add json output mode (-J) (#87)

README.md

@@ -11,6 +11,23 @@ ignore certain column[s] by regex, name or number. It can output the
 tabular data in a range of formats (see below). There's even an
 interactive filter/selection tool available.
 
+## FEATURES
+
+- supports csv, json or ascii format input from files or stdin
+- split any tabular input data by character or regular expression into columns
+- add headers if input data doesn't contain them (automatically or manually)
+- print tabular data as ascii table, org-mode, markdown, csv, shell-evaluable or yaml format
+- filter rows by regular expression (saves a call to `| grep ...`)
+- filter rows by column filter
+- filters may also be negations eg `-Fname!=cow.*` or `-v`
+- modify cells wih regular expressions
+- reduce columns by specifying which columns to show, with regex support
+- color support
+- sort by any field[s], multiple sort modes are supported
+- shell completion for options
+- regular used options can be put into a config file
+- filter TUI where where you can interactively sort and filter rows
+
 ## Demo
 
 ![demo cast](vhsdemo/demo.gif)
@@ -36,6 +53,9 @@ Operational Flags:
   -R, --regex-transposer </from/to/> Apply /search/replace/ regexp to fields given in -T
   -j, --json                         Read JSON input (must be array of hashes)
   -I, --interactive                  Interactively filter and select rows
+      --auto-headers                 Generate headers if there are none present in input
+      --custom-headers a,b,...       Use custom headers, separated by comma
+
 
 Output Flags (mutually exclusive):
   -X, --extended                     Enable extended output

cfg/config.go

@@ -28,7 +28,7 @@ import (
 )
 
 const (
-	Version  = "v1.5.9"
+	Version  = "v1.5.11"
 	MAXPARTS = 2
 )
 
@@ -93,6 +93,8 @@ type Config struct {
 	UseHighlight   bool
 	Interactive    bool
 	InputJSON      bool
+	AutoHeaders    bool
+	CustomHeaders  []string
 
 	SortMode        string
 	SortDescending  bool
@@ -139,6 +141,7 @@ type Modeflag struct {
 	Y bool
 	A bool
 	C bool
+	J bool
 }
 
 // used for switching printers
@@ -150,6 +153,7 @@ const (
 	Yaml
 	CSV
 	ASCII
+	Json
 )
 
 // various sort types
@@ -288,6 +292,8 @@ func (conf *Config) PrepareModeFlags(flag Modeflag) {
 		conf.OutputMode = Yaml
 	case flag.C:
 		conf.OutputMode = CSV
+	case flag.J:
+		conf.OutputMode = Json
 	default:
 		conf.OutputMode = ASCII
 	}
@@ -413,6 +419,12 @@ func (conf *Config) PreparePattern(patterns []*Pattern) error {
 	return nil
 }
 
+func (conf *Config) PrepareCustomHeaders(custom string) {
+	if len(custom) > 0 {
+		conf.CustomHeaders = strings.Split(custom, ",")
+	}
+}
+
 // Parse config file.  Ignore if the file doesn't exist  but return an
 // error if it exists but fails to read or parse
 func (conf *Config) ParseConfigfile() error {

cmd/root.go

@@ -59,6 +59,7 @@ func Execute() {
 		ShowCompletion string
 		modeflag       cfg.Modeflag
 		sortmode       cfg.Sortmode
+		headers        string
 	)
 
 	var rootCmd = &cobra.Command{
@@ -91,6 +92,7 @@ func Execute() {
 			conf.CheckEnv()
 			conf.PrepareModeFlags(modeflag)
 			conf.PrepareSortFlags(sortmode)
+			conf.PrepareCustomHeaders(headers)
 
 			wrapE(conf.PrepareFilters())
 
