diff --git a/lib/parser.c b/lib/parser.c
index 2c4d5a4..0b2b56c 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -101,10 +101,10 @@ static int parse_term(const char *input, int rem, term_t *out)
 	} else if ('(' == input[0]) {
 		++used;
 
-		result = parse_regex(input + used, rem - used, &out->regex);
+		result = parse_expr(input + used, rem - used, &out->subexpr);
 		if (result < 0)
 			return -1;
-		out->type = TERM_TYPE_REGEX;
+		out->type = TERM_TYPE_SUBEXPR;
 		used += result;
 
 		if (')' != input[used])
@@ -178,7 +178,7 @@ static int parse_sequence(const char *input, int rem, sequence_t *out)
 	return out->len > 0 ? used : -1;
 }
 
-int parse_regex(const char *input, int rem, regex_t *out)
+int parse_expr(const char *input, int rem, parse_tree_t *out)
 {
 	int result, used = 0;
 
@@ -190,10 +190,10 @@ int parse_regex(const char *input, int rem, regex_t *out)
 	if (used < rem && '|' == input[used]) {
 		++used;
 
-		out->alternative = malloc(sizeof(regex_t));
+		out->alternative = malloc(sizeof(parse_tree_t));
 		if (NULL == out->alternative)
 			return -1;
-		result = parse_regex(input + used, rem - used, out->alternative);
+		result = parse_expr(input + used, rem - used, out->alternative);
 		if (result < 0)
 			return -1;
 		used += result;
@@ -203,3 +203,38 @@ int parse_regex(const char *input, int rem, regex_t *out)
 
 	return used;
 }
+
+static void class_free(class_t *c)
+{
+	if (NULL != c->contents)
+		free(c->contents);
+}
+
+static void sequence_free(sequence_t *s)
+{
+	if (NULL != s->contents) {
+		for (int i = 0; i < s->len; ++i) {
+			switch (s->contents[i].type) {
+			case TERM_TYPE_CLASS:
+				class_free(&s->contents[i].class);
+				break;
+			case TERM_TYPE_SUBEXPR:
+				parse_tree_free_children(&s->contents[i].subexpr);
+				break;
+			case TERM_TYPE_WILDCARD:
+			case TERM_TYPE_LITERAL:
+				break;
+			}
+		}
+		free(s->contents);
+	}
+}
+
+void parse_tree_free_children(parse_tree_t *t)
+{
+	sequence_free(&t->sequence);
+	if (NULL != t->alternative) {
+		parse_tree_free_children(t->alternative);
+		free(t->alternative);
+	}
+}
diff --git a/lib/parser.h b/lib/parser.h
index b88933c..22e769e 100644
--- a/lib/parser.h
+++ b/lib/parser.h
@@ -6,8 +6,50 @@
 #ifndef PARSER_H
 #define PARSER_H
 
-#include "regex.h"
+#include <stdbool.h>
 
-int parse_regex(const char *input, int rem, regex_t *out);
+typedef struct {
+	bool negated;
+	int count, capacity;
+	char *contents;
+} class_t;
+
+typedef enum {
+	QUANTIFIER_NONE,
+	QUANTIFIER_ZERO_OR_MORE,
+	QUANTIFIER_ONE_OR_MORE,
+	QUANTIFIER_ZERO_OR_ONE,
+} quantifier_t;
+
+typedef enum {
+	TERM_TYPE_WILDCARD,
+	TERM_TYPE_CLASS,
+	TERM_TYPE_LITERAL,
+	TERM_TYPE_SUBEXPR,
+} term_type_t;
+
+struct _term;
+typedef struct {
+	int len, capacity;
+	struct _term *contents;
+} sequence_t;
+
+typedef struct _parse_tree {
+	sequence_t sequence;
+	struct _parse_tree *alternative;
+} parse_tree_t;
+
+typedef struct _term {
+	quantifier_t quantifier;
+	term_type_t type;
+	union {
+		class_t class;
+		char literal;
+		parse_tree_t subexpr;
+	};
+} term_t;
+
+int parse_expr(const char *input, int rem, parse_tree_t *out);
+void parse_tree_free_children(parse_tree_t *t);
 
