diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2f7896d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+target/
diff --git a/LICENSE b/COPYING
similarity index 100%
rename from LICENSE
rename to COPYING
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..d57070b
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,288 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
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+ "cexpr",
+ "clang-sys",
+ "lazy_static",
+ "lazycell",
+ "log",
+ "peeking_take_while",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "rustc-hash",
+ "shlex",
+ "syn",
+ "which",
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+ "minimal-lexical",
+]
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+ "unicode-ident",
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+ "memchr",
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+ "regex-syntax",
+]
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+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
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+version = "0.1.0"
+dependencies = [
+ "toml",
+ "yacexits",
+]
+
+[[package]]
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+]
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+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
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+
+[[package]]
+name = "yacexits"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53fe740dd05c1bbc919431e842e6c1bea30195e0518ae99cae35b7f0730ddc18"
+dependencies = [
+ "bindgen",
+ "libc",
+]
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..3684870
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "tomcat"
+version = "0.1.0"
+edition = "2021"
+license = "AGPL-3.0-or-later"
+authors = [ "Emma Tebibyte <emma@tebibyte.media>" ]
+
+[dependencies]
+toml = "0.5.9"
+yacexits = "0.1.2"
diff --git a/README.md b/README.md
index 0e8f751..37199b7 100644
--- a/README.md
+++ b/README.md
@@ -1,10 +1,33 @@
-`tomcat` – a [TOML](https://toml.io) parser in POSIX shell
+`tomcat` – a minimal [TOML](https://toml.io) parser for the command line.
 
