
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[(_ expr ...)
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(syntax/loc stx (not (or expr ...)))])))
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(define-syntax nand
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(lambda (stx)
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(syntax-case stx ()
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[(_ expr ...)
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(syntax/loc stx (not (and expr ...)))])))
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(define-syntax let+
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(lambda (stx)
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(syntax-case stx ()
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[(_ [clause ...] body1 body ...)
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(let ([clauses (syntax->list (syntax (clause ...)))]
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[bad (lambda (c n)
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(raise-syntax-error
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#f
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(format "illegal use of ~a for a clause" n)
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stx
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c))]
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[var? (lambda (x)
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(or (identifier? x)
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(let ([l (syntax->list x)])
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(and l
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(pair? l)
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(eq? (syntax-e (car l)) 'values)
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(andmap identifier? (cdr l))))))]
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[normal-var (lambda (x)
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(if (identifier? x)
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(list x)
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(cdr (syntax-e x))))])
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;; syntax checks
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(for-each
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(lambda (clause)
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(syntax-case* clause (val rec vals recs _) (lambda (a b)
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(eq? (syntax-e b)
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(syntax-e a)))
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[(val var expr)
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(var? (syntax var))
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'ok]
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[(rec var expr)
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(var? (syntax var))
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'ok]
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[(vals (var expr) ...)
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(andmap var? (syntax->list (syntax (var ...))))
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'ok]
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[(recs (var expr) ...)
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(andmap var? (syntax->list (syntax (var ...))))
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'ok]
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[(_ expr0 expr ...)
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'ok]
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[(val . __) (bad clause "val")]
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[(rec . __) (bad clause "rec")]
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[(vals . __) (bad clause "vals")]
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[(recs . __) (bad clause"recs")]
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[(_ . __) (bad clause "_")]
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[_else (raise-syntax-error #f "bad clause" stx clause)]))
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clauses)
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;; result
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(let loop ([clauses clauses])
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(if (null? clauses)
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(syntax (let () body1 body ...))
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(with-syntax ([rest (loop (cdr clauses))])
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(syntax-case* (car clauses) (val rec vals recs _) (lambda (a b)
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(eq? (syntax-e b)
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(syntax-e a)))
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[(val var expr)
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(with-syntax ([vars (normal-var (syntax var))])
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(syntax (let-values ([vars expr]) rest)))]
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[(rec var expr)
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(with-syntax ([vars (normal-var (syntax var))])
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(syntax (letrec-values ([vars expr]) rest)))]
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[(vals (var expr) ...)
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(with-syntax ([(vars ...) (map normal-var (syntax->list (syntax (var ...))))])
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(syntax (let-values ([vars expr] ...) rest)))]
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[(recs (var expr) ...)
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(with-syntax ([(vars ...) (map normal-var (syntax->list (syntax (var ...))))])
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(syntax (letrec-values ([vars expr] ...) rest)))]
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[(_ expr0 expr ...)
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(syntax (begin expr0 expr ... rest))])))))])))
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(define ns-undefined (gensym))
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(define (namespace-defined? n)
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(unless (symbol? n)
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(raise-type-error 'namespace-defined? "symbol" n))
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(not (eq? (namespace-variable-value n #t (lambda () ns-undefined)) ns-undefined)))
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(define-syntax (this-expression-source-directory stx)
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(syntax-case stx ()
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[(_)
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(let* ([source (syntax-source stx)]
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[source (and (path? source) source)]
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[local (or (current-load-relative-directory) (current-directory))]
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[dir (plthome-ify
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(or (and source (file-exists? source)
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(let-values ([(base file dir?) (split-path source)])
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(and (path? base)
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(path->complete-path base local))))
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local))])
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(if (and (pair? dir) (eq? 'plthome (car dir)))
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(with-syntax ([d dir])
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#'(un-plthome-ify 'd))
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(with-syntax ([d (if (bytes? dir) dir (path->bytes dir))])
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#'(bytes->path d))))]))
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(define-syntax (this-expression-file-name stx)
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(syntax-case stx ()
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[(_)
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(let* ([f (syntax-source stx)]
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[f (and f (path? f) (file-exists? f)
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(let-values ([(base file dir?) (split-path f)]) file))])
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(if f
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(with-syntax ([f (path->bytes f)]) #'(bytes->path f))
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#'#f))]))
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;; This is a macro-generating macro that wants to expand
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;; expressions used in the generated macro. So it's weird,
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;; and we put much of the work in a helper macro,
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;; `finish-syntax-set'.
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(define-syntax (define-syntax-set stx)
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(syntax-case stx ()
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[(_ (id ...) defn ...)
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(let ([ids (syntax->list (syntax (id ...)))])
