added -k parameter to sort by columns

cmd/root.go

@@ -90,6 +90,7 @@ func init() {
 	rootCmd.PersistentFlags().BoolVarP(&ShowManual, "man", "m", false, "Display manual page")
 	rootCmd.PersistentFlags().StringVarP(&lib.Separator, "separator", "s", lib.DefaultSeparator, "Custom field separator")
 	rootCmd.PersistentFlags().StringVarP(&lib.Columns, "columns", "c", "", "Only show the speficied columns (separated by ,)")
+	rootCmd.PersistentFlags().IntVarP(&lib.SortByColumn, "sort-by", "k", 0, "Sort by column (default: 1)")
 
 	// output flags, only 1 allowed, hidden, since just short cuts
 	rootCmd.PersistentFlags().BoolVarP(&lib.OutflagExtended, "extended", "X", false, "Enable extended output")

cmd/tablizer.go

@@ -20,6 +20,7 @@ SYNOPSIS
           -M, --markdown           Enable markdown table output
           -O, --orgtbl             Enable org-mode table output
           -s, --separator string   Custom field separator
+          -k, --sort-by int        Sort by column (default: 1)
           -v, --version            Print program version
 
 DESCRIPTION
@@ -74,6 +75,10 @@ DESCRIPTION
     By default, if a pattern has been speficied, matches will be
     highlighted. You can disable this behavior with the -N option.
 
+    Use the -k option to specify by which column to sort the tabular data
+    (as in GNU sort(1)). The default sort column is the first one. To
+    disable sorting at all, supply 0 (Zero) to -k.
+
     Finally the -d option enables debugging output which is mostly usefull
     for the developer.
 

lib/common.go

@@ -68,10 +68,22 @@ var (
 	validOutputmodes = "(orgtbl|markdown|extended|ascii)"
 
 	// main program version
-	Version = "v1.0.7"
+	Version = "v1.0.8"
 
 	// generated  version string, used  by -v contains  lib.Version on
 	//  main  branch,   and  lib.Version-$branch-$lastcommit-$date  on
 	// development branch
 	VERSION string
+
+	// sorting
+	SortByColumn int
 )
+
+// contains a whole parsed table
+type Tabdata struct {
+	maxwidthHeader int      // longest header
+	maxwidthPerCol []int    // max width per column
+	columns        int      // count
+	headers        []string // [ "ID", "NAME", ...]
+	entries        [][]string
+}

lib/parser.go

@@ -27,15 +27,6 @@ import (
 	"strings"
 )
 
-// contains a whole parsed table
-type Tabdata struct {
-	maxwidthHeader int      // longest header
-	maxwidthPerCol []int    // max width per column
-	columns        int      // count
-	headers        []string // [ "ID", "NAME", ...]
-	entries        [][]string
-}
-
 /*
    Parse tabular input.
 */

lib/printer.go

@@ -26,11 +26,19 @@ import (
 )
 
 func printData(data *Tabdata) {
+	// some output preparations:
+
 	if OutputMode != "shell" {
+		// not needed in eval string
 		numberizeHeaders(data)
 	}
+
+	// remove unwanted columns, if any
 	reduceColumns(data)
 
+	// sort the data
+	sortTable(data, SortByColumn)
+
 	switch OutputMode {
 	case "extended":
 		printExtendedData(data)

lib/printer_test.go

@@ -25,6 +25,20 @@ import (
 	"testing"
 )
 
