From fd7d8a412cd9d6c4cb8b4c2e43dabd65890267b8 Mon Sep 17 00:00:00 2001
From: Ryan Culpepper <ryanc@racket-lang.org>
Date: Mon, 3 Dec 2012 17:24:38 -0500
Subject: [PATCH] move lazy-require to racket/lazy-require

---
 collects/db/main.rkt                          |  2 +-
 collects/db/private/generic/dsn.rkt           |  2 +-
 collects/db/private/generic/place-server.rkt  |  2 +-
 collects/openssl/mzssl.rkt                    |  2 +-
 collects/plot/plot2d/plot.rkt                 |  2 +-
 collects/plot/plot3d/plot.rkt                 |  2 +-
 collects/racket/lazy-require.rkt              | 84 +++++++++++++++++++
 collects/racket/match/define-forms.rkt        |  2 +-
 collects/racket/match/match.rkt               |  2 +-
 collects/racket/place.rkt                     |  2 +-
 collects/scribblings/reference/syntax.scrbl   | 43 ++++++++++
 .../syntax/parse/experimental/reflect.rkt     |  2 +-
 .../syntax/parse/experimental/splicing.rkt    |  2 +-
 collects/syntax/parse/private/litconv.rkt     |  2 +-
 collects/syntax/parse/private/residual.rkt    |  2 +-
 collects/syntax/parse/private/sc.rkt          |  2 +-
 collects/typed-racket/base-env/prims.rkt      |  2 +-
 collects/typed-racket/env/global-env.rkt      |  2 +-
 collects/typed-racket/rep/free-variance.rkt   |  2 +-
 collects/typed-racket/rep/rep-utils.rkt       |  2 +-
 collects/typed-racket/rep/type-rep.rkt        |  2 +-
 collects/typed-racket/types/abbrev.rkt        |  2 +-
 collects/typed-racket/types/substitute.rkt    |  2 +-
 collects/typed-racket/types/subtype.rkt       |  2 +-
 collects/unstable/lazy-require.rkt            | 82 +-----------------
 .../unstable/scribblings/lazy-require.scrbl   | 36 --------
 26 files changed, 150 insertions(+), 139 deletions(-)
 create mode 100644 collects/racket/lazy-require.rkt

