diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..85ac7e7
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,5 @@
+all:
+	@clang -g -lncurses -I include src/*.c main.c -o gen-flake
+
+bear:
+	@bear -- clang -g -lncurses -I include src/*.c main.c -o gen-flake
diff --git a/flake.nix b/flake.nix
index 27653ce..c281858 100644
--- a/flake.nix
+++ b/flake.nix
@@ -14,8 +14,7 @@
         pkgs = nixpkgs.legacyPackages.${system};
 
         codelldb = pkgs.writeShellScriptBin "codelldb" ''
-          #!/usr/bin/env bash
-          exec ${pkgs.vscode-extensions.vadimcn.vscode-lldb}/share/vscode/extensions/vadimcn.vscode-lldb/adapter/codelldb "$@"
+         exec ${pkgs.vscode-extensions.vadimcn.vscode-lldb}/share/vscode/extensions/vadimcn.vscode-lldb/adapter/codelldb "$@"
         '';
       in
       {
@@ -31,6 +30,9 @@
           buildInputs = with pkgs; [
             ncurses
           ];
+          shellHook = ''
+            export GEN_FLAKE_SPEC_PATH="${./specs}"
+          '';
         };
       }
     );
diff --git a/gen-flake b/gen-flake
new file mode 100755
index 0000000..11e4692
Binary files /dev/null and b/gen-flake differ
diff --git a/include/dyn_array.h b/include/dyn_array.h
new file mode 100644
index 0000000..e5770ee
--- /dev/null
+++ b/include/dyn_array.h
@@ -0,0 +1,16 @@
+#ifndef GEN_FLAKE_DYN_ARRAY_H
+#define GEN_FLAKE_DYN_ARRAY_H
+
+#include <stdlib.h>
+
+struct DynArray;
+
+struct DynArray *dyn_array_new(size_t capacity);
+
+size_t dyn_array_size(struct DynArray *a);
+
+void dyn_array_push(struct DynArray *a, void *item);
+
+void dyn_array_free(struct DynArray *a);
+
+#endif /* GEN_FLAKE_DYN_ARRAY_H */
diff --git a/main.c b/main.c
index 1f81122..697e4e0 100644
--- a/main.c
+++ b/main.c
@@ -1,7 +1,67 @@
-#include <stdlib.h>
+#include <assert.h>
 #include <curses.h>
+#include <glob.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "dyn_array.h"
+
+static int glob_specs(char *name, struct DynArray *entries) {
+  assert(name);
+  assert(entries);
+
+  int name_length = strlen(name);
+  char *pattern = malloc(name_length + 3);
+  if (!pattern) {
+    goto cleanup;
+  }
+  memcpy(pattern, name, name_length);
+  memcpy(pattern + name_length + 1, "/*", 3);
+
+  glob_t *pglob = 0;
+
+  int retval = 0;
+  if ((retval = glob(pattern, GLOB_ONLYDIR | GLOB_MARK, 0, pglob))) {
+    goto cleanup;
+  }
+
+  // GLOB_ONLYDIR is just a hint. We still need to actually verify the only
+  // results we are reading in are directories.
+  // TODO:
+
+  globfree(pglob);
+
+cleanup:
+  if (pattern) {
+    free(pattern);
+  }
+  return retval;
+}
+
+static void cleanup(int sig) {
+  endwin();
+
+  exit(EXIT_SUCCESS);
+}
 
 int main(int argc, char **argv) {
+  int num = 0;
 
-  return EXIT_SUCCESS;
+  if (argc != 2) {
+    fprintf(stderr, "Usage: gen-flake <spec>\n");
+    exit(EXIT_FAILURE);
+  }
+
+  // Allow interrupting the program cleanly.
+  // TODO: How does this cleanup spec correctly?
+  signal(SIGINT, cleanup);
+
+  initscr();
+  keypad(stdscr, TRUE); // Enable keyboard mapping.
+  nonl();               // Disables NL to CR/NL conversion on output.
+
+  cleanup(0);
 }
diff --git a/specs/clang/default/flake.nix b/specs/clang/default/flake.nix
new file mode 100644
index 0000000..0b6771f
--- /dev/null
+++ b/specs/clang/default/flake.nix
@@ -0,0 +1,36 @@
+{
+  description = ''
+  An opinionated clang flake.
+  '';
+
+  inputs = {
+    flake-utils.url = "github:numtide/flake-utils";
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+
+        codelldb = pkgs.writeShellScriptBin "codelldb" ''
+          #!/usr/bin/env bash
+          exec ${pkgs.vscode-extensions.vadimcn.vscode-lldb}/share/vscode/extensions/vadimcn.vscode-lldb/adapter/codelldb "$@"
+        '';
+      in
+      {
+        devShells.default = pkgs.mkShell.override {
+          # https://nixos.wiki/wiki/Using_Clang_instead_of_GCC
+          stdenv = pkgs.clangStdenv;
+        } {
+          packages = with pkgs; [
+            bear
+            clang-tools
+            codelldb
+          ];
+          buildInputs = with pkgs; [
+            ncurses
+          ];
+        };
+      });
+}
diff --git a/specs/clang/run.sh b/specs/clang/run.sh
new file mode 100644
index 0000000..fcdce00
--- /dev/null
+++ b/specs/clang/run.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+if [ -z "$VERSION" ]; then
+  VERSION="default"
+fi
+
+cp "$VERSION/flake.nix" "$OUT"
diff --git a/src/dyn_array.c b/src/dyn_array.c
new file mode 100644
index 0000000..38593ea
--- /dev/null
+++ b/src/dyn_array.c
@@ -0,0 +1,44 @@
+#include <assert.h>
+
+#include "dyn_array.h"
+
+struct DynArray {
+  void **buf;
+  // The size of @buf excluding `NUL`.
+  size_t size;
+  // The allocated size of @buf including `NUL`.
+  size_t _capacity;
+};
+
+struct DynArray *dyn_array_new(size_t capacity) {
+  struct DynArray *a = malloc(sizeof(struct DynArray));
+  a->buf = calloc(capacity, sizeof(void *));
+  a->size = 0;
+  a->_capacity = capacity;
+  return a;
+}
+
+size_t dyn_array_size(struct DynArray *a) {
+  assert(a);
+
+  return a->size;
+}
+
+void dyn_array_push(struct DynArray *a, void *item) {
+  assert(a);
+
+  if (a->size == a->_capacity) {
+    // We assume reallocation will work.
+    a->_capacity *= 2;
+    a = realloc(a, sizeof(void *) * a->_capacity);
+  }
+  a->size += 1;
+  a->buf[a->size] = item;
+}
+
+void dyn_array_free(struct DynArray *a) {
+  assert(a);
+
+  free(a->buf);
+  free(a);
+}