 ## Installation
 
 ### From Source
 
-Clone this repository and move the `tomcat` binary wherever your operating
-system stores locally-installed binaries. This is usually `/usr/local/bin` or
-`$HOME/.local/bin` for your user. Make sure the installation location is in your
-`$PATH`.
+1. Run `cargo --install --git https://git.tebibyte.media/emma/tomcat.git`
+2. ???
+3. Profit
+
+Also make sure that your cargo `bin` directory (by default in 
+`"$CARGO_HOME"/bin`) is in your `$PATH`; I recommend symlinking the folder to
+`"$HOME/.local/bin` and adding that to your user `$PATH`.
+
+## Usage
+
+Assuming the TOML file being parsed is `file.toml`:
+
+To get the value of top-level key `notable`:
+
+`tomcat notable file.toml`
+
+To get the value of `key` from the `main` table:
+
+`tomcat main.key file.toml`
+
+To get the value of `key` from the subtable `subtab` in table `main`:
+
+`tomcat main.subtab.key file.toml`
+
+To get the value of index `3` in array `arr` in table `main`:
+
+`tomcat main.arr[3] file.toml`
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..a5cee39
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,171 @@
+/* 
+ * Copyright (c) 2022–2023 Emma Tebibyte
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ */
+
+use std::{
+  env::args,
+  fs::File,
+  io::Read,
+  iter::Peekable,
+  os::fd::{ FromRawFd },
+  path::Path,
+  str::FromStr,
+};
+
+use toml::Value;
+use yacexits::*;
+
+fn parse_toml(
+  mut root: Value,
+  mut tabkey: Peekable<std::slice::Iter<'_, &str>>,
+  index: Option<usize>,
+) -> Result<String, (String, u32)> {
+  let mut out = String::new();
+
+  while let Some(item) = tabkey.next() {
+    let mut value = match root.get(item) {
+      Some(val) => val,
+      None => {
+        return Err((format!("{}: No such table or key.", item), EX_DATAERR));
+      },
+    };
+
+    match value {
+      Value::Array(array) => {
+        let i = match index {
+          Some(i) => i,
+          None => {
+            for v in array.iter() {
+              out.push_str(&format!("{}\n", v.to_string()));
+            }
+            continue;
+          },
+        };
+
+        match array.get(i) {
+          Some(val) => value = val,
+          None => {
+            return Err((format!("No value at index {}.", i), EX_DATAERR));
+          },
+        };
+      },
+      Value::Table(table) => {
+        if tabkey.peek().is_some() {
+          root = toml::Value::Table(table.to_owned());
+          continue;
+        };
+      },
+      _ => {
+        if tabkey.peek().is_some() {
+          return Err((format!("{}: Not a table.", item), EX_DATAERR));
+        }
+      },
+    };
+
+    match value {
+      Value::Array(_) => {},
+      Value::Boolean(boolean) => out.push_str(&format!("{:?}\n", boolean)), 
+      Value::Datetime(datetime) => out.push_str(&format!("{:?}\n", datetime)),
+      Value::Float(float) => out.push_str(&format!("{:?}\n", float)),
+      Value::Integer(int) => out.push_str(&format!("{:?}\n", int)),
+      Value::String(string) => {
+        let contents = string.to_owned();
+        let mut lines: Vec<&str> = contents.lines().collect();
+        if lines.last().unwrap().is_empty() { _ = lines.pop(); }
+
+        for line in lines.iter() { out.push_str(&format!("{}\n", line)); }
+      },
+      _ => return Err((format!("{:?}: No such key.", item), EX_DATAERR)),
+    };
+  }
+  Ok(out)
+}
+
+fn main() {
+  let argv: Vec<String> = args().collect();
+  let usage_info = format!("Usage: {} [table.]key[[index]] [file...]", argv[0]);
+
+  if argv.len() <= 1 {
+    eprintln!("{}", usage_info);
+    exit(EX_USAGE);
+  }
+
+  let input = argv.get(2).unwrap_or(&"".to_owned()).to_owned();
+
+  let mut content = Vec::new();
+  
+  match input.as_str() {
+    "-" | "" => unsafe { File::from_raw_fd(0) },
+    _ => {
+      File::open(Path::new(&input)).unwrap_or_else(|_| {
+        eprintln!(
+          "{}: {}: No such file or directory.",
+          argv[0],
+          &input
+        );
+        exit(EX_UNAVAILABLE);
+      })
+    },
+  }.read_to_end(&mut content).unwrap_or_else(|_| {
+      eprintln!("{}: Could not read input.", argv[0]);
+      exit(EX_OSERR);
+  });
+
+
+  let mut tabkey: Vec<&str> = argv[1].split(".").collect();
+  let mut indexvec = Vec::new();
+  let mut index: Option<usize> = None;
+
+  if tabkey.iter().skip(1).peekable().peek().is_some() {
+      indexvec = tabkey[1].split(&['[', ']'][..]).collect();
+      tabkey[1] = indexvec.remove(0);
+  };
+
+  if ! indexvec.is_empty() {
+    let istr = indexvec.remove(0);
+    match usize::from_str(istr) {
+      Ok(i) => index = Some(i),
+      Err(_) => {
+        eprintln!("{}: {}: Cannot index by given value.", argv[0], istr);
+        exit(EX_USAGE);
+      },
+    };
+  }
+
+  let root = String::from_utf8(content)
+    .unwrap_or_else(|_| {
+      eprintln!("{}: Input is not valid UTF-8.", argv[0]);
+      exit(EX_DATAERR);
+    })
+    .parse::<Value>()
+    .unwrap_or_else(|_| {
+      eprintln!("{}: Unable to parse TOML.", argv[0]);
+      exit(EX_DATAERR);
+    });
+
+  let valiter = tabkey.iter().peekable();
+  print!(
+    "{}",
+    match parse_toml(root, valiter, index) {
+      Ok(val) => val, 
+      Err((err, code)) => {
+        eprintln!("{}: {}", argv[0], err);
+        exit(code);
+      },
+    },
+  );
+}
diff --git a/tomcat b/tomcat
deleted file mode 100755
index f59bac2..0000000
--- a/tomcat
+++ /dev/null
@@ -1,73 +0,0 @@
-#!/bin/sh
-
-set -e
-
-argv0="$0"
-argv1="$1"
-argv2="$2"
-
-# check usage
-if ! test -n "$1"; then
-  printf "Usage: %s [OPTIONS] [TABLE.KEY[INDEX]] [FILE]\n" "$0" 1>&2
-  exit 64 # sysexits(3) EX_USAGE
-fi
-
-# test if input has a period
-if test -n "$(printf "%s\n" "$argv1" | sed -n '/.*\..*/p')"; then
-  # cut out everything beyond the first period for TABLE
-  TABLE=$(printf "%s\n" "$argv1" | sed -n 's/\..*//p')
-
-  # cut out everything before the first period for KEY
-  KEY=$(printf "%s\n" "$argv1" | sed -n 's/^[^.]*\.//p')
-  ! test -n "$KEY" &&\
-    printf "%s: No key specified\n" "$argv0" 1>&2 &&\
-    exit 65 # sysexits(3) EX_DATAERR
-else
-  printf "%s: No key specified\n" "$argv0" 1>&2
-  exit 65 # sysexits(3) EX_DATAERR
-fi
-
-# remove array index from KEY
-KEY=$(printf "%s\n" "$KEY" | sed 's/\[.*\]//g')
-# set ARR to the array index
-ARR=$(printf "%s\n" "$argv1" | sed -n 's/.\+\[//p' | tr -d ']')
-
-# test if argument 2 is a file or not
-if test -e "$argv2"; then
-  # set TOML to the text from the file
-  TOML=$(sed 's/[^"#]#\+.*//g' <"$argv2" | sed 's/^#.*//g' )
-else
-  # set TOML to the text from stdin
-  TOML=$(printf "%s\n" "$argv2" | sed 's/[^"#]#\+.*//g')
-fi
-
-if test -n "$TABLE"; then
-  KEYS=$(printf "%s\n" "$TOML" |\
-        # output only lines between TABLE and the next table
-          awk "/^\[$TABLE\]/{flag=1; next} /^\[/{flag=0} flag" - )
-else
-  KEYS=$(printf "%s\n" "$TOML" |\
-        # output only lines before the first table
-          awk '1;/^\[/{exit}' - | sed -n '/^[^[]/p')
-fi
-
-# set VAL to the parsed KEYS list
-VAL=$(printf "%s\n" "$KEYS" |\
-        # remove the key from the string and delineate arrays, removing
-        # brackets, trailing commas, and leading spaces
-        sed -n "s/$KEY *= *//p" | sed 's/", "/	/g' | tr -d '[]"' |\
-        sed 's/, *$//g' | sed 's/^ \+//g' | sed 's/ \+$//g')
-
-# test if ARR is set; if it is, then we have an array index to grab
-if test -n "$ARR"; then
-  # change the line delineator to newlines for parsing and output the result
-  printf "%s\n" "$VAL" | sed 's/	/\n/g' | head -n "$ARR" |\
-    tail -n 1
-elif !  test -n "$VAL"; then
-  printf "%s: %s: No such key or table\n" "$argv0" "$argv1" 1>&2
-  exit 65 # sysexits(3) EX_DATAERR
-else
-  printf "%s\n" "$VAL"
-fi
-
-exit 0