diff --git a/src/source.h b/src/source.h
index 3219e1c..df049bb 100644
--- a/src/source.h
+++ b/src/source.h
@@ -19,9 +19,9 @@ struct source_tree_iterator { struct tree_source_iterator _; };
 
 struct sourcelist_array { struct source *data; size_t size, capacity; };
 
-struct sourcelook_bucket;
-struct sourcelook_table {
-	struct sourcelook_bucket *buckets;
+struct sourcemap_bucket;
+struct sourcemap_table {
+	struct sourcemap_bucket *buckets;
 	uint32_t log_capacity, size, top;
 };
 
@@ -33,7 +33,7 @@ struct sourcelook_table {
 #include <stddef.h>
 struct sources {
 	struct sourcelist_array list;
-	struct sourcelook_table look;
+	struct sourcemap_table map;
 	struct source_tree dates;
 };
 struct source *sources_add(struct sources *, const union line64);
diff --git a/src/source.re.c b/src/source.re.c
index 91609df..1d5dd92 100644
--- a/src/source.re.c
+++ b/src/source.re.c
@@ -10,6 +10,7 @@
 #include <assert.h>
 
 
+/* `sourcelist` is an array of all the sources. */
 static void sourcelist_to_string(const struct source *const s,
 	char (*const z)[12]) {
 	const char *a = s->name.a, *b;
@@ -24,24 +25,29 @@ static void sourcelist_to_string(const struct source *const s,
 #include "../src/array.h"
 
 
-static int sourcelook_is_equal(const struct pair a, const struct pair b)
+/* `sourcemap` maps from substring keywords to indices in `sourcelist`. */
+static void sourcemap_to_string(const struct pair key, const size_t i,
+	char (*const a)[12]) { (void)key; sprintf(*a, "%zu", i); }
+static int sourcemap_is_equal(const struct pair a, const struct pair b)
 	{ return pair_is_equal(a, b); }
-static uint32_t sourcelook_hash(const struct pair p) { return pair_djb2(p); }
-#define TABLE_NAME sourcelook
+static uint32_t sourcemap_hash(const struct pair p) { return pair_djb2(p); }
+#define TABLE_NAME sourcemap
 #define TABLE_KEY struct pair
 #define TABLE_UINT uint32_t
-#define TABLE_VALUE size_t /* Index into `lookup_sources`. */
+#define TABLE_VALUE size_t /* Index into source list. */
 #define TABLE_DEFAULT 0
+#define TABLE_TO_STRING
 #include "../src/table.h"
 
 
+/* `source` is a tree mapping from date-line to indices in `sourcelist`. */
 static void source_to_string(const union line64 line, const size_t *const u,
 	char (*const a)[12]) { (void)u; date32_to_string(line.date, a); }
 static int source_compare(const union line64 a, const union line64 b)
 	{ return a.u64 > b.u64; }
 #define TREE_NAME source
 #define TREE_KEY union line64
-#define TREE_VALUE size_t /* Index into `lookup_sources`. */
+#define TREE_VALUE size_t /* Index into source list. */
 #define TREE_COMPARE
 #define TREE_TO_STRING
 #include "../src/tree.h"
@@ -89,9 +95,14 @@ static int scan(union date32 date, const char *const buffer,
 		<source> @s0 keyword @s1 / "\n" => skip { also_add_to_tree: {
 			struct pair p = pair(s0, s1);
 			size_t i;
-			if(!(i = sourcelook_table_get(&s->look, p)))
+			//const union line64 key = { ... };
+			if(!(i = sourcemap_table_get(&s->map, p)))
 				{ why = "keyword not introduced"; goto catch; }
-			printf("extracted <%.*s>\n", (int)(s1 - s0), s0);
+			/*switch(source_tree_assign(&s->source, )) {
+				...
+			}*/
+			date32_to_string(date, &datestr);
+			printf("%s: <%.*s>\n", datestr, (int)(s1 - s0), s0);
 			continue;
 		} }
 		/* This is lazy and will pickup trailing spaces. */
@@ -99,7 +110,7 @@ static int scan(union date32 date, const char *const buffer,
 			struct pair keyword = pair(s0, s1);
 			size_t *idx;
 			struct source *source;
-			switch(sourcelook_table_assign(&s->look, keyword, &idx)) {
+			switch(sourcemap_table_assign(&s->map, keyword, &idx)) {
 			case TABLE_PRESENT: errno = EDOM; why = "new keyword already used";
 			case TABLE_ERROR: goto catch; /* /\ _Sic_. */
 			case TABLE_ABSENT: break; /* Good. */
@@ -122,18 +133,17 @@ catch:
 		"%s line %zu: %s.\n", buffer, datestr, line, why);
 	return 0;
 }
-/** Dynamic memory allocation for `s` will be zero, <fn:sources_is_valid> will
- be false. */
+/** Dynamic memory allocation for `s` will be zero. */
 void sources_(struct sources *const s) {
 	if(!s) return;
 	source_tree_(&s->dates);
-	sourcelook_table_(&s->look);
+	sourcemap_table_(&s->map);
 	sourcelist_array_(&s->list);
 }
 
 struct sources sources(struct journal *const j) {
 	struct sources s
-		= { sourcelist_array(), sourcelook_table(), source_tree() };
+		= { sourcelist_array(), sourcemap_table(), source_tree() };
 	struct journal_iterator it;
 	union date32 k;
 	const char *v;
@@ -145,7 +155,10 @@ struct sources sources(struct journal *const j) {
 	}
 	it = journal_begin(j);
 	while(journal_next(&it, &k, &v)) if(!scan(k, v, &s)) goto catch;
-	printf("%s\n", sourcelist_array_to_string(&s.list));
+	fprintf(stderr, "List of sources: %s.\n"
+		"Mapped to indices: %s.\n"
+		"Date-line tree: %s.\n", sourcelist_array_to_string(&s.list),
+		sourcemap_table_to_string(&s.map), source_tree_to_string(&s.dates));
 	goto finally;
 catch:
 	sources_(&s);
diff --git a/test/test_source.c b/test/test_source.c
index 4448892..9c40ed3 100644
--- a/test/test_source.c
+++ b/test/test_source.c
@@ -11,7 +11,6 @@ int main(void) {
 	struct journal j = journal();
 	struct sources s = sources(&j);
 	if(errno) goto catch;
-	printf("***success\n");
 	goto finally;
 catch:
 	success = EXIT_FAILURE, perror("source");