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;; Check ids ------------------------------
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(for-each (lambda (id)
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(unless (identifier? id)
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(raise-syntax-error
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#f
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"not an identifier or two identifier in parentheses"
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stx
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id)))
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ids)
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(let ([dup (check-duplicate-identifier ids)])
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(when dup
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(raise-syntax-error
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#f
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"duplicate identifier"
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stx
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dup)))
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;; We'd like to check the `defns', but that requires
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;; and expansion in a different phase. So we move
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;; into that phase using `finish-syntax-set':
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(with-syntax ([orig-stx stx])
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(syntax/loc stx
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(define-syntaxes (id ...)
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(finish-syntax-set orig-stx)))))]))
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(define-syntax (hash-table stx)
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(syntax-case stx (quote)
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[(_ x ...)
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(let loop ([xs #'(x ...)] [flags '()])
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(syntax-case xs (quote)
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[('flag x ...) (loop #'(x ...) (cons #''flag flags))]
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[([key val] ...)
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(with-syntax ([(flag ...) (reverse flags)])
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(syntax/loc stx
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(let ([ht (make-hash-table flag ...)])
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(hash-table-put! ht key val) ...
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ht)))]
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[_else (raise-syntax-error 'hash-table "bad syntax" stx)]))]))
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(define-syntax (begin-with-definitions stx)
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;; Body can have mixed exprs and defns. Wrap expressions with
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;; `(define-values () ... (values))' as needed, and add a (void)
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;; at the end if needed.
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(let* ([def-ctx (syntax-local-make-definition-context)]
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[ctx (list (gensym 'intdef))]
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[kernel-forms (kernel-form-identifier-list
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(quote-syntax here))]
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[init-exprs (let ([v (syntax->list stx)])
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(unless v
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(raise-syntax-error #f "bad syntax" stx))
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(cdr v))]
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[exprs (let loop ([exprs init-exprs])
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(apply
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append
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(map (lambda (expr)
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(let ([expr (local-expand
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expr
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ctx
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kernel-forms
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|
def-ctx)])
|
|
(syntax-case expr (begin define-syntaxes define-values)
|
|
[(begin . rest)
|
|
(loop (syntax->list #'rest))]
|
|
[(define-syntaxes (id ...) rhs)
|
|
(andmap identifier? (syntax->list #'(id ...)))
|
|
(with-syntax ([rhs (local-transformer-expand
|
|
#'rhs
|
|
'expression
|
|
null)])
|
|
(syntax-local-bind-syntaxes (syntax->list #'(id ...)) #'rhs def-ctx)
|
|
(list #'(define-syntaxes (id ...) rhs)))]
|
|
[(define-values (id ...) rhs)
|
|
(andmap identifier? (syntax->list #'(id ...)))
|
|
(let ([ids (syntax->list #'(id ...))])
|
|
(syntax-local-bind-syntaxes ids #f def-ctx)
|
|
(list expr))]
|
|
[else
|
|
(list expr)])))
|
|
exprs)))])
|
|
(let loop ([exprs exprs][prev-stx-defns null][prev-defns null][prev-exprs null])
|
|
(cond
|
|
[(null? exprs)
|
|
#`(letrec-syntaxes+values
|
|
#,(map stx-cdr (reverse prev-stx-defns))
|
|
#,(map stx-cdr (reverse prev-defns))
|
|
#,@(if (null? prev-exprs)
|
|
(list #'(void))
|
|
(reverse prev-exprs)))]
|
|
[(and (stx-pair? (car exprs))
|
|
(identifier? (stx-car (car exprs)))
|
|
(module-identifier=? #'define-syntaxes (stx-car (car exprs))))
|
|
(loop (cdr exprs) (cons (car exprs) prev-stx-defns) prev-defns prev-exprs)]
|
|
[(and (stx-pair? (car exprs))
|
|
(identifier? (stx-car (car exprs)))
|
|
(module-identifier=? #'define-values (stx-car (car exprs))))
|
|
(loop (cdr exprs)
|
|
prev-stx-defns
|
|
(cons (car exprs)
|
|
(append
|
|
(map (lambda (expr)
|
|
#`(define-values () (begin #,expr (values))))
|
|
prev-exprs)
|
|
prev-defns))
|
|
null)]
|
|
[else
|
|
(loop (cdr exprs) prev-stx-defns prev-defns (cons (car exprs) prev-exprs))]))))
|
|
|
|
(define-syntax (begin-lifted stx)
|
|
(syntax-case stx ()
|
|
[(_ expr0 expr ...)
|
|
(let ([name (syntax-local-name)])
|
|
(if name
|
|
(with-syntax ([name name])
|
|
(syntax-local-lift-expression
|
|
#'(let ([name (begin expr0 expr ...)])
|
|
name)))
|
|
(syntax-local-lift-expression
|
|
#'(begin expr0 expr ...))))])))
|