From 619f942fae801862f1bda8d471f5ec049ae28243 Mon Sep 17 00:00:00 2001
From: Charles Iliya Krempeaux <iamreiver@gmail.com>
Date: Wed, 4 Oct 2023 17:36:46 +0900
Subject: [PATCH] initial commits

---
 alpha.go      | 18 +++++++++++++
 alpha_test.go | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 alpha.go
 create mode 100644 alpha_test.go

diff --git a/alpha.go b/alpha.go
new file mode 100644
index 0000000..f730577
--- /dev/null
+++ b/alpha.go
@@ -0,0 +1,18 @@
+package rfc2234
+
+// IsAlpha returns true if the value of 'r' matches 'ALPHA' as defined in IETF RFC-2234:
+//
+//	ALPHA =  %x41-5A / %x61-7A   ; A-Z / a-z
+func IsAlpha(r rune) bool {
+	if 'z' < r {
+		return false
+	}
+	if r < 'A' {
+		return false
+	}
+	if 'Z' < r && r < 'a'{
+		return false
+	}
+
+	return true
+}
diff --git a/alpha_test.go b/alpha_test.go
new file mode 100644
index 0000000..693098f
--- /dev/null
+++ b/alpha_test.go
@@ -0,0 +1,75 @@
+package rfc2234_test
+
+import (
+	"testing"
+
+	"sourcecode.social/reiver/go-rfc2234"
+)
+
+func TestIsAlpha(t *testing.T) {
+
+	tests := []struct{
+		Rune rune
+		Expected bool
+	}{
+	}
+
+	for r:=rune(0); r < 'A'; r++ {
+		tests = append(tests, struct{
+			Rune rune
+			Expected bool
+		}{
+			Rune: r,
+			Expected: false,
+		})
+	}
+	for r:='A'; r <= 'Z'; r++ {
+		tests = append(tests, struct{
+			Rune rune
+			Expected bool
+		}{
+			Rune: r,
+			Expected: true,
+		})
+	}
+	for r:='Z'+1; r < 'a'; r++ {
+		tests = append(tests, struct{
+			Rune rune
+			Expected bool
+		}{
+			Rune: r,
+			Expected: false,
+		})
+	}
+	for r:='a'; r <= 'z'; r++ {
+		tests = append(tests, struct{
+			Rune rune
+			Expected bool
+		}{
+			Rune: r,
+			Expected: true,
+		})
+	}
+	for r:='z'+1; r <= rune(127); r++ {
+		tests = append(tests, struct{
+			Rune rune
+			Expected bool
+		}{
+			Rune: r,
+			Expected: false,
+		})
+	}
+
+	for testNumber, test := range tests {
+		actual := rfc2234.IsAlpha(test.Rune)
+		expected := test.Expected
+
+		if expected != actual {
+			t.Errorf("For test #%d, the actual value for rfc2234.IsAlpha() is not what was expected.", testNumber)
+			t.Logf("EXPECTED: %t", expected)
+			t.Logf("ACTUAL:   %t", actual)
+			t.Logf("RUNE: (%U) %q", test.Rune, string(test.Rune))
+			continue
+		}
+	}
+}