+/*
+ * Normalised `An' splitting argument.
+ */
+enum mdoc_auth {
+ AUTH__NONE = 0,
+ AUTH_split,
+ AUTH_nosplit
+};
+
+/*
+ * Normalised `Bf' font type.
+ */
+enum mdoc_font {
+ FONT__NONE = 0,
+ FONT_Em,
+ FONT_Li,
+ FONT_Sy
+};
+
+/*
+ * Normalised arguments for `Bd'.
+ */
+struct mdoc_bd {
+ const char *offs; /* -offset */
+ enum mdoc_disp type; /* -ragged, etc. */
+ int comp; /* -compact */
+};
+
+/*
+ * Normalised arguments for `Bl'.
+ */
+struct mdoc_bl {
+ const char *width; /* -width */
+ const char *offs; /* -offset */
+ enum mdoc_list type; /* -tag, -enum, etc. */
+ int comp; /* -compact */
+ size_t ncols; /* -column arg count */
+ const char **cols; /* -column val ptr */
+};
+
+/*
+ * Normalised arguments for `Bf'.
+ */
+struct mdoc_bf {
+ enum mdoc_font font; /* font */
+};
+
+/*
+ * Normalised arguments for `An'.
+ */
+struct mdoc_an {
+ enum mdoc_auth auth; /* -split, etc. */
+};
+
+/*
+ * Consists of normalised node arguments. These should be used instead
+ * of iterating through the mdoc_arg pointers of a node: defaults are
+ * provided, etc.
+ */
+union mdoc_data {
+ struct mdoc_an An;
+ struct mdoc_bd *Bd;
+ struct mdoc_bf *Bf;
+ struct mdoc_bl *Bl;
+};
+
+/*
+ * Single node in tree-linked AST.
+ */