diff --git a/src/cron/expression.c.v b/src/cron/expression.c.v
index 0698432..cd4b8b0 100644
--- a/src/cron/expression.c.v
+++ b/src/cron/expression.c.v
@@ -36,6 +36,7 @@ enum ParseError as u8 {
 	too_many_parts = 4
 }
 
+// str returns the string representation of a ParseError.
 fn (e ParseError) str() string {
 	return match e {
 		.ok { '' }
diff --git a/src/cron/expression.v b/src/cron/expression.v
index 4a0d04c..c463d06 100644
--- a/src/cron/expression.v
+++ b/src/cron/expression.v
@@ -2,11 +2,13 @@ module cron
 
 import time
 
+// free the memory associated with the Expression.
 [unsafe]
 pub fn (ce &Expression) free() {
 	C.ce_free(ce)
 }
 
+// parse_expression parses a string into an Expression.
 pub fn parse_expression(exp string) !&Expression {
 	out := C.ce_init()
 	res := C.ce_parse_expression(out, exp.str)
@@ -18,6 +20,8 @@ pub fn parse_expression(exp string) !&Expression {
 	return out
 }
 
+// next calculates the next occurence of the cron schedule, given a reference
+// point.
 pub fn (ce &Expression) next(ref time.Time) time.Time {
 	st := SimpleTime{
 		year: ref.year
@@ -39,6 +43,8 @@ pub fn (ce &Expression) next(ref time.Time) time.Time {
 	})
 }
 
+// next_from_now calculates the next occurence of the cron schedule with the
+// current time as reference.
 pub fn (ce &Expression) next_from_now() time.Time {
 	out := SimpleTime{}
 	C.ce_next_from_now(&out, ce)
diff --git a/src/cron/expression_test.v b/src/cron/expression_test.v
index c016b72..9863ef5 100644
--- a/src/cron/expression_test.v
+++ b/src/cron/expression_test.v
@@ -37,7 +37,7 @@ fn test_next_simple() ! {
 
 fn test_leading_star() {
 	mut x := false
- 
+
 	parse_expression('*5 8') or { x = true }
 
 	assert x