(begin ;; There are two ways to name a library: (foo bar) or foo.bar ;; The former is normalized to the latter. (define (mangle name) (when (null? name) (error "library name should be a list of at least one symbols" name)) (define (->string n) (cond ((symbol? n) (let ((str (symbol->string n))) (string-for-each (lambda (c) (when (or (char=? c #\.) (char=? c #\:)) (error "elements of library name may not contain '.' or ':'" n))) str) str)) ((and (number? n) (exact? n) (<= 0 n)) (number->string n)) (else (error "symbol or non-negative integer is required" n)))) (define (join strs delim) (let loop ((res (car strs)) (strs (cdr strs))) (if (null? strs) res (loop (string-append res delim (car strs)) (cdr strs))))) (if (symbol? name) name ; TODO: check symbol names (string->symbol (join (map ->string name) ".")))) (define current-library (make-parameter '(picrin base) mangle)) (define *libraries* (make-dictionary)) (define (find-library name) (dictionary-has? *libraries* (mangle name))) (define (make-library name) (let ((name (mangle name))) (let ((env (make-environment (string->symbol (string-append (symbol->string name) ":")))) (exports (make-dictionary))) ;; set up initial environment (set-identifier! 'define-library 'define-library env) (set-identifier! 'import 'import env) (set-identifier! 'export 'export env) (set-identifier! 'cond-expand 'cond-expand env) (dictionary-set! *libraries* name `(,env . ,exports))))) (define (library-environment name) (car (dictionary-ref *libraries* (mangle name)))) (define (library-exports name) (cdr (dictionary-ref *libraries* (mangle name)))) (define (library-import name sym alias) (let ((uid (dictionary-ref (library-exports name) sym))) (let ((env (library-environment (current-library)))) (set-identifier! alias uid env)))) (define (library-export sym alias) (let ((env (library-environment (current-library))) (exports (library-exports (current-library)))) (dictionary-set! exports alias (find-identifier sym env)))) ;; R7RS library syntax (let ((define-transformer (lambda (name macro) (add-macro! name macro)))) (define-transformer 'define-library (lambda (form _) (let ((name (cadr form)) (body (cddr form))) (or (find-library name) (make-library name)) (parameterize ((current-library name)) (for-each (lambda (expr) (eval expr name)) ; TODO parse library declarations body))))) (define-transformer 'cond-expand (lambda (form _) (letrec ((test (lambda (form) (or (eq? form 'else) (and (symbol? form) (memq form (features))) (and (pair? form) (case (car form) ((library) (find-library (cadr form))) ((not) (not (test (cadr form)))) ((and) (let loop ((form (cdr form))) (or (null? form) (and (test (car form)) (loop (cdr form)))))) ((or) (let loop ((form (cdr form))) (and (pair? form) (or (test (car form)) (loop (cdr form)))))) (else #f))))))) (let loop ((clauses (cdr form))) (if (null? clauses) #undefined (if (test (caar clauses)) `(,(make-identifier 'begin default-environment) ,@(cdar clauses)) (loop (cdr clauses)))))))) (define-transformer 'import (lambda (form _) (let ((caddr (lambda (x) (car (cdr (cdr x))))) (prefix (lambda (prefix symbol) (string->symbol (string-append (symbol->string prefix) (symbol->string symbol))))) (getlib (lambda (name) (if (find-library name) name (error "library not found" name))))) (letrec ((extract (lambda (spec) (case (car spec) ((only rename prefix except) (extract (cadr spec))) (else (getlib spec))))) (collect (lambda (spec) (case (car spec) ((only) (let ((alist (collect (cadr spec)))) (map (lambda (var) (assq var alist)) (cddr spec)))) ((rename) (let ((alist (collect (cadr spec))) (renames (map (lambda (x) `(,(car x) . ,(cadr x))) (cddr spec)))) (map (lambda (s) (or (assq (car s) renames) s)) alist))) ((prefix) (let ((alist (collect (cadr spec)))) (map (lambda (s) (cons (prefix (caddr spec) (car s)) (cdr s))) alist))) ((except) (let ((alist (collect (cadr spec)))) (let