# V3 step 5.5 — library showcase (done 2026-09-22)

`tests/showcase11.mod` tours every standard library in one
separate-compilation session. Suite 95/95.

## Session

`showcase11.mod` + all six libraries
(`sysio`, `textio`, `wholeio`, `strings`, `math`, `files`) built
and linked into one image, run with stdin `42`.

## Output

```
Modula-2
8
42
12
42
```
Exit **80**. Verified by `expect_run_files_in`
(`Showcase11 → 80 [Modula-2]`, stdin `42`).

## What it exercises

- **Strings** — `Assign` ×2, `Concat` → `"Modula-2"`, `Length` → 8.
- **WholeIO** — `ReadCard` from stdin (42).
- **TextIO** — `WriteCard` echoes it.
- **Math** — `sqrt(144.0) + Pi - Pi` → 12.
- **Files** — `OpenWrite`, two `WriteChar`, `Close`, `OpenRead`,
  `ReadInt` → 42.
- **SysIO** — `Write` (string) + `WriteInt`/`WriteLn`.
- **Exit code** — `n - 12 + Length(u) + card` = `42-12+8+42` = 80.

## Constraint discovered while writing it

Because qualified access flattens names into the client scope, two
libraries exporting the same routine name (e.g. `TextIO.WriteInt`
and `Files.WriteInt`) cannot both be *used* in one scope — the
second resolves to the first. The showcase sidesteps this by using
each library's **distinct** names (the materialized set is
collision-free: `Write`/`WriteInt`/`WriteLn`/`WriteCard`/`ReadCard`/
`OpenWrite`/`WriteChar`/`Close`/`OpenRead`/`ReadInt`/`Assign`/
`Concat`/`Length`/`sqrt`/`Pi`). This is the concrete trigger for the
symbol-naming / real-qualified-resolution pass recorded in
`docs/session-2026-09-22-step5.md`; until then, callers must avoid
same-named imports from two modules.