Alexander Medvednikov
0355826d9f
* driver: forward termination signals to run children * cgen: embed run signal helpers in portable snapshots * driver: terminate inherited run child handlers before exec * driver: preserve signal dispositions and pending termination * driver: isolate run signal delivery while preserving job control * driver: relay terminal interrupts to output pipeline peers * driver: relay caught terminal stops and clean failed run groups * cache: track all embedded native helper inputs
44 lines
2.2 KiB
Markdown
44 lines
2.2 KiB
Markdown
# Running inline V code
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Use `v -e 'println(1)'` or `v -e='println(1)'` to compile and run a short V script.
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Imports and top-level statements work just as they do in a `.vsh` file.
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Compiler options go before `-e`. Arguments after the code are passed to the program,
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including compiler command names and flags such as `version`, `doc`, and `--help`:
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```sh
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v -prod -e 'import os; println(os.args[1..])' first 'with spaces'
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```
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The command returns the program's exit status. A temporary source file in the current
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working directory and the implicit executable are removed when the compilation or program
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finishes, including when interrupted with `Ctrl-C` or `Ctrl-\`.
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On Unix, the program runs in a separate process group. Handled signals sent to V's
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group are forwarded once. V forwards `SIGTERM`, `SIGHUP`, `SIGINT`, and `SIGQUIT` and waits for the
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program before removing temporary files. After `SIGTERM` or `SIGHUP`, V exits with
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`128 + signal`. Signals inherited as ignored remain ignored, including `SIGHUP` under `nohup`.
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Interactive programs receive the foreground terminal while running. Terminal input and
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shell job control (`Ctrl-Z`, `fg`, and `bg`) continue to work. Terminal interrupts also reach
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peers in an output pipeline, even if the program handles the interrupt and keeps running.
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Terminal `Ctrl-Z` also suspends the original pipeline when the program catches or ignores
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`SIGTSTP`. Failed signal setup terminates the verified program group, including its descendants.
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Catchable job-control stop signals
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sent to V are forwarded to the program. Uncatchable `SIGKILL` and `SIGSTOP` sent only to V
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cannot be forwarded to the separate program group. With piped or redirected stdin, the
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original job keeps the foreground terminal so pipeline peers can read it. A program that
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opens `/dev/tty` directly in this configuration runs in a background group and may stop
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when accessing that terminal.
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Use `v -http` to serve the current directory on `localhost:4001`. This is equivalent to:
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```sh
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v -e 'import net.http.file; file.serve()'
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```
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For another directory or port, pass `file.serve` options in the inline source:
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```sh
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v -e 'import net.http.file; file.serve(folder: "/tmp", on: ":5002")'
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```
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