(module ft-define "mzscheme-core.ss"
(require (rename #%kernel require-for-syntax require-for-syntax)
(rename #%kernel define-syntaxes define-syntaxes)
(rename #%kernel define-values define-values))
(require-for-syntax (all-except #%kernel #%module-begin lambda letrec) #%stxcase-scheme #%stx #%qqstx)
(provide define define-syntax define-for-syntax begin-for-syntax)
(define-syntaxes (define define-syntax define-for-syntax)
(let ([mk
(lambda (define-values-stx)
(lambda (stx)
(when (memq (syntax-local-context) '(expression))
(raise-syntax-error
#f
"not allowed in an expression context"
stx))
(syntax-case stx ()
[(_ id expr)
(identifier? #'id)
(quasisyntax/loc stx (#,define-values-stx (id) expr))]
[(_ id . rest)
(identifier? #'id)
(raise-syntax-error
#f
(syntax-case stx ()
[(_ id expr ...)
"bad syntax (multiple expressions after identifier)"]
[(_ id)
"bad syntax (zero expressions after identifier)"]
[(_ id . rest)
"bad syntax (illegal use of `.')"])
stx)]
[(_ something . rest)
(not (stx-pair? #'something))
(raise-syntax-error
#f
"bad syntax"
stx
#'something)]
[(_ proto . body)
(let-values ([(id mk-rhs)
(letrec ([simple-proto
(lambda (proto)
(let-values ([(args mk-rhs)
(syntax-case proto ()
[(id arg ...)
(values (syntax->list #'(arg ...))
(lambda (body)
(quasisyntax/loc stx (lambda (arg ...)
. #,body))))]
[(id arg ... . rest)
(values (syntax->list #'(arg ... rest))
(lambda (body)
(quasisyntax/loc stx
(lambda (arg ... . rest)
. #,body))))])])
(for-each (lambda (a)
(unless (identifier? a)
(raise-syntax-error
#f
"not an identifier for procedure argument"
stx
a)))
args)
(let ([dup (check-duplicate-identifier args)])
(when dup
(raise-syntax-error
#f
"duplicate argument identifier"
stx
dup)))
mk-rhs))]
[general-proto
(lambda (proto)
(syntax-case proto ()
[(id . rest)
(identifier? #'id)
(values #'id
(simple-proto proto))]
[((something . more) . rest)
(let-values ([(id mk-rhs) (general-proto #'(something . more))])
(let ([mk-inner (simple-proto proto)])
(values id
(lambda (body)
(mk-rhs (list (mk-inner body)))))))]
[(other . rest)
(raise-syntax-error
#f
"bad syntax (not an identifier for procedure name, and not a nested procedure form)"
stx
#'other)]))])
(general-proto #'proto))])
(unless (stx-list? #'body)
(raise-syntax-error
#f
"bad syntax (illegal use of `.' for procedure body)"
stx))
(when (stx-null? #'body)
(raise-syntax-error
#f
"bad syntax (no expressions for procedure body)"
stx))
(quasisyntax/loc stx (#,define-values-stx (#,id) #,(mk-rhs #'body))))])))])
(values (mk #'define-values)
(mk #'define-syntaxes)
(mk #'define-values-for-syntax))))
(define-syntaxes (begin-for-syntax)
(lambda (stx)
(let ([ctx (syntax-local-context)])
(unless (memq ctx '(module module-begin top-level))
(raise-syntax-error #f "allowed only at the top-level or a module top-level" stx))
(syntax-case stx ()
[(_) #'(begin)]
[(_ elem)
(not (eq? ctx 'module-begin))
(let ([e (local-transformer-expand/capture-lifts
#'elem
ctx
(syntax->list
#'(begin
define-values
define-syntaxes
define-values-for-syntax
set!
let-values
let*-values
letrec-values
lambda
case-lambda
if
quote
letrec-syntaxes+values
fluid-let-syntax
with-continuation-mark
#%app
#%top
#%datum)))])
(syntax-case* e (begin define-values define-syntaxes require require-for-template)
module-transformer-identifier=?
[(begin v ...)
#'(begin-for-syntax v ...)]
[(define-values (id ...) expr)
#'(define-values-for-syntax (id ...) expr)]
[(require v ...)
#'(require-for-syntax v ...)]
[(require-for-template v ...)
#'(require v ...)]
[(define-syntaxes (id ...) expr)
(raise-syntax-error
#f
"syntax definitions not allowed within begin-for-syntax"
#'elem)]
[other
#'(define-values-for-syntax () (begin other (values)))]))]
[(_ elem ...)
(syntax/loc stx (begin (begin-for-syntax elem) ...))])))))