loop ((alist alist)) (if (null? alist) '() (if (memq (caar alist) (cddr spec)) (loop (cdr alist)) (cons (car alist) (loop (cdr alist)))))))) (else (dictionary-map (lambda (x) (cons x x)) (library-exports (getlib spec)))))))) (letrec ((import (lambda (spec) (let ((lib (extract spec)) (alist (collect spec))) (for-each (lambda (slot) (library-import lib (cdr slot) (car slot))) alist))))) (for-each import (cdr form))))))) (define-transformer 'export (lambda (form _) (letrec ((collect (lambda (spec) (cond ((symbol? spec) `(,spec . ,spec)) ((and (list? spec) (= (length spec) 3) (eq? (car spec) 'rename)) `(,(list-ref spec 1) . ,(list-ref spec 2))) (else (error "malformed export"))))) (export (lambda (spec) (let ((slot (collect spec))) (library-export (car slot) (cdr slot)))))) (for-each export (cdr form)))))) ;; bootstrap... (let () (make-library '(picrin base)) (set-car! (dictionary-ref *libraries* (mangle '(picrin base))) default-environment) (let ((export-keywords (lambda (keywords) (let ((env (library-environment '(picrin base))) (exports (library-exports '(picrin base)))) (for-each (lambda (keyword) (dictionary-set! exports keyword keyword)) keywords))))) (export-keywords '(define lambda quote set! if begin define-macro let let* letrec letrec* let-values let*-values define-values quasiquote unquote unquote-splicing and or cond case else => do when unless parameterize define-syntax syntax-quote syntax-unquote syntax-quasiquote syntax-unquote-splicing let-syntax letrec-syntax syntax-error)) (export-keywords '(features eq? eqv? equal? not boolean? boolean=? pair? cons car cdr null? set-car! set-cdr! caar cadr cdar cddr list? make-list list length append reverse list-tail list-ref list-set! list-copy map for-each memq memv member assq assv assoc current-input-port current-output-port current-error-port port? input-port? output-port? port-open? close-port eof-object? eof-object read-u8 peek-u8 read-bytevector! write-u8 write-bytevector flush-output-port open-input-bytevector open-output-bytevector get-output-bytevector number? exact? inexact? inexact exact = < > <= >= + - * / number->string string->number procedure? apply symbol? symbol=? symbol->string string->symbol make-identifier identifier? identifier=? identifier-base identifier-environment vector? vector make-vector vector-length vector-ref vector-set! vector-copy! vector-copy vector-append vector-fill! vector-map vector-for-each list->vector vector->list string->vector vector->string bytevector? bytevector make-bytevector bytevector-length bytevector-u8-ref bytevector-u8-set! bytevector-copy! bytevector-copy bytevector-append bytevector->list list->bytevector call-with-current-continuation call/cc values call-with-values char? char->integer integer->char char=? char? char<=? char>=? current-exception-handlers with-exception-handler raise raise-continuable error error-object? error-object-message error-object-irritants error-object-type string? string make-string string-length string-ref string-set! string-copy string-copy! string-fill! string-append string-map string-for-each list->string string->list string=? string? string<=? string>=? make-parameter with-dynamic-environment read make-dictionary dictionary? dictionary dictionary-has? dictionary-ref dictionary-set! dictionary-delete! dictionary-size dictionary-map dictionary-for-each dictionary->alist alist->dictionary dictionary->plist plist->dictionary make-record record? record-type record-datum default-environment make-environment find-identifier set-identifier! eval compile add-macro! make-ephemeron-table write write-simple write-shared display)) (export-keywords '(find-library make-library current-library))) (set! eval (let ((e eval)) (lambda (expr . lib) (let ((lib (if (null? lib) (current-library) (car lib)))) (e expr (library-environment lib)))))) (make-library '(picrin user)) (current-library '(picrin user))))