@@ -133,10 +135,14 @@ func Execute() {
 		"Transpose the speficied columns (separated by ,)")
 	rootCmd.PersistentFlags().BoolVarP(&conf.Interactive, "interactive", "I", false,
 		"interactive mode")
-	rootCmd.PersistentFlags().StringVarP(&conf.OFS, "ofs", "", "",
+	rootCmd.PersistentFlags().StringVarP(&conf.OFS, "ofs", "o", "",
 		"Output field separator (' ' for ascii table, ',' for CSV)")
 	rootCmd.PersistentFlags().BoolVarP(&conf.InputJSON, "json", "j", false,
 		"JSON input mode")
+	rootCmd.PersistentFlags().BoolVarP(&conf.AutoHeaders, "auto-headers", "g", false,
+		"Generate headers automatically")
+	rootCmd.PersistentFlags().StringVarP(&headers, "custom-headers", "x", "",
+		"Custom headers")
 
 	// sort options
 	rootCmd.PersistentFlags().StringVarP(&conf.SortByColumn, "sort-by", "k", "",
@@ -165,6 +171,8 @@ func Execute() {
 		"Enable shell mode output")
 	rootCmd.PersistentFlags().BoolVarP(&modeflag.Y, "yaml", "Y", false,
 		"Enable yaml output")
+	rootCmd.PersistentFlags().BoolVarP(&modeflag.J, "jsonout", "J", false,
+		"Enable json output")
 	rootCmd.PersistentFlags().BoolVarP(&modeflag.C, "csv", "C", false,
 		"Enable CSV output")
 	rootCmd.PersistentFlags().BoolVarP(&modeflag.A, "ascii", "A", false,

cmd/shortusage.go

@@ -1,16 +1,18 @@
 package cmd
 
 const shortusage = `tablizer [regex,...] [-r file] [flags]
--c col,...   show specified columns                -L  highlight matching lines
--k col,...   sort by specified columns             -j  read JSON input
--F col=reg   filter field with regexp              -v  invert match
--T col,...   transpose specified columns           -n  numberize columns
--R /from/to/ apply replacement to columns in -T    -N  do not use colors
--y col,...   yank columns to clipboard             -H  do not show headers
---ofs char   output field separator                -s  specify field separator
--r file      read input from file                  -z  use fuzzy search
--f file      read config from file                 -I  interactive filter mode
-                                                   -d  debug
--O org -C CSV -M md -X ext -S shell -Y yaml        -D  sort descending order
--m  show manual       --help  show detailed help   -v  show version
--a  sort by age       -i      sort numerically     -t  sort by time`
+-c col,...   show specified columns                  -L  highlight matching lines
+-k col,...   sort by specified columns               -j  read JSON input
+-F col=reg   filter field with regexp                -v  invert match
+-T col,...   transpose specified columns             -n  numberize columns
+-R /from/to/ apply replacement to columns in -T      -N  do not use colors
+-y col,...   yank columns to clipboard               -H  do not show headers
+--ofs char   output field separator                  -s  specify field separator
+-r file      read input from file                    -z  use fuzzy search
+-f file      read config from file                   -I  interactive filter mode
+-x col,...   use custom headers                      -d  debug
+-o char      use char as output separator            -g  auto generate headers
+
+-O org -C CSV -M md -X ext -S shell -Y yaml -J json  -D  sort descending order
+-m  show manual       --help  show detailed help     -v  show version
+-a  sort by age       -i      sort numerically       -t  sort by time`

cmd/tablizer.go

@@ -22,6 +22,8 @@ SYNOPSIS
           -R, --regex-transposer </from/to/> Apply /search/replace/ regexp to fields given in -T
           -j, --json                         Read JSON input (must be array of hashes)
           -I, --interactive                  Interactively filter and select rows
+          -g, --auto-headers                 Generate headers if there are none present in input
+          -x, --custom-headers a,b,...       Use custom headers, separated by comma
 
         Output Flags (mutually exclusive):
           -X, --extended                     Enable extended output
@@ -29,12 +31,13 @@ SYNOPSIS
           -O, --orgtbl                       Enable org-mode table output
           -S, --shell                        Enable shell evaluable output
           -Y, --yaml                         Enable yaml output
+          -J, --jsonout                      Enable JSON output
           -C, --csv                          Enable CSV output
           -A, --ascii                        Default output mode, ascii tabular
           -L, --hightlight-lines             Use alternating background colors for tables
+          -o, --ofs <char>                   Output field separator, used by -A and -C. 
           -y, --yank-columns                 Yank specified columns (separated by ,) to clipboard,
                                              space separated
-              --ofs <char>                   Output field separator, used by -A and -C. 
 
