From d45bd4523c98b9190de5cd7a43ee32087451fe5f Mon Sep 17 00:00:00 2001
From: brettlangdon <brett@blangdon.com>
Date: Sat, 21 Nov 2015 18:59:40 -0500
Subject: [PATCH 1/2] Display help text for positional arguments

---
 usage.go      | 15 ++++++++++++++-
 usage_test.go | 27 +++++++++++++++++++++++++--
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/usage.go b/usage.go
index 9404015..2c38fe7 100644
--- a/usage.go
+++ b/usage.go
@@ -68,11 +68,24 @@ func (p *Parser) WriteHelp(w io.Writer) {
 
 	p.WriteUsage(w)
 
+	// the width of the left column
+	const colWidth = 25
+
 	// write the list of positionals
 	if len(positionals) > 0 {
 		fmt.Fprint(w, "\npositional arguments:\n")
 		for _, spec := range positionals {
-			fmt.Fprintf(w, "  %s\n", spec.long)
+			left := "  " + spec.long
+			fmt.Fprint(w, left)
+			if spec.help != "" {
+				if len(left)+2 < colWidth {
+					fmt.Fprint(w, strings.Repeat(" ", colWidth-len(left)))
+				} else {
+					fmt.Fprint(w, "\n"+strings.Repeat(" ", colWidth))
+				}
+				fmt.Fprint(w, spec.help)
+			}
+			fmt.Fprint(w, "\n")
 		}
 	}
 
diff --git a/usage_test.go b/usage_test.go
index 5a9199c..4a56e6e 100644
--- a/usage_test.go
+++ b/usage_test.go
@@ -16,7 +16,7 @@ func TestWriteUsage(t *testing.T) {
 
 positional arguments:
   input
-  output
+  output                 positional output
 
 options:
   --verbose, -v          verbosity level
@@ -27,7 +27,7 @@ options:
 `
 	var args struct {
 		Input    string   `arg:"positional"`
-		Output   []string `arg:"positional"`
+		Output   []string `arg:"positional,help:positional output"`
 		Verbose  bool     `arg:"-v,help:verbosity level"`
 		Dataset  string   `arg:"help:dataset to use"`
 		Optimize int      `arg:"-O,help:optimization level"`
@@ -45,3 +45,26 @@ options:
 	p.WriteHelp(&help)
 	assert.Equal(t, expectedHelp, help.String())
 }
+
+func TestUsageLongPositionalWithHelp(t *testing.T) {
+	expectedHelp := `usage: example VERYLONGPOSITIONALWITHHELP
+
+positional arguments:
+  verylongpositionalwithhelp
+                         this positional argument is very long
+
+options:
+  --help, -h             display this help and exit
+`
+	var args struct {
+		VeryLongPositionalWithHelp string `arg:"positional,help:this positional argument is very long"`
+	}
+
+	p, err := NewParser(&args)
+	require.NoError(t, err)
+
+	os.Args[0] = "example"
+	var help bytes.Buffer
+	p.WriteHelp(&help)
+	assert.Equal(t, expectedHelp, help.String())
+}

From 4197d283e41bbce1a2cac20ea56fd1156a677db1 Mon Sep 17 00:00:00 2001
From: Alex Flint <alex.flint@gmail.com>
Date: Mon, 18 Jan 2016 08:24:21 -0800
Subject: [PATCH 2/2] extract common colWidth constant

---
 usage.go | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/usage.go b/usage.go
index 65f7c2d..61f0ad6 100644
--- a/usage.go
+++ b/usage.go
@@ -9,6 +9,9 @@ import (
 	"strings"
 )
 
+// the width of the left column
+const colWidth = 25
+
 // Fail prints usage information to stderr and exits with non-zero status
 func (p *Parser) Fail(msg string) {
 	p.WriteUsage(os.Stderr)
@@ -69,9 +72,6 @@ func (p *Parser) WriteHelp(w io.Writer) {
 
 	p.WriteUsage(w)
 
-	// the width of the left column
-	const colWidth = 25
-
 	// write the list of positionals
 	if len(positionals) > 0 {
 		fmt.Fprint(w, "\npositional arguments:\n")
@@ -101,7 +101,6 @@ func (p *Parser) WriteHelp(w io.Writer) {
 }
 
 func printOption(w io.Writer, spec *spec) {
-	const colWidth = 25
 	left := "  " + synopsis(spec, "--"+spec.long)
 	if spec.short != "" {
 		left += ", " + synopsis(spec, "-"+spec.short)