diff --git a/collects/db/main.rkt b/collects/db/main.rkt
index eaf701cd60..90a213c8dd 100644
--- a/collects/db/main.rkt
+++ b/collects/db/main.rkt
@@ -1,5 +1,5 @@
 #lang racket/base
-(require unstable/lazy-require
+(require racket/lazy-require
          racket/contract/base
          "base.rkt")
 (provide (all-from-out "base.rkt"))
diff --git a/collects/db/private/generic/dsn.rkt b/collects/db/private/generic/dsn.rkt
index 31eeb6d1c9..fcd36878f6 100644
--- a/collects/db/private/generic/dsn.rkt
+++ b/collects/db/private/generic/dsn.rkt
@@ -1,5 +1,5 @@
 #lang racket/base
-(require unstable/lazy-require
+(require racket/lazy-require
          syntax/parse/private/minimatch
          racket/file
          racket/list)
diff --git a/collects/db/private/generic/place-server.rkt b/collects/db/private/generic/place-server.rkt
index f27b2b0bc2..9219a9fab1 100644
--- a/collects/db/private/generic/place-server.rkt
+++ b/collects/db/private/generic/place-server.rkt
@@ -4,7 +4,7 @@
          syntax/parse/private/minimatch
          racket/place
          racket/serialize
-         unstable/lazy-require
+         racket/lazy-require
          "interfaces.rkt"
          "prepared.rkt")
 (provide connection-server)
diff --git a/collects/openssl/mzssl.rkt b/collects/openssl/mzssl.rkt
index 13e7cb5fda..1d62f8c2f8 100644
--- a/collects/openssl/mzssl.rkt
+++ b/collects/openssl/mzssl.rkt
@@ -33,7 +33,7 @@ TO DO:
          racket/port
          racket/tcp
          racket/string
-         unstable/lazy-require
+         racket/lazy-require
          "libcrypto.rkt"
          "libssl.rkt")
 (lazy-require
diff --git a/collects/plot/plot2d/plot.rkt b/collects/plot/plot2d/plot.rkt
index 3c5b490245..439cb7c745 100644
--- a/collects/plot/plot2d/plot.rkt
+++ b/collects/plot/plot2d/plot.rkt
@@ -6,7 +6,7 @@
          unstable/contract
          slideshow/pict
          unstable/parameter-group
-         unstable/lazy-require
+         racket/lazy-require
          unstable/latent-contract/defthing
          "../common/contract.rkt"
          "../common/math.rkt"
diff --git a/collects/plot/plot3d/plot.rkt b/collects/plot/plot3d/plot.rkt
index 43190ec3f6..d1818110df 100644
--- a/collects/plot/plot3d/plot.rkt
+++ b/collects/plot/plot3d/plot.rkt
@@ -6,7 +6,7 @@
          unstable/contract
          slideshow/pict
          unstable/parameter-group
-         unstable/lazy-require
+         racket/lazy-require
          unstable/latent-contract/defthing
          "../common/contract.rkt"
          "../common/math.rkt"
diff --git a/collects/racket/lazy-require.rkt b/collects/racket/lazy-require.rkt
new file mode 100644
index 0000000000..d74a2a645a
--- /dev/null
+++ b/collects/racket/lazy-require.rkt
@@ -0,0 +1,84 @@
+#lang racket/base
+(require (for-syntax racket/base)
+         compiler/cm-accomplice
+         racket/runtime-path
+         racket/promise)
+(provide lazy-require)
+
+(define-syntax (lazy-require stx)
+  (syntax-case stx ()
+    [(lazy-require #:requires-for-path (extra-req ...)
+                   [modpath (thing ...)] ...)
+     #`(begin
+         (lazy-require1 modpath (extra-req ...) (thing ...) #,stx)
+         ...)]
+    [(lazy-require [modpath (thing ...)] ...)
+     (syntax/loc stx
+       (lazy-require #:requires-for-path ()
+                     [modpath (thing ...)] ...))]))
+
+(define-for-syntax counter 0)
+
+(define-syntax (lazy-require1 stx)
+  (syntax-case stx ()
+    [(lazy-require1 modpath (extra-req ...) (name ...) orig-stx)
+     (with-syntax ([(defn ...)
+                    (for/list ([name (in-list (syntax->list #'(name ...)))])
+                      (unless (identifier? name)
+                        (raise-syntax-error #f "expected identifier" #'orig-stx name))
+                      (with-syntax ([name name]
+                                    [(aux) (generate-temporaries (list name))])
+                        #`(begin (define aux (make-lazy-function 'name get-sym))
+                                 (define-syntax name
+                                   (make-rename-transformer
+                                    (syntax-property (quote-syntax aux)
+                                                     'not-provide-all-defined #t))))))]
+                   [define-mpi-var
+                     (let ([phase (sub1 (variable-reference->phase (#%variable-reference)))])
+                       (if (zero? phase)
+                           ;; `define-runtime-module-path-index' works right at phase-level 0:
+                           #'(define-runtime-module-path-index mpi-var (quasiquote modpath))
+                           ;; need a submodule:
+                           (with-syntax ([lazy-require-path-n
+                                          (string->symbol
+                                           (format "lazy-require-path-~a-~a" 
+                                                   phase
+                                                   counter))])
+                             (set! counter (add1 counter))
+                             #'(begin
+                                 (module lazy-require-path-n racket/base
+                                   (require racket/runtime-path
+                                            (for-syntax racket/base)
+                                            extra-req ...)
+                                   (provide mpi-var)
+                                   (define-runtime-module-path-index mpi-var (quasiquote modpath)))
+                                 (require 'lazy-require-path-n)))))])
+       ;; implicit quasiquote, so can use normal module-path syntax
+       ;; or escape to compute a the module-path via expression
+       #'(begin 
+           define-mpi-var
+           (define (get-sym sym)
+             (parameterize ((current-namespace (variable-reference->namespace (#%variable-reference))))
+               (begin0
+                (dynamic-require mpi-var sym)
+                (do-registration (#%variable-reference) (quasiquote modpath)))))
+           defn ...))]))
+
+(define (make-lazy-function name get-sym)
+  ;; Use 'delay/sync' because 'delay' promise is not reentrant.
+  ;; FIXME: OTOH, 'delay/sync' promise is not kill-safe.
+  (let ([fun-p (delay/sync (get-sym name))])
+    (procedure-rename
+     (make-keyword-procedure
+      (lambda (kws kwargs . args)
+        (keyword-apply (force fun-p) kws kwargs args)))
+     name)))
+
+(define (do-registration vr modpath)
+  (let ([path (resolved-module-path-name
+               (module-path-index-resolve
+                (module-path-index-join
+                 modpath
+                 (variable-reference->resolved-module-path vr))))])
+    (when (path? path)
+      (register-external-module path))))
diff --git a/collects/racket/match/define-forms.rkt b/collects/racket/match/define-forms.rkt
index ba607f50b7..0546421802 100644
--- a/collects/racket/match/define-forms.rkt
+++ b/collects/racket/match/define-forms.rkt
@@ -6,7 +6,7 @@
                      unstable/sequence
                      syntax/parse
                      syntax/parse/experimental/template
-                     unstable/lazy-require))
+                     racket/lazy-require))
 
