From 70aec47e6b4e68a0638c983bebb295c88482c564 Mon Sep 17 00:00:00 2001
From: rwxrob <rob@rwx.gg>
Date: Thu, 24 Feb 2022 22:25:04 -0500
Subject: [PATCH] Add check.Blank

---
 check/check.go      | 21 +++++++++++++++++++++
 check/check_test.go | 27 +++++++++++++++++++++++++++
 comp/help.go        | 25 +++++++++++++++++++++++++
 comp/standard.go    |  3 ++-
 4 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 check/check.go
 create mode 100644 check/check_test.go
 create mode 100644 comp/help.go

diff --git a/check/check.go b/check/check.go
new file mode 100644
index 0000000..3492c2a
--- /dev/null
+++ b/check/check.go
@@ -0,0 +1,21 @@
+package check
+
+// Blank checks that the passed string, []byte (or slice of either)
+// contains something besides an empty string.
+func Blank(i interface{}) bool {
+	switch v := i.(type) {
+	case nil:
+		return false
+	case string:
+		return v != ""
+	case []byte:
+		return string(v) != ""
+	case []string:
+		return v != nil && len(v) != 0 && v[0] != ""
+	case [][]byte:
+		return v != nil && len(v) != 0 && string(v[0]) != ""
+	default:
+		panic("cannot check if type is blank")
+	}
+	return false
+}
diff --git a/check/check_test.go b/check/check_test.go
new file mode 100644
index 0000000..a557970
--- /dev/null
+++ b/check/check_test.go
@@ -0,0 +1,27 @@
+package check_test
+
+import (
+	"fmt"
+
+	"github.com/rwxrob/bonzai/check"
+)
+
+func ExampleBlank() {
+	fmt.Println(check.Blank(""))
+	fmt.Println(check.Blank(nil))
+	fmt.Println(check.Blank([]string{""}))
+	fmt.Println(check.Blank([][]byte{}))
+	// and now for true
+	fmt.Println(check.Blank("some"))
+	fmt.Println(check.Blank([]string{"some"}))
+	fmt.Println(check.Blank([][]byte{{'a'}}))
+
+	// Output:
+	// false
+	// false
+	// false
+	// false
+	// true
+	// true
+	// true
+}
diff --git a/comp/help.go b/comp/help.go
new file mode 100644
index 0000000..369bff7
--- /dev/null
+++ b/comp/help.go
@@ -0,0 +1,25 @@
+// Copyright 2022 Robert S. Muhlestein.
+// SPDX-License-Identifier: Apache-2.0
+
+package comp
+
+import (
+	"github.com/rwxrob/bonzai/check"
+	"github.com/rwxrob/bonzai/filter"
+)
+
+func Help(x Command, args ...string) []string {
+
+	// check for unique first argument command
+	if check.Blank(args) {
+		return []string{x.GetName()}
+	}
+
+	// build list of params and other keys
+	list := []string{}
+	list = append(list, x.GetParams()...)
+	// FIXME GetCaller nil check
+	list = append(list, filter.Keys(x.GetCaller().GetOther())...)
+
+	return filter.HasPrefix(list, args[0])
+}
diff --git a/comp/standard.go b/comp/standard.go
index 08a3959..18deca7 100644
--- a/comp/standard.go
+++ b/comp/standard.go
@@ -4,6 +4,7 @@
 package comp
 
 import (
+	"github.com/rwxrob/bonzai/check"
 	"github.com/rwxrob/bonzai/filter"
 )
 
@@ -28,7 +29,7 @@ func Standard(x Command, args ...string) []string {
 	}
 
 	// not sure we've completed the command name itself yet
-	if args == nil || len(args) == 0 {
+	if check.Blank(args) {
 		return []string{x.GetName()}
 	}