russell@unturf.com
06b93c588a
Closes the last loop promised in the whitepaper's Future Work: a
node serves its state as an S-expression portal over HTTP, another
node pulls it down with tcp-connect + tcp-recv and materializes the
bindings locally via (eval (read-from-string line)).
examples/portal-http-server.lsp (90 lines):
- Holds some state (counter, my-int, my-list, my-fib, my-str)
- GET /portal → S-expression body: a sequence of (define ...) forms
- GET / → HTML index
- Uses heap-snapshot / heap-restore for O(1) memory on asm
examples/portal-http-client.lsp (90 lines):
- tcp-connect, send HTTP/1.0 GET, receive full response
- Strip headers (walk to first \r\n\r\n)
- Split body by \n, eval each non-empty, non-comment line
- The remote bindings are now live locally
3×3 server/client matrix: all 9 combinations green. Every runtime
hosts, every runtime consumes. The wire format is Scheme source;
no schema, no JSON, no Protobuf.
Prerequisite fix: `eval` semantics aligned across all three impls.
Python and C's `eval` special form previously evaluated its result
in the CALLER's env, so a nested (eval (read-from-string
"(define x 42)")) would install x in the local function scope —
invisible to later top-level code. asm's bi_eval always used the
global env (r14). With this commit, all three impls evaluate the
eval'd result in the global env, matching asm's existing behavior.
Python: uncommonlisp.py leval eval-handler now does `env = env.g`
before continuing the trampoline.
C: c/eval.c SYM_EVAL branch now does `env = env->global`.
asm: no change (already correct).
One pre-existing Python defect surfaced by the client:
`count` is a SRFI-1-style builtin (`d(S('count'), ...)`), so a
local let-loop variable named `count` collides with it in the
inline-cache lookup path and OP_LOOK_ADD1 fires on the builtin
instead of the local. Worked around by renaming the loop
accumulator to `cnt`. Underlying Env.lookup shortcut-to-global
issue is out of scope for this commit.
Regression: 975 tests still green.
99 lines
3.9 KiB
Text
99 lines
3.9 KiB
Text
;;; portal-http-client.lsp — fetch an S-expression portal over HTTP,
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;;; evaluate each form to materialize the bindings locally.
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;;;
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;;; This is the concrete demo of "portal over HTTP" from the whitepaper:
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;;; one machine serves its state, another pulls it down and resumes.
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;;; Because the portal format is Scheme source, the client is a few
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;;; lines of string-munging plus (read-from-string) + (eval).
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;;;
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;;; Usage (server must be running first — see portal-http-server.lsp):
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;;; python3 uncommonlisp.py --fast examples/portal-http-client.lsp
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;;; ./c/uncommonlisp examples/portal-http-client.lsp
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;;; ./asm/uncommonlisp < examples/portal-http-client.lsp
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(define *host* "127.0.0.1")
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(define *port* 9085)
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(define *request* "GET /portal HTTP/1.0\r\nHost: 127.0.0.1\r\nConnection: close\r\n\r\n")
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;;; ── Strip HTTP headers: body starts after the first "\r\n\r\n". ──
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;;; Portable implementation — walks bytes, tracks a 4-state matcher.
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(define (find-crlfcrlf s)
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(let ((len (string-length s)))
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(let loop ((i 0))
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(if (> (+ i 4) len)
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-1
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(if (and (= (char->integer (string-ref s i)) 13)
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(= (char->integer (string-ref s (+ i 1))) 10)
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(= (char->integer (string-ref s (+ i 2))) 13)
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(= (char->integer (string-ref s (+ i 3))) 10))
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(+ i 4)
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(loop (+ i 1)))))))
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(define (body-of resp)
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(let ((start (find-crlfcrlf resp)))
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(if (< start 0)
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""
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(substring resp start (string-length resp)))))
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;;; ── Fetch and evaluate ──────────────────────────────────────
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;;;
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;;; Read up to 64 KB of response in one tcp-recv. For a small
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;;; portal body this is always one packet on localhost.
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;;;
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;;; Then split the body by line, read+eval each non-empty,
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;;; non-comment line. Top-level define forms land in the global env.
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(define (first-n-chars s n)
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(if (> (string-length s) n) (substring s 0 n) s))
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(define (fetch-portal)
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(let ((sock (tcp-connect *host* *port*)))
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(if sock
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(begin
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(tcp-send sock *request*)
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(let ((resp (tcp-recv sock 65536)))
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(tcp-close sock)
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(body-of resp)))
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"")))
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(define (line-at s start)
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;; Extract line starting at index `start` (exclusive of \n).
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;; Returns the substring up to the next \n (or end).
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(let ((len (string-length s)))
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(let loop ((i start))
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(cond
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((= i len) (substring s start len))
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((= (char->integer (string-ref s i)) 10) (substring s start i))
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(else (loop (+ i 1)))))))
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(define (eval-all-lines s)
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(let ((len (string-length s)))
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(let loop ((i 0) (cnt 0))
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(if (>= i len) cnt
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(let ((line (line-at s i)))
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(let ((next (+ i (string-length line) 1)))
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(cond
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((= (string-length line) 0)
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(loop next cnt))
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((= (char->integer (string-ref line 0)) 59) ; ; = comment
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(loop next cnt))
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(else
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(eval (read-from-string line))
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(loop next (+ cnt 1))))))))))
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;;; ── Go ──────────────────────────────────────────────────────
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(define portal-body (fetch-portal))
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(display "fetched ") (display (string-length portal-body)) (display " bytes") (newline)
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(display "first line: ") (display (line-at portal-body 0)) (newline)
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(define evaluated (eval-all-lines portal-body))
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(display "evaluated ") (display evaluated) (display " forms") (newline)
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;; Now the remote bindings are live locally. Use them:
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(display "counter = ") (display counter) (newline)
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(display "my-int = ") (display my-int) (newline)
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(display "my-fib = ") (display my-fib) (newline)
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(display "my-list has ") (display (length my-list)) (display " items") (newline)
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(display "my-str = ") (display my-str) (newline)
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