 (begin-for-syntax
  (lazy-require [racket/match/patterns (bound-vars)]
diff --git a/collects/racket/match/match.rkt b/collects/racket/match/match.rkt
index 93ced7d355..d547ece8a2 100644
--- a/collects/racket/match/match.rkt
+++ b/collects/racket/match/match.rkt
@@ -7,7 +7,7 @@
                   define-match-expander)
          "define-forms.rkt"
          "struct.rkt"
-         (for-syntax unstable/lazy-require
+         (for-syntax racket/lazy-require
                      (only-in "stxtime.rkt"
                               match-...-nesting
                               prop:match-expander
diff --git a/collects/racket/place.rkt b/collects/racket/place.rkt
index 81389c35d4..2d02af3eec 100644
--- a/collects/racket/place.rkt
+++ b/collects/racket/place.rkt
@@ -10,7 +10,7 @@
          racket/place/private/th-place
          racket/place/private/prop
          racket/private/streams
-         unstable/lazy-require
+         racket/lazy-require
 
 
          (for-syntax racket/base
diff --git a/collects/scribblings/reference/syntax.scrbl b/collects/scribblings/reference/syntax.scrbl
index 06e3917b23..a97b05bca7 100644
--- a/collects/scribblings/reference/syntax.scrbl
+++ b/collects/scribblings/reference/syntax.scrbl
@@ -13,6 +13,9 @@
                      racket/package
                      racket/splicing
                      racket/runtime-path
+                     racket/lazy-require
+                     (only-in compiler/cm-accomplice
+                              register-external-module)
                      racket/performance-hint))
 
 @(define require-eval (make-base-eval))
@@ -2777,3 +2780,43 @@ syntactic forms or languages that supply a more limited kind of
 Attaches a @racket['compiler-hint:cross-module-inline]
 @tech{syntax property} to each @racket[form], which is useful when a
 @racket[form] is a function definition. See @racket[define-values].}
+
+@;------------------------------------------------------------------------
+@section[#:tag "lazy-require"]{Importing Modules Lazily: @racket[lazy-require]}
+
+@note-lib-only[racket/lazy-require]
+
+@defform/subs[#:literals (unquote)
+              (lazy-require maybe-requires
+                            [mod (imported-fun-id ...)] ...)
+              ([mod module-path
+                    (unquote module-path-expr)]
+               [maybe-requires code:blank
+                               (code:line #:requires-for-path (require-spec ...))])
+              #:contracts ([module-path-expr module-path?])]{
+
+Defines each @racket[imported-fun-id] as a function that, when called,
+dynamically requires the export named @racket[imported-fun-id] from
+the module specified by @racket[mod] and calls it with the same
+arguments.
+
+The module @racket[mod] can be specified as a @racket[_module-path]
+(see @racket[require]) or as an @racket[unquote]-escaped expression
+that computes a module path. As with
+@racket[define-runtime-module-path-index], a @racket[module-path-expr]
+is evaluated both in phase level 0 and phase level 1 relative to its 
+enclosing phase level.
+
+If the enclosing relative phase level is not 0, then
+@racket[module-path-expr] is also placed in a submodule (with a use of
+@racket[define-runtime-module-path-index] at phase level 0 within the
+submodule); supply extra @racket[require-spec]s with
+@racket[#:requires-for-path] to bind within the submodule for
+@racket[module-path-expr]. Introduced submodules have the names
+@racket[lazy-require-]@racket[_n]@racketidfont{-}@racket[_m], where
+@racket[_n] is a phase-level number and @racket[_m] is a number.
+
+When the use of a lazily-required function triggers module loading,
+@racket[register-external-module] declares a potential compilation
+dependency (in case the function is used in the process of compiling a
+module).}
diff --git a/collects/syntax/parse/experimental/reflect.rkt b/collects/syntax/parse/experimental/reflect.rkt
index 809663f777..107438a902 100644
--- a/collects/syntax/parse/experimental/reflect.rkt
+++ b/collects/syntax/parse/experimental/reflect.rkt
@@ -1,6 +1,6 @@
 #lang racket/base
 (require (for-syntax racket/base
-                     unstable/lazy-require
+                     racket/lazy-require
                      syntax/parse/private/residual-ct) ;; keep abs.path
          racket/contract/base
          racket/contract/combinator
diff --git a/collects/syntax/parse/experimental/splicing.rkt b/collects/syntax/parse/experimental/splicing.rkt
index b6e026df95..de5f112a39 100644
--- a/collects/syntax/parse/experimental/splicing.rkt
+++ b/collects/syntax/parse/experimental/splicing.rkt
@@ -1,7 +1,7 @@
 #lang racket/base
 (require (for-syntax racket/base
                      syntax/parse
-                     unstable/lazy-require
+                     racket/lazy-require
                      "../private/kws.rkt")
          syntax/parse/private/residual) ;; keep abs. path
 (provide define-primitive-splicing-syntax-class)
diff --git a/collects/syntax/parse/private/litconv.rkt b/collects/syntax/parse/private/litconv.rkt
index 29e2b71600..1f5b901cad 100644
--- a/collects/syntax/parse/private/litconv.rkt
+++ b/collects/syntax/parse/private/litconv.rkt
@@ -1,6 +1,6 @@
 #lang racket/base
 (require (for-syntax racket/base
-                     unstable/lazy-require
+                     racket/lazy-require
                      "sc.rkt"
                      "lib.rkt"
                      "kws.rkt"
diff --git a/collects/syntax/parse/private/residual.rkt b/collects/syntax/parse/private/residual.rkt
index b9ef9bc0a3..10fcb522b6 100644
--- a/collects/syntax/parse/private/residual.rkt
+++ b/collects/syntax/parse/private/residual.rkt
@@ -1,7 +1,7 @@
 #lang racket/base
 (require (for-syntax racket/base)
          racket/stxparam
-         unstable/lazy-require)
+         racket/lazy-require)
 