 #endif
diff --git a/lib/regex.c b/lib/regex.c
deleted file mode 100644
index 2100db9..0000000
--- a/lib/regex.c
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- * Copyright (c) Camden Dixie O'Brien
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-#include "regex.h"
-
-#include <stdlib.h>
-
-static void class_free(class_t *c)
-{
-	if (NULL != c->contents)
-		free(c->contents);
-}
-
-static void sequence_free(sequence_t *s)
-{
-	if (NULL != s->contents) {
-		for (int i = 0; i < s->len; ++i) {
-			switch (s->contents[i].type) {
-			case TERM_TYPE_CLASS:
-				class_free(&s->contents[i].class);
-				break;
-			case TERM_TYPE_REGEX:
-				regex_free_children(&s->contents[i].regex);
-				break;
-			case TERM_TYPE_WILDCARD:
-			case TERM_TYPE_LITERAL:
-				break;
-			}
-		}
-		free(s->contents);
-	}
-}
-
-void regex_free_children(regex_t *r)
-{
-	sequence_free(&r->sequence);
-	if (NULL != r->alternative) {
-		regex_free_children(r->alternative);
-		free(r->alternative);
-	}
-}
diff --git a/lib/regex.h b/lib/regex.h
deleted file mode 100644
index 5d9efe2..0000000
--- a/lib/regex.h
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Copyright (c) Camden Dixie O'Brien
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-#ifndef REGEX_H
-#define REGEX_H
-
-#include <stdbool.h>
-
-typedef struct {
-	bool negated;
-	int count, capacity;
-	char *contents;
-} class_t;
-
-typedef enum {
-	QUANTIFIER_NONE,
-	QUANTIFIER_ZERO_OR_MORE,
-	QUANTIFIER_ONE_OR_MORE,
-	QUANTIFIER_ZERO_OR_ONE,
-} quantifier_t;
-
-typedef enum {
-	TERM_TYPE_WILDCARD,
-	TERM_TYPE_CLASS,
-	TERM_TYPE_LITERAL,
-	TERM_TYPE_REGEX,
-} term_type_t;
-
-struct _term;
-typedef struct {
-	int len, capacity;
-	struct _term *contents;
-} sequence_t;
-
-typedef struct _regex {
-	sequence_t sequence;
-	struct _regex *alternative;
-} regex_t;
-
-typedef struct _term {
-	quantifier_t quantifier;
-	term_type_t type;
-	union {
-		class_t class;
-		char literal;
-		regex_t regex;
-	};
-} term_t;
-
-void regex_free_children(regex_t *r);
-
-#endif
diff --git a/scripts/build.sh b/scripts/build.sh
index 9ec83c1..5bb1c13 100644
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -8,8 +8,7 @@ mkdir -p build
 
 # Build library
 clang $CFLAGS -Ilib -c lib/parser.c -o build/parser.o
-clang $CFLAGS -Ilib -c lib/regex.c -o build/regex.o
-ar -crs build/lib.a build/parser.o build/regex.o
+ar -crs build/lib.a build/parser.o
 
 # Build tests
 clang $CFLAGS -Itests -c tests/testing.c -o build/testing.o
diff --git a/tests/parser_tests.c b/tests/parser_tests.c
index 3165eae..7b74890 100644
--- a/tests/parser_tests.c
+++ b/tests/parser_tests.c
@@ -6,243 +6,243 @@
 #include "parser.h"
 #include "testing.h"
 
-#define PARSE_REGEX_STRING(s, r) parse_regex(s, strlen(s), r)
+#define PARSE_EXPR_STRING(s, r) parse_expr(s, strlen(s), r)
 
 static void a_has_no_alternative(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("a", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("a", &t);
 	ASSERT_NE(-1, result);
-	ASSERT_NULL(r.alternative);
-	regex_free_children(&r);
+	ASSERT_NULL(t.alternative);
+	parse_tree_free_children(&t);
 }
 
 static void a_pipe_b_has_alternative(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("a|b", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("a|b", &t);
 	ASSERT_NE(-1, result);
-	ASSERT_NOT_NULL(r.alternative);
-	regex_free_children(&r);
+	ASSERT_NOT_NULL(t.alternative);
+	parse_tree_free_children(&t);
 }
 
