Golang: Find String (grep) Script

Here's a script that does find string or multiple strings in all files in a dir.

// -*- coding: utf-8 -*-
// File name: xah_find.go
// Description: find strings in a dir. Can be a list of strings
// website: http://xahlee.info/golang/goland_find_string.html
// version 2020-05-24 2022-07-24 2022-07-29 2022-08-07

package main

import (
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	"time"
	"unicode/utf8"
)

// inDir is dir to start. must be full path
var inDir = "c:/Users/xah/web/"

// fnameRegex. only these are searched
const fnameRegex = `\.html$`

// dir name, not full path. and exact equal, not regex
var dirsToSkip = []string{
	".git",
	"REC-SVG11-20110816",
	"clojure-doc-1.8",
	"emacs_manual",
	"js_es2011",
	"js_es2015",
	"node_api",
}

// fileList if not empty, only these are processed. Each element is a full path
var fileList = []string{}

// list of string to search
// each item is intepreted as regex
// use regexp.QuoteMeta to quote them if want plain text
var findList = []string{

	regexp.QuoteMeta(`haskell`),
}

// number of chars (actually bytes) to show before the found string
const charsBefore = 100
const charsAfter = 100

const fileSep = "━━━━━filesepM6bcX━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"

const occurSep = "─────occurSep5h4DP──────────────────────────────────────────"

const occurBracketL = '⦋'
const occurBracketR = '⦌'

const posBracketL = '⁅'
const posBracketR = '⁆'

const fileBracketL = '❬'
const fileBracketR = '❭'

var bigRegexStr = strings.Join(findList, "|")

var rgx = regexp.MustCompile(bigRegexStr)

func printSliceStr(sliceX []string) error {
	for k, v := range sliceX {
		fmt.Printf("%v %v\n", k, v)
	}
	return nil
}

// scriptPath returns the current running script path
// version 2018-10-07
func scriptPath() string {
	name, errPath := os.Executable()
	if errPath != nil {
		panic(errPath)
	}
	return name
}

func max(x int, y int) int {
	if x > y {
		return x
	} else {
		return y
	}
}
func min(x int, y int) int {
	if x > y {
		return y
	} else {
		return x
	}
}

// stringMatchAny return true if x equals any of y
func stringMatchAny(x string, y []string) bool {
	for _, v := range y {
		if x == v {
			return true
		}
	}
	return false
}

func doFile(path string) error {
	var textBytes, er = os.ReadFile(path)
	if er != nil {
		panic(er)
	}

	var indexes = rgx.FindAllIndex(textBytes, -1)

	var bytesLength = len(textBytes)
	if len(indexes) != 0 {
		for _, k := range indexes {
			var foundStart = k[0]
			var foundEnd = k[1]
			var showStart = max(foundStart-charsBefore, 0)
			for !utf8.RuneStart(textBytes[showStart]) {
				showStart = max(showStart-1, 0)
			}

			var showEnd = min(foundEnd+charsAfter, bytesLength-1)
			for !utf8.RuneStart(textBytes[showEnd]) {
				showEnd = min(showEnd-1, bytesLength)
			}

			// 			fmt.Printf("%s〖%s〗%s\n", textBytes[showStart:foundStart],
			fmt.Printf("%c%d%c %s%c%s%c%s\n",
				posBracketL,
				utf8.RuneCount(textBytes[0:foundStart+1]),
				posBracketR,
				textBytes[showStart:foundStart],
				occurBracketL,
				textBytes[foundStart:foundEnd],
				occurBracketR,
				textBytes[foundEnd:showEnd])
			fmt.Println(occurSep)
		}
		fmt.Printf("%v %c%v%c\n", len(indexes), fileBracketL, path, fileBracketR)
		fmt.Println(fileSep, "\n")
	}
	return nil
}

var f_walkfunc = func(xpath string, xinfo fs.DirEntry, xerr error) error {
	// first thing to do, check error. and decide what to do about it
	if xerr != nil {
		fmt.Printf("error [%v] at a path [%q]\n", xerr, xpath)
		return xerr
	}
	if xinfo.IsDir() {
		if stringMatchAny(filepath.Base(xpath), dirsToSkip) {
			return filepath.SkipDir
		}
	} else {
		var x, err = regexp.MatchString(fnameRegex, filepath.Base(xpath))
		if err != nil {
			panic("stupid MatchString error 59767")
		}
		if x {
			doFile(xpath)
		}
	}
	return nil
}

func main() {

	fmt.Println("-*- coding: utf-8; mode: xah-find-output -*-")
	fmt.Printf("%v\n", time.Now())
	fmt.Printf("Script: %v\n", filepath.Base(scriptPath()))
	fmt.Printf("in dir: %v\n", inDir)
	fmt.Printf("file regex filter: %v\n", fnameRegex)
	fmt.Printf("fileList:\n")
	printSliceStr(fileList)
	fmt.Printf("findList:\n")
	printSliceStr(findList)
	fmt.Println()
	fmt.Println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n")

	if len(fileList) >= 1 {
		for _, v := range fileList {
			doFile(v)
		}
	} else {
		err := filepath.WalkDir(inDir, f_walkfunc)
		if err != nil {
			fmt.Printf("error walking the path %q: %v\n", inDir, err)
		}
	}

	fmt.Println("\nDone.")
}

Emacs Integration

This script is integrated with emacs.

If you use emacs:

1. Install Emacs: xah-find.el, Find Replace in Pure Elisp
2. bookmark the golang script so you can easily open it when you need find replace. 〔see Emacs: Bookmark〕
3. Open the golang script, change input dir and find replace strings.
4. Alt+x xah-run-current-file to run the script. 〔see Emacs: Run Current File〕
5. In output, Alt+x xah-find-output-mode, to highlight result, and press enter on highlighted find/replace string text or file path to open the file.

If you are using Xah Fly Keys, many of the command above is already there. You still need to install xah-find.el for coloring the output.

〔see Emacs: Xah Fly Keys 📦〕