 ;; ============================================================
 ;; Compile-time
diff --git a/collects/syntax/parse/private/sc.rkt b/collects/syntax/parse/private/sc.rkt
index 5cc902dac7..de6d2ddf18 100644
--- a/collects/syntax/parse/private/sc.rkt
+++ b/collects/syntax/parse/private/sc.rkt
@@ -1,6 +1,6 @@
 #lang racket/base
 (require (for-syntax racket/base
-                     unstable/lazy-require)
+                     racket/lazy-require)
          "keywords.rkt")
 
 ;; keep and keep as abs. path -- lazy-loaded macros produce references to this
diff --git a/collects/typed-racket/base-env/prims.rkt b/collects/typed-racket/base-env/prims.rkt
index d5e045fb79..1f15ee61c2 100644
--- a/collects/typed-racket/base-env/prims.rkt
+++ b/collects/typed-racket/base-env/prims.rkt
@@ -48,7 +48,7 @@ This file defines two sorts of primitives. All of them are provided into any mod
          "base-types-extra.rkt"
          racket/flonum ; for for/flvector and for*/flvector
          (for-syntax
-          unstable/lazy-require
+          racket/lazy-require
           syntax/parse
           racket/syntax
           racket/base
diff --git a/collects/typed-racket/env/global-env.rkt b/collects/typed-racket/env/global-env.rkt
index 314af04db2..b485b5af0a 100644
--- a/collects/typed-racket/env/global-env.rkt
+++ b/collects/typed-racket/env/global-env.rkt
@@ -5,7 +5,7 @@
 
 (require "../types/tc-error.rkt"
          syntax/id-table
-         unstable/lazy-require) 
+         racket/lazy-require) 
 (provide register-type register-type-if-undefined
          finish-register-type
          maybe-finish-register-type
diff --git a/collects/typed-racket/rep/free-variance.rkt b/collects/typed-racket/rep/free-variance.rkt
index 77e5e793a5..2e955d7524 100644
--- a/collects/typed-racket/rep/free-variance.rkt
+++ b/collects/typed-racket/rep/free-variance.rkt
@@ -3,7 +3,7 @@
          racket/match
          racket/set
          (for-syntax racket/base)
-         unstable/lazy-require
+         racket/lazy-require
          (contract-req)) 
 
