Add cargo-machete prek hook

Cargo.toml

@@ -4,8 +4,6 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-fxhash = "0.2.1"
-num = "0.4.3"
 ppvm-pauli-sum = { version = "0.1.0", path = "crates/ppvm-pauli-sum" }
 ppvm-tableau = { version = "0.1.0", path = "crates/ppvm-tableau" }
 ppvm-sym = { version = "0.1.0", path = "crates/ppvm-sym" }

crates/ppvm-python-native/Cargo.toml

@@ -13,7 +13,6 @@ test = false
 
 [dependencies]
 bnum = "0.13.0"
-num = "0.4.3"
 paste = "1.0.15"
 ppvm-pauli-sum = { version = "0.1.0", path = "../ppvm-pauli-sum" }
 ppvm-stim = { version = "0.1.0", path = "../ppvm-stim", features = ["rayon"] }

crates/ppvm-tableau-sum/Cargo.toml

@@ -8,7 +8,6 @@ bitvec = "1.0.1"
 fxhash = "0.2.1"
 num = "0.4.3"
 ppvm-traits = { version = "0.1.0", path = "../ppvm-traits" }
-ppvm-pauli-word = { version = "0.1.0", path = "../ppvm-pauli-word" }
 ppvm-pauli-sum = { version = "0.1.0", path = "../ppvm-pauli-sum" }
 ppvm-tableau = { version = "0.1.0", path = "../ppvm-tableau" }
 rand = "0.10.1"

docs/src/pages/develop.astro

@@ -469,6 +469,18 @@ npm run build          # extract everything, then `astro build` → dist/</code>
         runners only start once Linux is fully green.
       </li>
     </ol>
+    <p>
+      <strong>Unused dependencies.</strong> A <code>cargo-machete</code>
+      <code>prek</code> hook flags unused crate dependencies across the whole
+      workspace (run from the repo root, <a href="https://github.com/bnjbvr/cargo-machete">cargo-machete</a>
+      recurses into every member). It is part of the hook suite, so it runs both
+      locally on commit and in CI via the <code>pre-commit</code> job — there is
+      no separate machete CI job. The binary is provisioned by <code>mise</code>
+      (<code>cargo:cargo-machete</code> in <code>mise.toml</code>), so the
+      mise-action step that sets up the other hooks installs it too. Silence a
+      false positive per-crate with
+      <code>[package.metadata.cargo-machete] ignored = [&hellip;]</code>.
+    </p>
     <p>
       <strong>Why cross-OS is extension-only.</strong> The compiled PyO3
       module is the only artifact whose build is OS-sensitive — macOS needs
@@ -616,6 +628,7 @@ chore: restore lockfile consistency</code></pre>
     <ul>
       <li>Run <code>cargo fmt --all</code> before committing Rust.</li>
       <li>Run <code>cargo clippy --workspace --all-targets</code>; fix or justify all warnings.</li>
+      <li>Run <code>cargo machete</code> to catch unused dependencies; it's also a <code>prek</code> hook, run on commit and in CI.</li>
       <li>Python is formatted with <code>ruff format</code> and linted with <code>ruff check</code>.</li>
       <li>Public Rust items should have doc comments; <code>cargo doc --no-deps</code> must build cleanly because the API site is built from rustdoc JSON.</li>
       <li>

mise.toml

@@ -2,3 +2,5 @@
 prek = "latest"
 # License header checker/formatter (used by prek hawkeye hook)
 "github:korandoru/hawkeye" = "latest"
+# Unused-dependency checker
+"cargo:cargo-machete" = "0.9.2"

ppvm-python/demo/hello_world.py

@@ -0,0 +1,32 @@
+"""Encode a message into a computational-basis state with GeneralizedTableau.
+
+Each bit of the ASCII encoding of "Hello, world!" gets one qubit. Starting
+from the all-zero state, we flip every qubit whose target bit is 1 with an X
+gate, then measure all qubits back out and decode them into the string.
+"""
+
+from ppvm import GeneralizedTableau
+
+MESSAGE = "Hello, world!"
+
+# ASCII bytes -> bit list, MSB first within each byte.
+data = MESSAGE.encode("ascii")
+bits = [(byte >> (7 - i)) & 1 for byte in data for i in range(8)]
+
+# One qubit per bit; flip every qubit whose target bit is 1.
+tab = GeneralizedTableau(n_qubits=len(bits))
+for q, bit in enumerate(bits):
+    if bit:
+        tab.x(q)
+
+# Measure all qubits and decode the outcomes back into a string.
+measured = [int(tab.measure(q)) for q in range(len(bits))]
+decoded = bytes(
+    int("".join(str(b) for b in measured[i : i + 8]), 2)
+    for i in range(0, len(measured), 8)
+).decode("ascii")
+
+print(f"qubits:  {len(bits)}")
+print(f"decoded: {decoded!r}")
+assert decoded == MESSAGE, f"round-trip failed: {decoded!r}"
+print("round-trip OK")

ppvm-python/demo/squin_kernel.py

@@ -0,0 +1,14 @@
+from ppvm import GeneralizedTableauSimulator
+from bloqade import squin
+
+@squin.kernel
+def main():
+    q = squin.qalloc(2)
+
+    squin.h(q[0])
+    squin.cnot(q[0], q[1])
+
+sim = GeneralizedTableauSimulator(2)
+task = sim.task(main)
+task.run()
+print(task.state)

prek.toml

@@ -47,6 +47,21 @@ entry = "cargo clippy --workspace -- -D warnings"
 pass_filenames = false
 types = ["rust"]
 
+# Rust: unused-dependency check across the whole workspace.
+# cargo-machete is installed via mise (see mise.toml); `mise exec --` is used so
+# the hook works even outside a mise-activated shell. This is the sole machete
+# check: it runs locally on commit and in CI via the `pre-commit` job (which
+# runs the full hook suite) — there is no separate cargo-machete CI job.
+[[repos]]
+repo = "local"
+[[repos.hooks]]
+id = "cargo-machete"
+name = "cargo machete (unused deps)"
+language = "system"
+entry = "mise exec -- cargo-machete"
+pass_filenames = false
+types = ["rust"]
+
 # Python: ruff format check
 [[repos]]
 repo = "local"