expr: Tell expressions what kind of expression they are

src/color.c

@@ -1136,14 +1136,20 @@ static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose, i
 		return -1;
 	}
 
-	if (bfs_expr_is_parent(expr)) {
-		if (cbuff(cfile, "${red}%pq${rs}", expr->argv[0]) < 0) {
-			return -1;
-		}
-	} else {
-		if (cbuff(cfile, "${blu}%pq${rs}", expr->argv[0]) < 0) {
-			return -1;
-		}
+	int ret;
+	switch (expr->kind) {
+	case BFS_FLAG:
+		ret = cbuff(cfile, "${cyn}%pq${rs}", expr->argv[0]);
+		break;
+	case BFS_OPERATOR:
+		ret = cbuff(cfile, "${red}%pq${rs}", expr->argv[0]);
+		break;
+	default:
+		ret = cbuff(cfile, "${blu}%pq${rs}", expr->argv[0]);
+		break;
+	}
+	if (ret < 0) {
+		return -1;
 	}
 
 	for (size_t i = 1; i < expr->argc; ++i) {

src/expr.c

@@ -12,7 +12,9 @@
 #include "xregex.h"
 #include <string.h>
 
-struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval_fn, size_t argc, char **argv) {
+struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval_fn, size_t argc, char **argv, enum bfs_kind kind) {
+	bfs_assert(kind != BFS_PATH);
+
 	struct bfs_expr *expr = arena_alloc(&ctx->expr_arena);
 	if (!expr) {
 		return NULL;
@@ -22,6 +24,7 @@ struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval_fn, size_t
 	expr->eval_fn = eval_fn;
 	expr->argc = argc;
 	expr->argv = argv;
+	expr->kind = kind;
 	expr->probability = 0.5;
 	SLIST_PREPEND(&ctx->expr_list, expr, freelist);
 

src/expr.h

@@ -15,6 +15,27 @@
 #include <sys/types.h>
 #include <time.h>
 
+/**
+ * Argument/token/expression kinds.
+ */
+enum bfs_kind {
+	/** A flag (-H, -L, etc.). */
+	BFS_FLAG,
+
+	/** A root path. */
+	BFS_PATH,
+
+	/** An option (-follow, -mindepth, etc.). */
+	BFS_OPTION,
+	/** A test (-name, -size, etc.). */
+	BFS_TEST,
+	/** An action (-print, -exec, etc.). */
+	BFS_ACTION,
+
+	/** An operator (-and, -or, etc.). */
+	BFS_OPERATOR,
+};
+
 /**
  * Integer comparison modes.
  */
@@ -97,6 +118,8 @@ struct bfs_expr {
 	size_t argc;
 	/** The command line arguments comprising this expression. */
 	char **argv;
+	/** The kind of expression this is. */
+	enum bfs_kind kind;
 
 	/** The number of files this expression keeps open between evaluations. */
 	int persistent_fds;
@@ -207,7 +230,7 @@ struct bfs_ctx;
 /**
  * Create a new expression.
  */
-struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval, size_t argc, char **argv);
+struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval, size_t argc, char **argv, enum bfs_kind kind);
 
 /**
  * @return Whether this type of expression has children.

src/opt.c

@@ -1337,7 +1337,7 @@ static struct bfs_expr *opt_const(struct bfs_opt *opt, bool value) {
 	static bfs_eval_fn *const fns[] = {eval_false, eval_true};
 	static char *fake_args[] = {"-false", "-true"};
 
-	struct bfs_expr *expr = bfs_expr_new(opt->ctx, fns[value], 1, &fake_args[value]);
+	struct bfs_expr *expr = bfs_expr_new(opt->ctx, fns[value], 1, &fake_args[value], BFS_TEST);
 	return visit_shallow(opt, expr, &annotate);
 }
 
@@ -1351,7 +1351,7 @@ static struct bfs_expr *negate_expr(struct bfs_opt *opt, struct bfs_expr *expr,
 		return opt_const(opt, true);
 	}
 
-	struct bfs_expr *ret = bfs_expr_new(opt->ctx, eval_not, 1, argv);
+	struct bfs_expr *ret = bfs_expr_new(opt->ctx, eval_not, 1, argv, BFS_OPERATOR);
 	if (!ret) {
 		return NULL;
 	}