+func stdout2pipe(t *testing.T) (*os.File, *os.File) {
+	reader, writer, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	origStdout := os.Stdout
+	os.Stdout = writer
+
+	// we need to tell the color mode the io.Writer, even if we don't usw colorization
+	color.SetOutput(writer)
+
+	return origStdout, reader
+}
+
 func TestPrinter(t *testing.T) {
 	startdata := Tabdata{
 		maxwidthHeader: 5,
@@ -51,18 +65,22 @@ func TestPrinter(t *testing.T) {
 		"ascii": `ONE(1)	TWO(2)	THREE(3) 
 asd   	igig  	cxxxncnc	
 19191 	EDD 1 	X`,
+
 		"orgtbl": `|--------+--------+----------|
 | ONE(1) | TWO(2) | THREE(3) |
 |--------+--------+----------|
 | asd    | igig   | cxxxncnc |
 |  19191 | EDD 1  | X        |
 |--------+--------+----------|`,
+
 		"markdown": `| ONE(1) | TWO(2) | THREE(3) |
 |--------|--------|----------|
 | asd    | igig   | cxxxncnc |
 |  19191 | EDD 1  | X        |`,
+
 		"shell": `ONE="asd" TWO="igig" THREE="cxxxncnc"
 ONE="19191" TWO="EDD 1" THREE="X"`,
+
 		"extended": `ONE(1): asd
   TWO(2): igig
 THREE(3): cxxxncnc
@@ -73,16 +91,9 @@ THREE(3): X`,
 	}
 
 	NoColor = true
+	SortByColumn = 0 // disable sorting
 
-	r, w, err := os.Pipe()
-	if err != nil {
-		t.Fatal(err)
-	}
-	origStdout := os.Stdout
-	os.Stdout = w
-
-	// we need to tell the color mode the io.Writer, even if we don't usw colorization
-	color.SetOutput(w)
+	origStdout, reader := stdout2pipe(t)
 
 	for mode, expect := range expects {
 		testname := fmt.Sprintf("print-%s", mode)
@@ -93,7 +104,7 @@ THREE(3): X`,
 			printData(&data)
 
 			buf := make([]byte, 1024)
-			n, err := r.Read(buf)
+			n, err := reader.Read(buf)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -101,7 +112,8 @@ THREE(3): X`,
 			output := strings.TrimSpace(string(buf))
 
 			if output != expect {
-				t.Errorf("output mode: %s, got:\n%s\nwant:\n%s\n (%d <=> %d)", mode, output, expect, len(output), len(expect))
+				t.Errorf("output mode: %s, got:\n%s\nwant:\n%s\n (%d <=> %d)",
+					mode, output, expect, len(output), len(expect))
 			}
 		})
 	}
@@ -110,3 +122,91 @@ THREE(3): X`,
 	os.Stdout = origStdout
 
 }
+
+func TestSortPrinter(t *testing.T) {
+	startdata := Tabdata{
+		maxwidthHeader: 5,
+		maxwidthPerCol: []int{
+			3,
+			3,
+			2,
+		},
+		columns: 3,
+		headers: []string{
+			"ONE", "TWO", "THREE",
+		},
+		entries: [][]string{
+			[]string{
+				"abc", "345", "b1",
+			},
+			[]string{
+				"bcd", "234", "a2",
+			},
+			[]string{
+				"cde", "123", "c3",
+			},
+		},
+	}
+
+	var tests = []struct {
+		data   Tabdata
+		sortby int
+		expect string
+	}{
+		{
+			data:   startdata,
+			sortby: 1,
+			expect: `ONE(1)	TWO(2)	THREE(3) 
+abc   	345   	b1      	
+bcd   	234   	a2      	
+cde   	123   	c3`,
+		},
+
+		{
+			data:   startdata,
+			sortby: 2,
+			expect: `ONE(1)	TWO(2)	THREE(3) 
+cde   	123   	c3      	
+bcd   	234   	a2      	
+abc   	345   	b1`,
+		},
+
+		{
+			data:   startdata,
+			sortby: 3,
+			expect: `ONE(1)	TWO(2)	THREE(3) 
+bcd   	234   	a2      	
+abc   	345   	b1      	
+cde   	123   	c3`,
+		},
+	}
+
+	NoColor = true
+	OutputMode = "ascii"
+	origStdout, reader := stdout2pipe(t)
+
+	for _, tt := range tests {
+		testname := fmt.Sprintf("print-sorted-table-%d", tt.sortby)
+		t.Run(testname, func(t *testing.T) {
+			SortByColumn = tt.sortby
+
+			printData(&tt.data)
+
+			buf := make([]byte, 1024)
+			n, err := reader.Read(buf)
+			if err != nil {
+				t.Fatal(err)
+			}
+			buf = buf[:n]
+			output := strings.TrimSpace(string(buf))
+
+			if output != tt.expect {
+				t.Errorf("sort column: %d, got:\n%s\nwant:\n%s",
+					tt.sortby, output, tt.expect)
+			}
+		})
+	}
+
+	// Restore
+	os.Stdout = origStdout
+}

