# Recovered 2024 Tcl source patches (G-096)

Origin: `c:/buildtcl/2024zig/build_tcl90/patch/` (reference snapshot
`TEMP_REFERENCE/2024zig/build_tcl90/patch/`), written against ~Tcl 9.0b4-era sources
(Aug 2024; tclZipfs/tclCmdIL Nov 2024). Recovered into tracked form 2026-07-20 - these
files previously existed only in those two VCS-ignored on-disk copies.

The tclZipfs/tclCmdIL patches are NOT applied by any build. The piperepl capability
IS built by default since 2026-07-20 - as SEPARATE products (`tclsh90spr`,
`tclsh90sprzip`) compiled from the rebased `tclMain_piperepl_905.c`; the stock
`tclsh90s`/`tclsh90szip` products continue to compile upstream sources unpatched.
NAMING NOTE: the spr names are suite-internal WORKING names - the published family
naming (G-103) will carry 'punk' in patched runtime names (e.g tclsh905punk.exe,
user 2026-07-21) so patched and unpatched are never confusable.

## tclMain.c.piperepl.patch / tclMain_piperepl.c  (the TCLSH_PIPEREPL capability)

`tclMain_piperepl.c` is the full patched file; the `.patch` is its diff against the
era's stock `tclMain.c`.

Purpose (the G-096 goal capability): allow returning to a standard C-level tcl repl
after launching from a kit with its own `main.tcl` - not possible with unmodified
sources. Gated by the `TCLSH_PIPEREPL` env var (unset/`0` = stock behaviour). When
enabled:

- Publishes `::tclsh(istty)` (unlinked fact) plus linked `::tclsh(dorepl)` and
  `::tclsh(evalinput)` before the startup script runs; a script-arg launch defaults
  `dorepl` to 0 (stock semantics) but the script may set `::tclsh(dorepl) 1` to drop
  into the interactive repl after it completes.
- Piped (non-tty) input the script did not consume is accumulated into
  `::tclsh(inputbuffer)` rather than evaluated as commands, unless the script opts in
  with `::tclsh(evalinput) 1` - protects arbitrary piped data from accidental eval.
- On stdin eof with `dorepl` set, stdin is reopened from the console (`CONIN$` on
  windows, `/dev/tty` elsewhere) and installed as the std channel, yielding a live
  standard repl after a pipeline ends.

Status: REBASED 2026-07-20 as `tclMain_piperepl_905.c` (stock 9.0.5 tclMain.c + this
patch, which applied cleanly at offset 4, + the gate-default flip). GATE SEMANTICS
CHANGED from the 2024 original per the G-103 punk-kit policy: the patched binary is
ENABLED unless `TCLSH_PIPEREPL=0` (2024 was opt-in via set-and-not-"0"). Even
enabled it is inert for scripts that never set `::tclsh(dorepl)` - script-arg runs
default dorepl to 0, and unconsumed piped input is buffered rather than eval'd. The
stock-behaviour escape hatches are `TCLSH_PIPEREPL=0` and the unpatched plain
products. Era files (`tclMain_piperepl.c`, the `.patch`) are kept unmodified as the
recovered 2024 artifacts. Known divergence when the gate is OPEN: `tcl_interactive`
is linked to the internal tty flag BEFORE the startup script runs (stock links it
only when entering the repl loop). Two visible effects: a script that WRITES
::tcl_interactive influences prompting behaviour in the patched shell where stock
would ignore the write until repl entry (load-bearing - it is how a piped script
that sets dorepl opts into prompts/echo in the reopened repl); and a script-arg
launch from a CONSOLE READS 1 where stock reads 0 (stock sets it once to
`!path && istty`; the early link overwrites that with the tty flag. Piped launches
read 0 either way, so only console script runs diverge for readers - verified
against punk9_beta 2026-07-23). Patch rev 2026-07-24 (G-118 items 1+7; in-source, effective at the next suite
rebuild - the G-117 cycle): the "? reopen stdin from console" notice is emitted
only when TCLSH_PIPEREPL_DEBUG is set truthy (stock prints nothing entering a
repl), and the reopen-path messages (gated notice + genuine failure messages)
moved from stdout to STDERR; ::tclsh(reopened) is published as an unlinked fact
(0 at gate-open startup, republished 1 after a successful console reopen) -
previously inferable only via `info exists ::tclsh(inputbuffer)`. Note the
punkshell-level analogue for the punk repl is G-038 (piped-to-interactive session
continuity) - this patch is the plain-tclsh/kit-runtime counterpart.

## tclZipfs.patch, tclCmdIL.patch

Companion experiment patches from the same era (zipfs behaviour and tclCmdIL tweak),
recovered for durability; unexamined in detail. See the fossil-era notes in
`TEMP_REFERENCE/2024zig/build_tcl90/patch/` (doc/, prev/, test_zipfs_patch/) for their
surrounding experiment context.