 static void a_pipe_b_pipe_c_result_alternative_has_alternative(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("a|b|c", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("a|b|c", &t);
 	ASSERT_NE(-1, result);
-	ASSERT_NOT_NULL(r.alternative);
-	ASSERT_NOT_NULL(r.alternative->alternative);
-	regex_free_children(&r);
+	ASSERT_NOT_NULL(t.alternative);
+	ASSERT_NOT_NULL(t.alternative->alternative);
+	parse_tree_free_children(&t);
 }
 
 static void a_is_parsed_as_unquantified_literal(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("a", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("a", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[0].type);
-	ASSERT_EQ('a', r.sequence.contents[0].literal);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, t.sequence.contents[0].type);
+	ASSERT_EQ('a', t.sequence.contents[0].literal);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void b_is_parsed_as_unquantified_literal(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("b", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("b", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[0].type);
-	ASSERT_EQ('b', r.sequence.contents[0].literal);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, t.sequence.contents[0].type);
+	ASSERT_EQ('b', t.sequence.contents[0].literal);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void abc_is_parsed_as_sequence_of_unquantified_literals(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("abc", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("abc", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(3, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[0].type);
-	ASSERT_EQ('a', r.sequence.contents[0].literal);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[1].quantifier);
-	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[1].type);
-	ASSERT_EQ('b', r.sequence.contents[1].literal);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[2].quantifier);
-	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[2].type);
-	ASSERT_EQ('c', r.sequence.contents[2].literal);
+	ASSERT_EQ(3, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, t.sequence.contents[0].type);
+	ASSERT_EQ('a', t.sequence.contents[0].literal);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[1].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, t.sequence.contents[1].type);
+	ASSERT_EQ('b', t.sequence.contents[1].literal);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[2].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, t.sequence.contents[2].type);
+	ASSERT_EQ('c', t.sequence.contents[2].literal);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void dot_is_parsed_as_unquantified_wildcard_term(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING(".", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING(".", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_WILDCARD, r.sequence.contents[0].type);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_WILDCARD, t.sequence.contents[0].type);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void backslash_dot_is_parsed_as_unquantified_literal(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("\\.", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("\\.", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[0].type);
-	ASSERT_EQ('.', r.sequence.contents[0].literal);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, t.sequence.contents[0].type);
+	ASSERT_EQ('.', t.sequence.contents[0].literal);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void backslash_backslash_is_parsed_as_unquantified_literal(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("\\\\", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("\\\\", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[0].type);
-	ASSERT_EQ('\\', r.sequence.contents[0].literal);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, t.sequence.contents[0].type);
+	ASSERT_EQ('\\', t.sequence.contents[0].literal);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
-static void a_pipe_b_in_parens_is_parsed_as_regex_term(void)
+static void a_pipe_b_in_parens_is_parsed_as_subexpr_term(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("(a|b)", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("(a|b)", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_REGEX, r.sequence.contents[0].type);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_SUBEXPR, t.sequence.contents[0].type);
 
-	const regex_t *inner = &r.sequence.contents[0].regex;
+	const parse_tree_t *inner = &t.sequence.contents[0].subexpr;
 	ASSERT_EQ(1, inner->sequence.len);
 	ASSERT_EQ(QUANTIFIER_NONE, inner->sequence.contents[0].quantifier);
 	ASSERT_EQ(TERM_TYPE_LITERAL, inner->sequence.contents[0].type);
 	ASSERT_EQ('a', inner->sequence.contents[0].literal);
 
-	const regex_t *inner_alt = inner->alternative;
+	const parse_tree_t *inner_alt = inner->alternative;
 	ASSERT_EQ(1, inner->sequence.len);
 	ASSERT_EQ(QUANTIFIER_NONE, inner_alt->sequence.contents[0].quantifier);
 	ASSERT_EQ(TERM_TYPE_LITERAL, inner_alt->sequence.contents[0].type);
 	ASSERT_EQ('b', inner_alt->sequence.contents[0].literal);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
-static void a_in_parens_b_is_parsed_as_sequence_with_regex_term(void)
+static void a_in_parens_b_is_parsed_as_sequence_with_subexpr_term(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("(a)b", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("(a)b", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(2, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_REGEX, r.sequence.contents[0].type);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[1].quantifier);
-	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[1].type);
-	ASSERT_EQ('b', r.sequence.contents[1].literal);
+	ASSERT_EQ(2, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_SUBEXPR, t.sequence.contents[0].type);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[1].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, t.sequence.contents[1].type);
+	ASSERT_EQ('b', t.sequence.contents[1].literal);
 