lib/sort.go

@@ -0,0 +1,46 @@
+/*
+Copyright © 2022 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package lib
+
+import (
+	"sort"
+)
+
+func sortTable(data *Tabdata, col int) {
+	if col <= 0 {
+		// no sorting wanted
+		return
+	}
+
+	col-- // ui starts counting by 1, but use 0 internally
+
+	// sanity checks
+	if len(data.entries) == 0 {
+		return
+	}
+
+	if col >= len(data.headers) {
+		// fall back to default column
+		col = 0
+	}
+
+	// actual sorting
+	sort.SliceStable(data.entries, func(i, j int) bool {
+		return data.entries[i][col] < data.entries[j][col]
+	})
+}

tablizer.1

@@ -133,7 +133,7 @@
 .\" ========================================================================
 .\"
 .IX Title "TABLIZER 1"
-.TH TABLIZER 1 "2022-10-10" "1" "User Commands"
+.TH TABLIZER 1 "2022-10-13" "1" "User Commands"
 .\" For nroff, turn off justification.  Always turn off hyphenation; it makes
 .\" way too many mistakes in technical documents.
 .if n .ad l
@@ -159,6 +159,7 @@ tablizer \- Manipulate tabular output of other programs
 \&      \-M, \-\-markdown           Enable markdown table output
 \&      \-O, \-\-orgtbl             Enable org\-mode table output
 \&      \-s, \-\-separator string   Custom field separator
+\&      \-k, \-\-sort\-by int        Sort by column (default: 1)
 \&      \-v, \-\-version            Print program version
 .Ve
 .SH "DESCRIPTION"
@@ -222,6 +223,10 @@ The numbering can be suppressed by using the \fB\-n\fR option.
 By  default, if  a  \fBpattern\fR  has been  speficied,  matches will  be
 highlighted. You can disable this behavior with the \fB\-N\fR option.
 .PP
+Use the  \fB\-k\fR option to specify  by which column to  sort the tabular
+data (as in \s-1GNU\s0 \fBsort\fR\|(1)). The default sort column is the first one. To
+disable sorting at all, supply 0 (Zero) to \-k.
+.PP
 Finally the  \fB\-d\fR option  enables debugging  output which  is mostly
 usefull for the developer.
 .SS "\s-1PATTERNS\s0"

tablizer.pod

@@ -20,6 +20,7 @@ tablizer - Manipulate tabular output of other programs
       -M, --markdown           Enable markdown table output
       -O, --orgtbl             Enable org-mode table output
       -s, --separator string   Custom field separator
+      -k, --sort-by int        Sort by column (default: 1)
       -v, --version            Print program version
 
 
@@ -78,6 +79,10 @@ The numbering can be suppressed by using the B<-n> option.
 By  default, if  a  B<pattern>  has been  speficied,  matches will  be
 highlighted. You can disable this behavior with the B<-N> option.
 
+Use the  B<-k> option to specify  by which column to  sort the tabular
+data (as in GNU sort(1)). The default sort column is the first one. To
+disable sorting at all, supply 0 (Zero) to -k.
+
 Finally the  B<-d> option  enables debugging  output which  is mostly
 usefull for the developer.