<div dir="ltr">Not entirely, no.  For example,  syntax-case and other macro systems can't be layered over syntax-rules.  


By the same token,


the Posix API (SRFI 170) can't be layered over R7RS-small.  It could be layered over an FFI, but there are just too many different kinds of FFIs out there.  

<div><br></div><div>Here's the current list of non-portable SRFIs and pre-SRFIs that I have proposed to be voted on:</div><div><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Conditions: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/ConditionsCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">ConditionsCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">File I/O: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/FilesAdvancedCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">FilesAdvancedCowan</a> plus <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/SettingsListsCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SettingsListsCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Threads: <a href="http://srfi.schemers.org/srfi-18/srfi-18.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 18</a> plus optional <a href="http://srfi.schemers.org/srfi-21/srfi-21.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 21</a> or <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/FuturesCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">FuturesCowan</a> (simplified with monad)</p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Sockets: <a href="http://srfi.schemers.org/srfi-106/srfi-106.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 106</a> or <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/NetworkPortsCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">NetworkPortsCowan</a> with <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/NetworkEndpointsCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">NetworkEndpointsCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Datagram channels (UDP sockets): <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/DatagramChannelsCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">DatagramChannelsCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Timers: <a href="http://srfi.schemers.org/srfi-120/srfi-120.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 120</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Mutable environments: <a href="https://htmlpreview.github.io/?https://bitbucket.org/cowan/r7rs-wg1-infra/raw/default/EnvironmentsMIT.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">EnvironmentsMIT</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Host environment (Posix): <a href="https://htmlpreview.github.io/?https://bitbucket.org/cowan/r7rs-wg1-infra/raw/default/srfi-170.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 170</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Access to the REPL: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/ReplCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">ReplCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Library declarations: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/LibraryDeclarationsCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">LibraryDeclarationsCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Interfaces: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/InterfacesCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">InterfacesCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Process control: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/ProcessesCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">ProcessesCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">System commands: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/SystemCommandCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SystemCommandCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Pure delay/force: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/PureDelayedGloria.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">PureDelayedGloria</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Delimited continuations: <a href="https://docs.racket-lang.org/reference/cont.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">Racket</a>, <a href="https://www.gnu.org/software/guile/manual/html_node/Prompt-Primitives.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">Guile</a>, <a href="https://github.com/tonyg/kali-scheme/blob/master/scheme/misc/shift-reset.scm" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">Scheme48/Kali</a>, <a href="https://practical-scheme.net/gauche/man/gauche-refe/Partial-continuations.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">Gauche</a>, <a href="http://wiki.call-cc.org/eggref/4/F-operator" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">Chicken</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Continuation marks: <a href="http://srfi.schemers.org/srfi-157/srfi-157.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 157</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Extended exact numbers: <a href="http://srfi.schemers.org/srfi-73/srfi-73.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 73</a> or <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/ExtendedRationalsCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">ExtendedRationalsCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Adjustable strings: <a href="http://srfi.schemers.org/srfi-118/srfi-118.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 118</a> (basic) or <a href="http://srfi.schemers.org/srfi-140/srfi-140.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 140</a> (mutable/immutable)</p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Mutexes, condition variables: <a href="http://srfi.schemers.org/srfi-18/srfi-18.html" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">SRFI 18</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Port type detector: see ticket <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/issues/177/distinguish-file-and-string-ports" rel="nofollow" title="Distinguish file and string ports?" class="gmail-ap-connect-link" style="color:rgb(0,82,204);text-decoration-line:none"><s>#177</s></a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Internationalization of strings: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/GettextCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">GettextCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Chronometers: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/Chronometer.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">Chronometer</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Character-cell terminals: <a href="https://bitbucket.org/cowan/r7rs-wg1-infra/src/4a3907a8b871518b0cf81e08084da6850278175b/TerminalsCowan.md" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">TerminalsCowan</a></p><p style="margin:12px 0px 0px;padding:0px;color:rgb(23,43,77);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,"Fira Sans","Droid Sans","Helvetica Neue",sans-serif;font-size:14px">Graphics canvas: <a href="http://smallbasic.com/doc/?id=8&language=" rel="nofollow" style="color:rgb(0,82,204);text-decoration-line:none">CanvasCowan</a></p></div><div><br><div>Comments are extremely welcome.</div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Dec 21, 2019 at 7:24 PM Hendrik Boom <<a href="mailto:hendrik@topoi.pooq.com">hendrik@topoi.pooq.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Sat, Dec 21, 2019 at 11:02:55PM +0200, Lassi Kortela wrote:<br>
> <br>
> R6RS is quite a big language and there are already so many good<br>
> implementations of it that new ones might not have much to add. Same<br>
> situation as with Common Lisp. R7RS is such a small language that all kinds<br>
> of niche implementations are interesting and useful to explore.<br>
<br>
Which is why they split R7RS into a small language and a large language that<br>
I home can be implemented entirely on top of the small langauge.<br>
<br>
-- hendrik<br>
<br>
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