add output colorization support using regexes

cfg/config.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2022-2025 Thomas von Dein
+Copyright © 2022-2026 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
@@ -102,10 +102,14 @@ type Config struct {
 	SortByColumn    string // 1,2
 	UseSortByColumn []int  // []int{1,2}
 
-	TransposeColumns    string       // 1,2
-	UseTransposeColumns []int        // []int{1,2}
-	Transposers         []string     // []string{"/ /-/", "/foo/bar/"}
-	UseTransposers      []Transposer // {Search: re, Replace: string}
+	TransposeColumns    string // 1,2
+	UseTransposeColumns []int  // []int{1,2}
+
+	Transposers    []string     // []string{"/ /-/", "/foo/bar/"}
+	UseTransposers []Transposer // {Search: re, Replace: string}
+
+	Colorizers    []string     // []string{"/ /-/", "/foo/fg[:bg]/"}
+	UseColorizers []Transposer // {Search: re, Replace: color}
 
 	/*
 	 FIXME: make configurable somehow, config file or ENV
@@ -357,6 +361,23 @@ func (conf *Config) PrepareTransposers() error {
 	return nil
 }
 
+func (conf *Config) PrepareColorizers() error {
+	for _, colorizer := range conf.Colorizers {
+		parts := strings.Split(colorizer, string(colorizer[0]))
+		if len(parts) != 4 {
+			return fmt.Errorf("colorizer function must have the format /regexp/foreground-color[:background-color]/")
+		}
+
+		conf.UseColorizers = append(conf.UseColorizers,
+			Transposer{
+				Search:  *regexp.MustCompile(parts[1]),
+				Replace: parts[2]},
+		)
+	}
+
+	return nil
+}
+
 func (conf *Config) CheckEnv() {
 	// check for environment vars, command line flags have precedence,
 	// NO_COLOR is being checked by the color module itself.

cmd/root.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2022-2025 Thomas von Dein
+Copyright © 2022-2026 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
@@ -95,6 +95,7 @@ func Execute() {
 			conf.PrepareCustomHeaders(headers)
 
 			wrapE(conf.PrepareFilters())
+			wrapE(conf.PrepareColorizers())
 
 			conf.DetermineColormode()
 			conf.ApplyDefaults()
@@ -191,6 +192,8 @@ func Execute() {
 		"filter", "F", nil, "Filter by field (field=regexp || field!=regexp)")
 	rootCmd.PersistentFlags().StringArrayVarP(&conf.Transposers,
 		"regex-transposer", "R", nil, "apply /search/replace/ regexp to fields given in -T")
+	rootCmd.PersistentFlags().StringArrayVarP(&conf.Colorizers,
+		"regex-colorizer", "K", nil, "apply /search/color[:background]/ to the whole output")
 
 	// input
 	rootCmd.PersistentFlags().StringVarP(&conf.InputFile, "read-file", "r", "",

cmd/shortusage.go

@@ -13,6 +13,7 @@ const shortusage = `tablizer [regex,...] [-r file] [flags]
 -x col,...   use custom headers                      -d  debug
 -o char      use char as output separator            -g  auto generate headers
 
+-K /pattern/foreground[:background]/ colorize pattern of output
 -O org  -C CSV  -M md  -X ext  -S shell  -Y yaml  -J json  -P template
 -a sort by age   -i sort numerically   -t sort by time   -D sort descending order
 -m show manual   -v  show version      --help  show detailed help`

lib/filter.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2022-2025 Thomas von Dein
+Copyright © 2022-2026 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
@@ -22,8 +22,8 @@ import (
 	"io"
 	"strings"
 
-	"github.com/lithammer/fuzzysearch/fuzzy"
 	"codeberg.org/scip/tablizer/cfg"
+	"github.com/lithammer/fuzzysearch/fuzzy"
 )
 
 /*

lib/helpers.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2022 Thomas von Dein
+Copyright © 2022-2026 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
@@ -26,8 +26,8 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/gookit/color"
 	"codeberg.org/scip/tablizer/cfg"
+	"github.com/gookit/color"
 )
 
 func findindex(s []int, e int) (int, bool) {

lib/printer.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2022-2025 Thomas von Dein
+Copyright © 2022-2026 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
@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"os"
 	"strconv"
 	"strings"
 	"text/template"
@@ -75,8 +76,8 @@ func printData(writer io.Writer, conf cfg.Config, data *Tabdata) {
 	}
 }
 
-func output(writer io.Writer, str string) {
-	_, err := fmt.Fprint(writer, str)
+func output(writer io.Writer, conf cfg.Config, str string) {
+	_, err := fmt.Fprint(writer, colorizeOutput(conf, str))
 	if err != nil {
 		log.Fatalf("failed to print output: %s", err)
 	}
@@ -138,7 +139,7 @@ func printOrgmodeData(writer io.Writer, conf cfg.Config, data *Tabdata) {
 		log.Fatalf("Failed to render table: %s", err)
 	}
 
-	output(writer, color.Sprint(colorizeData(conf, tableString.String())))
+	output(writer, conf, color.Sprint(colorizeData(conf, tableString.String())))
 }
 