         Sort Mode Flags (mutually exclusive):
           -a, --sort-age                     sort according to age (duration) string
@@ -517,6 +520,8 @@ Operational Flags:
   -R, --regex-transposer </from/to/> Apply /search/replace/ regexp to fields given in -T
   -j, --json                         Read JSON input (must be array of hashes)
   -I, --interactive                  Interactively filter and select rows
+  -g, --auto-headers                 Generate headers if there are none present in input
+  -x, --custom-headers a,b,...       Use custom headers, separated by comma
 
 Output Flags (mutually exclusive):
   -X, --extended                     Enable extended output
@@ -524,12 +529,13 @@ Output Flags (mutually exclusive):
   -O, --orgtbl                       Enable org-mode table output
   -S, --shell                        Enable shell evaluable output
   -Y, --yaml                         Enable yaml output
+  -J, --jsonout                      Enable JSON output
   -C, --csv                          Enable CSV output
   -A, --ascii                        Default output mode, ascii tabular
   -L, --hightlight-lines             Use alternating background colors for tables
+  -o, --ofs <char>                   Output field separator, used by -A and -C. 
   -y, --yank-columns                 Yank specified columns (separated by ,) to clipboard,
                                      space separated
-      --ofs <char>                   Output field separator, used by -A and -C. 
 
 Sort Mode Flags (mutually exclusive):
   -a, --sort-age                     sort according to age (duration) string

lib/parser.go

@@ -66,6 +66,43 @@ func Parse(conf cfg.Config, input io.Reader) (Tabdata, error) {
 	return data, err
 }
 
+/*
+ * Setup headers,  given headers might  be usable headers or  just the
+ * first row, which we use to  determine how many headers to generate,
+ * if enabled.
+ */
+func SetHeaders(conf cfg.Config, headers []string) []string {
+	if !conf.AutoHeaders && len(conf.CustomHeaders) == 0 {
+		return headers
+	}
+
+	if conf.AutoHeaders {
+		heads := make([]string, len(headers))
+		for idx := range headers {
+			heads[idx] = fmt.Sprintf("%d", idx+1)
+		}
+
+		return heads
+	}
+
+	if len(conf.CustomHeaders) == len(headers) {
+		return conf.CustomHeaders
+	}
+
+	// use as much custom ones we have, generate the remainder
+	heads := make([]string, len(headers))
+
+	for idx := range headers {
+		if idx < len(conf.CustomHeaders) {
+			heads[idx] = conf.CustomHeaders[idx]
+		} else {
+			heads[idx] = fmt.Sprintf("%d", idx+1)
+		}
+	}
+
+	return heads
+}
+
 /*
 Parse CSV input.
 */
@@ -87,7 +124,7 @@ func parseCSV(conf cfg.Config, input io.Reader) (Tabdata, error) {
 	}
 
 	if len(records) >= 1 {
-		data.headers = records[0]
+		data.headers = SetHeaders(conf, records[0])
 		data.columns = len(records)
 
 		for _, head := range data.headers {
@@ -98,9 +135,14 @@ func parseCSV(conf cfg.Config, input io.Reader) (Tabdata, error) {
 			}
 		}
 
-		if len(records) > 1 {
-			data.entries = records[1:]
+		if len(records) >= 1 {
+			if conf.AutoHeaders || len(conf.CustomHeaders) > 0 {
+				data.entries = records
+			} else {
+				data.entries = records[1:]
+			}
 		}
+
 	}
 
 	return data, nil
@@ -128,7 +170,9 @@ func parseTabular(conf cfg.Config, input io.Reader) (Tabdata, error) {
 			data.columns = len(parts)
 
 			// process all header fields
-			for _, part := range parts {
+			firstrow := make([]string, len(parts))
+
+			for idx, part := range parts {
 				// register widest header field
 				headerlen := len(part)
 				if headerlen > data.maxwidthHeader {
@@ -136,11 +180,22 @@ func parseTabular(conf cfg.Config, input io.Reader) (Tabdata, error) {
 				}
 
