# Showcase 14 — session capabilities end-to-end

Tags `v3-showcase14` (program) and `v3-showcase14-summary` (this doc).
Suite **127/127**; fixpoint **OK** (2,071,330 bytes).

## What it runs

`compiler/tests/showcase14.mod` (`Showcase14`) links seven modules and
exercises everything added this session:

```
IMPORT SysIO, TextIO, Utf8, Conversions, RealIO, ProgramArgs, IOChan;
```

1. **Enumerations** — `TYPE Color = (red, green, blue)`,
   `CONST Favourite = blue`; a literal as a `CASE` label, ordinal
   ordering (`red < green`), and a `CONST` initialiser.
2. **String content equality** — `"abc" = "abc"`, `"abc" # "abd"`.
3. **Unicode** — `Utf8.Decode("é", 0, cp, next)` (strict RFC 3629)
   back to `UCHAR`, checked with `UORD(cp) = 233`.
4. **Conversions** — `StrToInt("-56")` and `StrToReal("3.5")`
   round-trips; `IntToStr` used to render the result.
5. **ProgramArgs** — `ArgCount()` (run with no arguments).
6. **RealIO / TextIO** — `WriteReal(3.5)` and
   `UWriteString(U"ok ✓")` (UTF-8).
7. **IOChan** — `StdErrChan` diagnostics via the channel handle.

Each check adds to an accumulator; the program prints and exits with
it (42).

## Output

```
showcase14 n=42
3.500000E+00 ok ✓
```

(stdout; the `IOChan` line goes to stderr so that stdio buffering does
not reorder it against the unbuffered shim writes).

## Registration

`expect_run_files_out Showcase14 42 "showcase14 n=42" …` with the
`Utf8`/`SysShim`/`sysio`/`textio`/`conversions`/`realio`/`programargs`/
`iochan` definitions and bodies.

## Session features exercised

| Area | Where |
| --- | --- |
| Enums in expressions/CASE/CONST/params | `docs/summary_lang-polish.md` (`v3-lang-polish`) |
| String `=`/`#` | same |
| Unicode `UCHAR`/`UString`/`Utf8`/`TextIO.U*` | `docs/summary_unicode.md` (`v3-unicode-1/-2`) |
| `Conversions` / `RealIO` | `docs/summary_stdlib-conversions.md` |
| `ProgramArgs` / `IOChan` | `docs/summary_programargs-iochan.md` |

## Files

`compiler/tests/showcase14.mod`, `compiler/run_tests.sh`,
`docs/summary_showcase14.md`.