-	const regex_t *inner = &r.sequence.contents[0].regex;
+	const parse_tree_t *inner = &t.sequence.contents[0].subexpr;
 	ASSERT_EQ(1, inner->sequence.len);
 	ASSERT_EQ(QUANTIFIER_NONE, inner->sequence.contents[0].quantifier);
 	ASSERT_EQ(TERM_TYPE_LITERAL, inner->sequence.contents[0].type);
 	ASSERT_EQ('a', inner->sequence.contents[0].literal);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void dot_star_is_parsed_as_zero_or_more_wildcard(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING(".*", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING(".*", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_ZERO_OR_MORE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_WILDCARD, r.sequence.contents[0].type);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_ZERO_OR_MORE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_WILDCARD, t.sequence.contents[0].type);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void dot_plus_is_parsed_as_one_or_more_wildcard(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING(".+", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING(".+", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_ONE_OR_MORE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_WILDCARD, r.sequence.contents[0].type);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_ONE_OR_MORE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_WILDCARD, t.sequence.contents[0].type);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void dot_question_mark_is_parsed_as_zero_or_one_wildcard(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING(".?", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING(".?", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_ZERO_OR_ONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_WILDCARD, r.sequence.contents[0].type);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_ZERO_OR_ONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_WILDCARD, t.sequence.contents[0].type);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void a_in_brackets_is_parsed_as_class_containing_only_a(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("[a]", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("[a]", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_CLASS, r.sequence.contents[0].type);
-	ASSERT_FALSE(r.sequence.contents[0].class.negated);
-	ASSERT_EQ(1, r.sequence.contents[0].class.count);
-	ASSERT_NOT_NULL(r.sequence.contents[0].class.contents);
-	ASSERT_EQ('a', r.sequence.contents[0].class.contents[0]);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_CLASS, t.sequence.contents[0].type);
+	ASSERT_FALSE(t.sequence.contents[0].class.negated);
+	ASSERT_EQ(1, t.sequence.contents[0].class.count);
+	ASSERT_NOT_NULL(t.sequence.contents[0].class.contents);
+	ASSERT_EQ('a', t.sequence.contents[0].class.contents[0]);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 static void caret_a_in_brackets_parses_as_negated_class(void)
 {
-	regex_t r;
-	const int result = PARSE_REGEX_STRING("[^a]", &r);
+	parse_tree_t t;
+	const int result = PARSE_EXPR_STRING("[^a]", &t);
 	ASSERT_NE(-1, result);
 
-	ASSERT_EQ(1, r.sequence.len);
-	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
-	ASSERT_EQ(TERM_TYPE_CLASS, r.sequence.contents[0].type);
-	ASSERT_TRUE(r.sequence.contents[0].class.negated);
-	ASSERT_EQ(1, r.sequence.contents[0].class.count);
-	ASSERT_NOT_NULL(r.sequence.contents[0].class.contents);
-	ASSERT_EQ('a', r.sequence.contents[0].class.contents[0]);
+	ASSERT_EQ(1, t.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, t.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_CLASS, t.sequence.contents[0].type);
+	ASSERT_TRUE(t.sequence.contents[0].class.negated);
+	ASSERT_EQ(1, t.sequence.contents[0].class.count);
+	ASSERT_NOT_NULL(t.sequence.contents[0].class.contents);
+	ASSERT_EQ('a', t.sequence.contents[0].class.contents[0]);
 
-	regex_free_children(&r);
+	parse_tree_free_children(&t);
 }
 
 int main(void)
@@ -257,8 +257,8 @@ int main(void)
 	dot_is_parsed_as_unquantified_wildcard_term();
 	backslash_dot_is_parsed_as_unquantified_literal();
 	backslash_backslash_is_parsed_as_unquantified_literal();
-	a_pipe_b_in_parens_is_parsed_as_regex_term();
-	a_in_parens_b_is_parsed_as_sequence_with_regex_term();
+	a_pipe_b_in_parens_is_parsed_as_subexpr_term();
+	a_in_parens_b_is_parsed_as_sequence_with_subexpr_term();
 	dot_star_is_parsed_as_zero_or_more_wildcard();
 	dot_plus_is_parsed_as_one_or_more_wildcard();
 	dot_question_mark_is_parsed_as_zero_or_one_wildcard();