437 lines
17 KiB
Scheme
437 lines
17 KiB
Scheme
#lang mzscheme
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(require setup/main-collects
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scheme/local
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scheme/bool
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(only scheme/base
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build-string
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build-list
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build-vector
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compose)
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(rename scheme/base base-else else)
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"kw.ss")
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(require-for-syntax syntax/kerncase
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syntax/stx
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syntax/name
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setup/main-collects
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"private/stxset.ss")
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(provide boolean=? symbol=?
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identity
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compose
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true false
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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 identity (lambda (x) x))
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(define (loop-until 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-syntax (opt-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 "default value missing" stx (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 "bad identifier sequence" stx (syntax args))]))])
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(with-syntax ([clauses clauses])
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(syntax/loc stx
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(letrec ([name (case-lambda . clauses)]) name))))])))
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;; recur is another name for 'let' in a named let
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(define-syntax (recur stx)
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(syntax-case stx ()
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[(_ . rest) (syntax/loc stx (let . rest))]))
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;; define a recursive value
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;; implementation by Jens Axel Soegaard
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(define-syntax (rec stx)
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(syntax-case stx ()
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[(rec id expr)
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(identifier? #'id)
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#`(letrec ((id expr))
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#,(syntax-property #'id 'inferred-name (syntax-e #'id)))]
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[(rec (name id ...) body ...)
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(andmap identifier? (syntax->list #'(name id ...)))
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#`(letrec ((name (lambda (id ...) body ...)))
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#,(syntax-property #'name 'inferred-name (syntax-e #'name)))]
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[(rec (name id ... . did) body ...)
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(andmap identifier? (syntax->list #'(name did id ...)))
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#`(letrec ((name (lambda (id ... . did) body ...)))
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#,(syntax-property #'name 'inferred-name (syntax-e #'name)))]
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[_
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(raise-syntax-error
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#f "expects either an identifier followed by an expresion, or a (possibly dotted) sequence of identifiers followed by a body" stx)]))
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(define-syntax (evcase 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 (lambda (t)
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(syntax-case t (else base-else)
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[else (syntax #t)]
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[base-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)
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(car tests)))
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(raise-syntax-error
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#f "else is not in last clause" stx (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 [a-test (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 ...) (raise-syntax-error #f "invalid clause" stx s)]))
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(syntax->list (syntax (something ...))))]))
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(define-syntax (nor stx)
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(syntax-case stx ()
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[(_ expr ...) (syntax/loc stx (not (or expr ...)))]))
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(define-syntax (nand stx)
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(syntax-case stx ()
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[(_ expr ...) (syntax/loc stx (not (and expr ...)))]))
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(define-syntax (let+ 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 (format "illegal use of ~a for a clause" n) stx 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 _)
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(lambda (a b) (eq? (syntax-e b) (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 _)
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(lambda (a b) (eq? (syntax-e b) (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 ...)
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(map normal-var
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(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 ...)
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(map normal-var
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(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))
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ns-undefined)))
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(define (extract-module-directory stx)
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(let ([srcmod (let ([mpi (syntax-source-module stx)])
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(if (module-path-index? mpi)
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(module-path-index-resolve mpi)
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mpi))])
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(let ([name (resolved-module-path-name srcmod)])
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(and (path? name)
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(let-values ([(base name dir?) (split-path name)])
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(and (path? base)
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base))))))
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(define-syntax (this-expression-source-directory stx)
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(syntax-case stx ()
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[(_ sub)
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(let ([stx (syntax sub)])
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(let ([source-path
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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 (path->main-collects-relative
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(or (and source (file-exists? source)
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(let-values ([(base file dir?)
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(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? 'collects (car dir)))
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(with-syntax ([d dir])
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(syntax/loc stx (main-collects-relative->path 'd)))
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(with-syntax ([d (if (bytes? dir) dir (path->bytes dir))])
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(syntax/loc stx (bytes->path d)))))])
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(let ([mpi (syntax-source-module stx)])
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(if mpi
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(quasisyntax/loc stx
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(or (extract-module-directory (quote-syntax #,(datum->syntax-object
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stx
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'context
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stx
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stx)))
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#,source-path))
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source-path))))]
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[(_) #`(this-expression-source-directory #,stx)]))
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(define-syntax (this-expression-file-name stx)
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(syntax-case stx ()
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[(_ sub)
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(let ([stx #'sub])
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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-expression-file-name #,stx)]))
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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 #f "duplicate identifier" stx 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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[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 expr ctx kernel-forms def-ctx)])
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(syntax-case expr (begin define-syntaxes define-values)
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[(begin . rest)
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(loop (syntax->list #'rest))]
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[(define-syntaxes (id ...) rhs)
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(andmap identifier? (syntax->list #'(id ...)))
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(with-syntax ([rhs (local-transformer-expand
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#'rhs
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'expression
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null)])
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(syntax-local-bind-syntaxes
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(syntax->list #'(id ...))
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#'rhs def-ctx)
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(list #'(define-syntaxes (id ...) rhs)))]
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[(define-values (id ...) rhs)
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(andmap identifier? (syntax->list #'(id ...)))
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(let ([ids (syntax->list #'(id ...))])
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(syntax-local-bind-syntaxes ids #f def-ctx)
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(list expr))]
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[else
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(list expr)])))
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exprs)))])
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(internal-definition-context-seal def-ctx)
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(let loop ([exprs exprs]
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[prev-stx-defns null]
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[prev-defns null]
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[prev-exprs null])
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(cond
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[(null? exprs)
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#`(letrec-syntaxes+values
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#,(map stx-cdr (reverse prev-stx-defns))
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#,(map stx-cdr (reverse prev-defns))
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#,@(if (null? prev-exprs)
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(list #'(void))
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(reverse prev-exprs)))]
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[(and (stx-pair? (car exprs))
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(identifier? (stx-car (car exprs)))
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(module-identifier=? #'define-syntaxes (stx-car (car exprs))))
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(loop (cdr exprs)
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(cons (car exprs) prev-stx-defns)
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prev-defns
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prev-exprs)]
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[(and (stx-pair? (car exprs))
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(identifier? (stx-car (car exprs)))
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(module-identifier=? #'define-values (stx-car (car exprs))))
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(loop (cdr exprs)
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prev-stx-defns
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(cons (car exprs)
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(append
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(map (lambda (expr)
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#`(define-values () (begin #,expr (values))))
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prev-exprs)
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prev-defns))
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null)]
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[else (loop (cdr exprs)
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prev-stx-defns
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prev-defns
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(cons (car exprs) prev-exprs))]))))
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(define-syntax (begin-lifted stx)
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(syntax-case stx ()
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[(_ expr0 expr ...)
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(let ([name (syntax-local-name)])
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(if name
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(with-syntax ([name name])
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(syntax-local-lift-expression
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#'(let ([name (begin expr0 expr ...)])
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name)))
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(syntax-local-lift-expression
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#'(begin expr0 expr ...))))]))
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