 /*
@@ -197,7 +198,7 @@ func printMarkdownData(writer io.Writer, conf cfg.Config, data *Tabdata) {
 		log.Fatalf("Failed to render table: %s", err)
 	}
 
-	output(writer, color.Sprint(colorizeData(conf, tableString.String())))
+	output(writer, conf, color.Sprint(colorizeData(conf, tableString.String())))
 }
 
 /*
@@ -254,7 +255,7 @@ func printASCIIData(writer io.Writer, conf cfg.Config, data *Tabdata) {
 		log.Fatalf("Failed to render table: %s", err)
 	}
 
-	output(writer, color.Sprint(colorizeData(conf, tableString.String())))
+	output(writer, conf, color.Sprint(colorizeData(conf, tableString.String())))
 }
 
 /*
@@ -275,7 +276,7 @@ func printExtendedData(writer io.Writer, conf cfg.Config, data *Tabdata) {
 		}
 	}
 
-	output(writer, colorizeData(conf, out))
+	output(writer, conf, colorizeData(conf, out))
 }
 
 /*
@@ -298,7 +299,7 @@ func printShellData(writer io.Writer, data *Tabdata) {
 	}
 
 	// no colorization here
-	output(writer, out)
+	output(writer, cfg.Config{}, out)
 }
 
 func printJsonData(writer io.Writer, data *Tabdata) {
@@ -327,7 +328,7 @@ func printJsonData(writer io.Writer, data *Tabdata) {
 		log.Fatal(err)
 	}
 
-	output(writer, string(jsonstr))
+	output(writer, cfg.Config{}, string(jsonstr))
 }
 
 func printYamlData(writer io.Writer, data *Tabdata) {
@@ -364,7 +365,7 @@ func printYamlData(writer io.Writer, data *Tabdata) {
 		log.Fatal(err)
 	}
 
-	output(writer, string(yamlstr))
+	output(writer, cfg.Config{}, string(yamlstr))
 }
 
 func printCSVData(writer io.Writer, conf cfg.Config, data *Tabdata) {
@@ -414,3 +415,23 @@ func printTemplateData(writer io.Writer, conf cfg.Config, data *Tabdata) {
 		log.Fatalf("failed to print output: %s", err)
 	}
 }
+
+func colorizeOutput(conf cfg.Config, input string) string {
+	if len(conf.UseColorizers) > 0 && !conf.NoColor && color.IsConsole(os.Stdout) {
+		for _, colorizer := range conf.UseColorizers {
+			// colorize matching parts of the whole output with given color, if the terminal supports it
+			// color may contain fg:bg or just fg. Color definitions see https://github.com/gookit/color
+			input = colorizer.Search.ReplaceAllStringFunc(input, func(in string) string {
+				col := colorizer.Replace
+				if strings.Contains(col, ":") {
+					parts := strings.Split(col, ":")
+					return color.Sprintf(fmt.Sprintf("<fg=%s;bg=%s>%s</>", parts[0], parts[1], in))
+				}
+
+				return color.Sprintf(fmt.Sprintf("<fg=%s>%s</>", col, in))
+			})
+		}
+	}
+
+	return input
+}

t/testtable6.csv

@@ -0,0 +1,5 @@
+Date,Account Number,Subject,Amount
+20250101,968723487,Dogs Medication Invoice 9919292,-450.00
+20250103,172747812,Tax return tax id HHD813D/12564H,+912.14
+20250105,987122711,Car repair order 020123,-299.45
+20250108,731217273,Rent - 12234 Sunset Blvd,-2960.00

tablizer.pod

@@ -19,6 +19,7 @@ tablizer - Manipulate tabular output of other programs
       -F, --filter <field[!]=reg>        Filter given field with regex, can be used multiple times
       -T, --transpose-columns string     Transpose the speficied columns (separated by ,)
       -R, --regex-transposer </from/to/> Apply /search/replace/ regexp to fields given in -T
+      -K  --regex-colorizer /from/color/ colorize pattern of output (color: fg[:bg])
       -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
@@ -514,9 +515,20 @@ black, blue,  cyan, darkGray, default, green,  lightBlue, lightCyan,
 lightGreen,   lightMagenta,   lightRed,   lightWhite,   lightYellow,
 magenta, red, white, yellow
 
-The Variables B<FG> and B<BG> are being used to highlight matches. The
-other *FG and *BG variables are for colored table output (enabled with
-the C<-L> parameter).
+but you may also use HTML color codes without the hash sign.
+
+The Variables  B<FG> and  B<BG> are being  used to  highlight matching
+rows. The  other *FG and  *BG variables  are for colored  table output
+(enabled with the C<-L> parameter).
+
+You can also use the option C<-K> to colorize particular patterns, not
+whole lines. The option can be given multiple times and expects the
+following parameter:
+
+    -K '/regex/foreground[:background]/
+
+that is, background color is optional. This colorization will applied
+on top of any previous colorizations, if any.
 
 Colorization can be turned off completely either by setting the
 parameter C<-N> or the environment variable B<NO_COLOR> to a true value.