 ;; Ugly hack - should use units
diff --git a/collects/typed-racket/rep/rep-utils.rkt b/collects/typed-racket/rep/rep-utils.rkt
index 604511df93..a0febd74b3 100644
--- a/collects/typed-racket/rep/rep-utils.rkt
+++ b/collects/typed-racket/rep/rep-utils.rkt
@@ -5,7 +5,7 @@
          (contract-req)
          "free-variance.rkt"
          "interning.rkt" unstable/struct
-         unstable/lazy-require
+         racket/lazy-require
          racket/stxparam
          (for-syntax
           racket/match
diff --git a/collects/typed-racket/rep/type-rep.rkt b/collects/typed-racket/rep/type-rep.rkt
index 7cae184855..bb2e429c7b 100644
--- a/collects/typed-racket/rep/type-rep.rkt
+++ b/collects/typed-racket/rep/type-rep.rkt
@@ -5,7 +5,7 @@
          "rep-utils.rkt" "object-rep.rkt" "filter-rep.rkt" "free-variance.rkt"
          racket/match ;mzlib/etc
          racket/contract
-         unstable/lazy-require
+         racket/lazy-require
          (for-syntax racket/base syntax/parse))
 
 ;; Ugly hack - should use units
diff --git a/collects/typed-racket/types/abbrev.rkt b/collects/typed-racket/types/abbrev.rkt
index 449fce6b39..8d858f4e15 100644
--- a/collects/typed-racket/types/abbrev.rkt
+++ b/collects/typed-racket/types/abbrev.rkt
@@ -14,7 +14,7 @@
          ;; avoid the other dependencies of `racket/place`
          '#%place
          unstable/function
-         unstable/lazy-require
+         racket/lazy-require
          (except-in racket/contract/base ->* -> one-of/c)
          (prefix-in c: racket/contract/base)
          (for-syntax racket/base syntax/parse racket/list)
diff --git a/collects/typed-racket/types/substitute.rkt b/collects/typed-racket/types/substitute.rkt
index 516ff918de..55f327e61d 100644
--- a/collects/typed-racket/types/substitute.rkt
+++ b/collects/typed-racket/types/substitute.rkt
@@ -8,7 +8,7 @@
          racket/match
          racket/set
          racket/contract
-         unstable/lazy-require)
+         racket/lazy-require)
 (lazy-require ("union.rkt" (Un)))
 
 (provide subst-all substitute substitute-dots substitute-dotted subst
diff --git a/collects/typed-racket/types/subtype.rkt b/collects/typed-racket/types/subtype.rkt
index c1fd35f24b..7a2fbe86ae 100644
--- a/collects/typed-racket/types/subtype.rkt
+++ b/collects/typed-racket/types/subtype.rkt
@@ -6,7 +6,7 @@
          (env type-name-env)
          racket/match unstable/match
          racket/function
-         unstable/lazy-require
+         racket/lazy-require
          (prefix-in c: racket/contract)
          (for-syntax racket/base syntax/parse))
 
diff --git a/collects/unstable/lazy-require.rkt b/collects/unstable/lazy-require.rkt
index ca62b95197..ada04ff02a 100644
--- a/collects/unstable/lazy-require.rkt
+++ b/collects/unstable/lazy-require.rkt
@@ -1,89 +1,9 @@
 #lang racket/base
 (require (for-syntax racket/base)
-         compiler/cm-accomplice
-         racket/runtime-path
-         racket/promise)
+         racket/lazy-require)
 (provide lazy-require
          begin-on-demand)
 