 				// register fields data
-				data.headers = append(data.headers, strings.TrimSpace(part))
+				firstrow[idx] = strings.TrimSpace(part)
 
 				// done
 				hadFirst = true
 			}
+
+			data.headers = SetHeaders(conf, firstrow)
+
+			if conf.AutoHeaders || len(conf.CustomHeaders) > 0 {
+				// we do not use generated headers, consider as row
+				if matchPattern(conf, line) == conf.InvertMatch {
+					continue
+				}
+
+				data.entries = append(data.entries, firstrow)
+			}
 		} else {
 			// data processing
 			if matchPattern(conf, line) == conf.InvertMatch {

lib/parser_test.go

@@ -366,6 +366,56 @@ func TestParserSeparators(t *testing.T) {
 	}
 }
 
+func TestParserSetHeaders(t *testing.T) {
+	row := []string{"c", "b", "c", "d", "e"}
+
+	tests := []struct {
+		name   string
+		custom []string
+		expect []string
+		auto   bool
+	}{
+		{
+			name:   "default",
+			expect: row,
+		},
+		{
+			name:   "auto",
+			expect: strings.Split("1 2 3 4 5", " "),
+			auto:   true,
+		},
+		{
+			name:   "custom-complete",
+			custom: strings.Split("A B C D E", " "),
+			expect: strings.Split("A B C D E", " "),
+		},
+		{
+			name:   "custom-too-short",
+			custom: strings.Split("A B", " "),
+			expect: strings.Split("A B 3 4 5", " "),
+		},
+		{
+			name:   "custom-too-long",
+			custom: strings.Split("A B C D E F G", " "),
+			expect: strings.Split("A B C D E", " "),
+		},
+	}
+
+	for _, testdata := range tests {
+		testname := fmt.Sprintf("parse-%s", testdata.name)
+		t.Run(testname, func(t *testing.T) {
+			conf := cfg.Config{
+				AutoHeaders:   testdata.auto,
+				CustomHeaders: testdata.custom,
+			}
+			headers := SetHeaders(conf, row)
+
+			assert.NotNil(t, headers)
+			assert.EqualValues(t, testdata.expect, headers)
+		})
+	}
+}
+
 func wrapValidateParser(conf cfg.Config, input io.Reader) (Tabdata, error) {
 	data, err := Parse(conf, input)
 

lib/printer.go

@@ -19,6 +19,7 @@ package lib
 
 import (
 	"encoding/csv"
+	"encoding/json"
 	"fmt"
 	"io"
 	"log"
@@ -61,6 +62,8 @@ func printData(writer io.Writer, conf cfg.Config, data *Tabdata) {
 		printShellData(writer, data)
 	case cfg.Yaml:
 		printYamlData(writer, data)
+	case cfg.Json:
+		printJsonData(writer, data)
 	case cfg.CSV:
 		printCSVData(writer, conf, data)
 	default:
@@ -291,6 +294,35 @@ func printShellData(writer io.Writer, data *Tabdata) {
 	output(writer, out)
 }
 
+func printJsonData(writer io.Writer, data *Tabdata) {
+	objlist := make([]map[string]any, len(data.entries))
+
+	if len(data.entries) > 0 {
+		for i, entry := range data.entries {
+			obj := make(map[string]any, len(entry))
+
+			for idx, value := range entry {
+				num, err := strconv.Atoi(value)
+				if err == nil {
+					obj[data.headers[idx]] = num
+				} else {
+					obj[data.headers[idx]] = value
+				}
+			}
+
+			objlist[i] = obj
+		}
+	}
+
+	jsonstr, err := json.MarshalIndent(&objlist, "", "  ")
+
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	output(writer, string(jsonstr))
+}
+
 func printYamlData(writer io.Writer, data *Tabdata) {
 	type Data struct {
 		Entries []map[string]interface{} `yaml:"entries"`

