diff --git a/src/main.py b/src/main.py
new file mode 100644
index 0000000..b331883
--- /dev/null
+++ b/src/main.py
@@ -0,0 +1,144 @@
+import yaml
+import argparse
+import re
+import json
+from pathlib import Path
+
+parser = argparse.ArgumentParser(description="Process some integers.")
+parser.add_argument("file", type=Path, help="yaml config")
+parser.add_argument("--json", action="store_true", help="output as json")
+parser.add_argument("--out", type=Path, help="write into file")
+
+args = parser.parse_args()
+
+
+# ╔───────────────────────────────────────────────────────────────────────────╗
+# │ Λssεrτiδηs                                                                |
+# ╚───────────────────────────────────────────────────────────────────────────╝
+def check_for_duplicates(host, props):
+    seen = set()
+
+    for v in props:
+        if v in seen:
+            raise SyntaxError(f"Duplicate key on `{host}`: `{v}`")
+        else:
+            seen.add(v)
+
+
+def check_duplicate_hosts(data):
+    hosts = set()
+
+    for host in data:
+        if host in hosts:
+            raise SyntaxError(f"Duplicate host: `{host}`")
+        hosts.add(host)
+
+
+def run_assertions(host, props):
+    check_for_duplicates(host, props)
+
+
+# ╔───────────────────────────────────────────────────────────────────────────╗
+# │ Pαrsεr                                                                    |
+# ╚───────────────────────────────────────────────────────────────────────────╝
+def expand_for_loop(props):
+    expand = list()
+
+    for loop in props.get("for", []):
+        r = loop["range"]
+
+        if isinstance(r, dict):
+            start = int(r["from"])
+            cease = int(r["to"])
+            inc = int(r.get("increment", 1))
+
+            iterations = range(start, cease, inc)
+        elif isinstance(r, list):
+            iterations = r
+        else:
+            raise TypeError("Expected list or dict in `for` loop `range`")
+
+        pattern = re.compile(rf'\$\{{{loop["variable"]}\}}')
+
+        for i in iterations:
+            expand.append(pattern.sub(str(i), loop["template"]))
+
+    return expand
+
+
+def get_ssh_props(data):
+    props = list()
+
+    for k, v in data["ssh_props"].items():
+        if isinstance(v, list):
+            for x in v:
+                props.append(f"{k} {x}")
+        else:
+            props.append(f"{k} {v}")
+
+    return props
+
+
+def stringify_booleans(props):
+    pattern = re.compile(r"(True|False)$")
+
+    def replace_bools(s):
+        m = pattern.search(s)
+
+        if m and m[1] == "True":
+            return pattern.sub("true", s)
+        elif m and m[1] == "False":
+            return pattern.sub("false", s)
+        else:
+            return s
+
+    return [replace_bools(prop) for prop in props]
+
+
+def parse_yaml(data):
+    expanded = dict()
+    check_duplicate_hosts(data)
+
+    for host, props in data.items():
+        parsed = list()
+        parsed.extend(get_ssh_props(props))
+        parsed.extend(expand_for_loop(props))
+
+        parsed = stringify_booleans(parsed)
+        run_assertions(host, parsed)
+
+        expanded[host] = sorted(parsed)
+
+    return expanded
+
+
+# ╔───────────────────────────────────────────────────────────────────────────╗
+# │ Fδrmαττεr                                                                 |
+# ╚───────────────────────────────────────────────────────────────────────────╝
+def to_ssh_config_string(parse):
+    s = str()
+
+    for host, keys in parse.items():
+        s += f"Host {host}\n"
+        for key in keys:
+            s += f"\t{key}\n"
+        s += "\n"
+
+    return s
+
+
+# ╔───────────────────────────────────────────────────────────────────────────╗
+# │ Mαiη                                                                      |
+# ╚───────────────────────────────────────────────────────────────────────────╝
+with open(args.file, "r") as f:
+    data = yaml.safe_load(f)
+
+parse = parse_yaml(data)
+
+if args.json:
+    print(json.dumps(parse))
+elif args.out:
+    with open(args.out, 'w') as f:
+        f.write(to_ssh_config_string(parse))
+else:
+    print(to_ssh_config_string(parse), end="")