-(define-syntax (lazy-require stx)
-  (syntax-case stx ()
-    [(lazy-require #:requires-for-path (extra-req ...)
-                   [modpath (thing ...)] ...)
-     #`(begin
-         (lazy-require1 modpath (extra-req ...) (thing ...) #,stx)
-         ...)]
-    [(lazy-require [modpath (thing ...)] ...)
-     (syntax/loc stx
-       (lazy-require #:requires-for-path ()
-                     [modpath (thing ...)] ...))]))
-
-(define-for-syntax counter 0)
-
-(define-syntax (lazy-require1 stx)
-  (syntax-case stx ()
-    [(lazy-require1 modpath (extra-req ...) (name ...) orig-stx)
-     (with-syntax ([(defn ...)
-                    (for/list ([name (in-list (syntax->list #'(name ...)))])
-                      (unless (identifier? name)
-                        (raise-syntax-error #f "expected identifier" #'orig-stx name))
-                      (with-syntax ([name name]
-                                    [(aux) (generate-temporaries (list name))])
-                        #`(begin (define aux (make-lazy-function 'name get-sym))
-                                 (define-syntax name
-                                   (make-rename-transformer
-                                    (syntax-property (quote-syntax aux)
-                                                     'not-provide-all-defined #t))))))]
-                   [define-mpi-var
-                     (let ([phase (sub1 (variable-reference->phase (#%variable-reference)))])
-                       (if (zero? phase)
-                           ;; `define-runtime-module-path-index' works right at phase-level 0:
-                           #'(define-runtime-module-path-index mpi-var (quasiquote modpath))
-                           ;; need a submodule:
-                           (with-syntax ([lazy-require-path-n
-                                          (string->symbol
-                                           (format "lazy-require-path-~a-~a" 
-                                                   phase
-                                                   counter))])
-                             (set! counter (add1 counter))
-                             #'(begin
-                                 (module lazy-require-path-n racket/base
-                                   (require racket/runtime-path
-                                            (for-syntax racket/base)
-                                            extra-req ...)
-                                   (provide mpi-var)
-                                   (define-runtime-module-path-index mpi-var (quasiquote modpath)))
-                                 (require 'lazy-require-path-n)))))])
-       ;; implicit quasiquote, so can use normal module-path syntax
-       ;; or escape to compute a the module-path via expression
-       #'(begin 
-           define-mpi-var
-           (define (get-sym sym)
-             (parameterize ((current-namespace (variable-reference->namespace (#%variable-reference))))
-               (begin0
-                (dynamic-require mpi-var sym)
-                (do-registration (#%variable-reference) (quasiquote modpath)))))
-           defn ...))]))
-
-(define (make-lazy-function name get-sym)
-  ;; Use 'delay/sync' because 'delay' promise is not reentrant.
-  ;; FIXME: OTOH, 'delay/sync' promise is not kill-safe.
-  (let ([fun-p (delay/sync (get-sym name))])
-    (procedure-rename
-     (make-keyword-procedure
-      (lambda (kws kwargs . args)
-        (keyword-apply (force fun-p) kws kwargs args)))
-     name)))
-
-(define (do-registration vr modpath)
-  (let ([path (resolved-module-path-name
-               (module-path-index-resolve
-                (module-path-index-join
-                 modpath
-                 (variable-reference->resolved-module-path vr))))])
-    (when (path? path)
-      (register-external-module path))))
-
 #|
 begin-on-demand notes/todo
 
diff --git a/collects/unstable/scribblings/lazy-require.scrbl b/collects/unstable/scribblings/lazy-require.scrbl
index 358becb7ff..e48a912e03 100644
--- a/collects/unstable/scribblings/lazy-require.scrbl
+++ b/collects/unstable/scribblings/lazy-require.scrbl
@@ -11,42 +11,6 @@
 
 @defmodule[unstable/lazy-require]
 
-@defform/subs[#:literals (unquote)
-              (lazy-require maybe-requires
-                            [mod (imported-fun-id ...)] ...)
-              ([mod module-path
-                   (unquote module-path-expr)]
-               [maybe-requires code:blank
-                               (code:line #:requires-for-path (require-spec ...))])
-              #:contracts ([module-path-expr module-path?])]{
-
-Defines each @racket[imported-fun-id] as a function that, when called,
-dynamically requires the export named @racket['imported-fun-id] from
-the module specified by @racket[mod] and calls it with the same
-arguments.
-
-The module @racket[mod] can be specified as a @racket[_module-path]
-(see @racket[require]) or as an @racket[unquote]-escaped expression
-that computes a module path. As with
-@racket[define-runtime-module-path-index], a @racket[module-path-expr]
-is evaluated both in phase level 0 and phase level 1 relative to its 
-enclosing phase level.
-
-If the enclosing relative phase level is not 0, then
-@racket[module-path-expr] is also placed in a submodule (with a use of
-@racket[define-runtime-module-path-index] at phase level 0 within the
-submodule); supply extra @racket[require-spec]s with
-@racket[#:requires-for-path] to bind within the submodule for
-@racket[module-path-expr]. Introduced submodules have the names
-@racket[lazy-require-]@racket[_n]@racketidfont{-}@racket[_m], where
-@racket[_n] is a phase-level number and @racket[_m] is a number.
-
-When the use of a lazily-required function triggers module loading,
-@racket[register-external-module] declares a potential compilation
-dependency (in case the function is used in the process of compiling a
-module).}
-
-
 @defform[(begin-on-demand #:export (fun-id ...)
             body ...+)]{