lib: add isAlpha

* lib/str.go (isAlpha): New function.

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/str.go b/lib/str.go
index 84f80ab..7129136 100644
--- a/lib/str.go
+++ b/lib/str.go
@@ -28,3 +28,13 @@ func stripSpaceChars(s string) string {
 	}
 	return ss
 }
+
+func isAlpha(c byte) bool {
+	switch {
+	case 'A' <= c && c <= 'Z':
+		return true
+	case 'a' <= c && c <= 'z':
+		return true
+	}
+	return false
+}