diff --git a/.gitignore b/.gitignore
index b8a3ff6..8365745 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@
 /samu
 /.ninja_deps
 /.ninja_log
+.vscode/
diff --git a/graph.h b/graph.h
index dc7306b..bde4570 100644
--- a/graph.h
+++ b/graph.h
@@ -8,6 +8,7 @@ enum {
 	MTIME_MISSING = -2,
 };
 
+/* corresponds to a file */
 struct node {
 	/* shellpath is the escaped shell path, and is populated as needed by nodepath */
 	struct string *path, *shellpath;
@@ -15,11 +16,11 @@ struct node {
 	/* modification time of file (in nanoseconds) and build log entry (in seconds) */
 	int64_t mtime, logmtime;
 
-	/* generating edge and dependent edges.
-	 *
-	 * only gen and nuse are set in parse.c:parseedge; use is allocated and
-	 * populated in build.c:computedirty. */
-	struct edge *gen, **use;
+	/* edge that builds this node */
+	struct edge *gen;
+	/* list of edges that use this node as input, allocated and populated in graph.c:nodeuse */
+	struct edge **use;
+	/* number of edges in this.use */
 	size_t nuse;
 
 	/* command hash used to build this output, read from build log */
diff --git a/parse.c b/parse.c
index 932a573..0977499 100644
--- a/parse.c
+++ b/parse.c
@@ -78,6 +78,7 @@ parseedge(struct scanner *s, struct environment *env)
 
 	e = mkedge(env);
 
+	/* scan outputs */
 	for (out = NULL, end = &out; (str = scanstring(s, true)); ++e->nout)
 		pushstr(&end, str);
 	e->outimpidx = e->nout;
@@ -88,6 +89,8 @@ parseedge(struct scanner *s, struct environment *env)
 	if (e->nout == 0)
 		scanerror(s, "expected output path");
 	scanchar(s, ':');
+
+	/* scan rule name and inputs */
 	name = scanname(s);
 	e->rule = envrule(env, name);
 	if (!e->rule)
@@ -107,6 +110,8 @@ parseedge(struct scanner *s, struct environment *env)
 		for (; (str = scanstring(s, true)); ++e->nin)
 			pushstr(&end, str);
 	}
+
+	/* scan variables for the build rule */
 	scannewline(s);
 	while (scanindent(s)) {
 		name = scanname(s);
@@ -115,6 +120,7 @@ parseedge(struct scanner *s, struct environment *env)
 		envaddvar(e->env, name, val);
 	}
 
+	/* evaluate output strings and make output nodes */
 	e->out = xreallocarray(NULL, e->nout, sizeof(e->out[0]));
 	for (i = 0; i < e->nout; out = str) {
 		str = out->next;