From d0c9b43f6ea0d20f91d06c007215a01d75480487 Mon Sep 17 00:00:00 2001
From: Andrea Zagli <azagli@libero.it>
Date: Sun, 22 Aug 2021 08:49:13 +0200
Subject: [PATCH] Added callback for missing col value.

---
 main.go | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/main.go b/main.go
index e4de04c..7de1eef 100644
--- a/main.go
+++ b/main.go
@@ -7,10 +7,13 @@ import (
 	_ "github.com/mattn/go-sqlite3"
 )
 
+type missingCol func (map[string]interface{}) interface{}
+
 type column struct {
 	name string
 	title string
 	align int
+	toCall missingCol
 }
 
 type grid struct {
@@ -39,11 +42,12 @@ func (g *grid) getRowFromDb (m map[string]interface{}) string {
 
 	for _, c := range g.cols {
 		v, ok := m[c.name]
-		if ok {
-			ret += fmt.Sprintf("\t<td>%v</td>\n", v)
-		} else {
-			ret += fmt.Sprintf("\t<td></td>\n")
+		if !ok {
+			if c.toCall != nil {
+				v = c.toCall(m)
+			}
 		}
+		ret += fmt.Sprintf("\t<td>%v</td>\n", v)
 	}
 
 	ret += "</tr>\n"
@@ -51,6 +55,12 @@ func (g *grid) getRowFromDb (m map[string]interface{}) string {
 	return ret
 }
 
+func missing (row map[string]interface{}) interface{} {
+	ret := "<button>Save</button>"
+
+	return ret
+}
+
 func main() {
 	var g grid
 
@@ -67,6 +77,7 @@ func main() {
 	g.addColumn(c)
 
 	c = column{name: "btn", title: "Buttons"}
+	c.toCall = missing
 	g.addColumn(c)
 
 	fmt.Println (g)
-- 
2.49.0