colorize-output using regexes, refactor line colorization (#49)

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
@@ -28,7 +28,7 @@ import (
 )
 
 const (
-	Version  = "v1.5.12"
+	Version  = "v1.6.0"
 	MAXPARTS = 2
 )
 
@@ -102,15 +102,15 @@ 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
-	 see https://github.com/gookit/color.
-	*/
 	ColorStyle        color.Style
 	HighlightStyle    color.Style
 	NoHighlightStyle  color.Style
@@ -357,6 +357,23 @@ 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.