lib/printer_test.go

@@ -125,6 +125,31 @@ ceta,33d12h,9,06/Jan/2008 15:04:05 -0700`,
 NAME="beta" DURATION="1d10h5m1s" COUNT="33" WHEN="3/1/2014"
 NAME="alpha" DURATION="4h35m" COUNT="170" WHEN="2013-Feb-03"
 NAME="ceta" DURATION="33d12h" COUNT="9" WHEN="06/Jan/2008 15:04:05 -0700"`,
+	},
+	{
+		name:      "json",
+		mode:      cfg.Json,
+		numberize: false,
+		expect: `[
+  {
+    "COUNT": 33,
+    "DURATION": "1d10h5m1s",
+    "NAME": "beta",
+    "WHEN": "3/1/2014"
+  },
+  {
+    "COUNT": 170,
+    "DURATION": "4h35m",
+    "NAME": "alpha",
+    "WHEN": "2013-Feb-03"
+  },
+  {
+    "COUNT": 9,
+    "DURATION": "33d12h",
+    "NAME": "ceta",
+    "WHEN": "06/Jan/2008 15:04:05 -0700"
+  }
+]`,
 	},
 	{
 		name:      "yaml",

tablizer.1

@@ -133,7 +133,7 @@
 .\" ========================================================================
 .\"
 .IX Title "TABLIZER 1"
-.TH TABLIZER 1 "2025-10-09" "1" "User Commands"
+.TH TABLIZER 1 "2025-10-13" "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
@@ -160,6 +160,8 @@ tablizer \- Manipulate tabular output of other programs
 \&      \-R, \-\-regex\-transposer </from/to/> Apply /search/replace/ regexp to fields given in \-T
 \&      \-j, \-\-json                         Read JSON input (must be array of hashes)
 \&      \-I, \-\-interactive                  Interactively filter and select rows
+\&      \-g, \-\-auto\-headers                 Generate headers if there are none present in input
+\&      \-x, \-\-custom\-headers a,b,...       Use custom headers, separated by comma
 \&
 \&    Output Flags (mutually exclusive):
 \&      \-X, \-\-extended                     Enable extended output
@@ -167,12 +169,13 @@ tablizer \- Manipulate tabular output of other programs
 \&      \-O, \-\-orgtbl                       Enable org\-mode table output
 \&      \-S, \-\-shell                        Enable shell evaluable output
 \&      \-Y, \-\-yaml                         Enable yaml output
+\&      \-J, \-\-jsonout                      Enable JSON output
 \&      \-C, \-\-csv                          Enable CSV output
 \&      \-A, \-\-ascii                        Default output mode, ascii tabular
 \&      \-L, \-\-hightlight\-lines             Use alternating background colors for tables
+\&      \-o, \-\-ofs <char>                   Output field separator, used by \-A and \-C. 
 \&      \-y, \-\-yank\-columns                 Yank specified columns (separated by ,) to clipboard,
 \&                                         space separated
-\&          \-\-ofs <char>                   Output field separator, used by \-A and \-C. 
 \&
 \&    Sort Mode Flags (mutually exclusive):
 \&      \-a, \-\-sort\-age                     sort according to age (duration) string

tablizer.pod

@@ -21,6 +21,8 @@ tablizer - Manipulate tabular output of other programs
       -R, --regex-transposer </from/to/> Apply /search/replace/ regexp to fields given in -T
       -j, --json                         Read JSON input (must be array of hashes)
       -I, --interactive                  Interactively filter and select rows
+      -g, --auto-headers                 Generate headers if there are none present in input
+      -x, --custom-headers a,b,...       Use custom headers, separated by comma
 
     Output Flags (mutually exclusive):
       -X, --extended                     Enable extended output
@@ -28,12 +30,13 @@ tablizer - Manipulate tabular output of other programs
       -O, --orgtbl                       Enable org-mode table output
       -S, --shell                        Enable shell evaluable output
       -Y, --yaml                         Enable yaml output
+      -J, --jsonout                      Enable JSON output
       -C, --csv                          Enable CSV output
       -A, --ascii                        Default output mode, ascii tabular
       -L, --hightlight-lines             Use alternating background colors for tables
+      -o, --ofs <char>                   Output field separator, used by -A and -C. 
       -y, --yank-columns                 Yank specified columns (separated by ,) to clipboard,
                                          space separated
-          --ofs <char>                   Output field separator, used by -A and -C. 
 
     Sort Mode Flags (mutually exclusive):
       -a, --sort-age                     sort according to age (duration) string