New Feature: Extra arguments

Fixes #51. Teach Pistol to accept extra arguments to be passed to the
commands defined in the config. If the matched line in the config
doesn't use `%pistol-extra[0-9]%` the argument is discarded.

Update documentation and add tests.

Makefile

@@ -42,6 +42,17 @@ test: pistol
 	@echo exit code \(issue '#'52\):
 	@echo -------------------
 	@./tests/exit-code.sh
+	@tput sgr0
+	@echo -------------------
+	@echo ./tests/VERSION.bz2 should appear along with license of bz2
+	@echo -------------------
+	@./pistol --config tests/config tests/VERSION.bz2 -v -L
+	@tput sgr0
+	@echo -------------------
+	@echo ./tests/renovate.json5.bz2 should appear without a license of bz2
+	@echo or verbosity, although the arguments are passed to pistol
+	@echo -------------------
+	@./pistol --config tests/config tests/renovate.json5.bz2 -v -L
 
 deps:
 	go get github.com/c4milo/github-release

README.adoc

@@ -135,7 +135,7 @@ https://github.com/doronbehar/pistol/issues/6[#6] for more details.]
 
 ....
 $ pistol --help
-Usage: pistol OPTIONS [<file> ...]
+Usage: pistol OPTIONS <file> [<extras> ...]
 
 OPTIONS
 
@@ -146,6 +146,7 @@ OPTIONS
 ARGUMENTS
 
 file                        the file to preview
+extras                      extra arguments passed to the command
 ....
 
 === Integrations
@@ -329,6 +330,46 @@ More over, with `sh:` you can use shell pipes:
 fpath .*.md$ sh: bat --paging=never --color=always %pistol-filename% | head -8
 ----
 
+==== Passing arbitrary extra arguments to commands
+
+Pistol is capable of passing extra arguments to commands if the config says so.
+The arguments `%pistol-extra0%`, `%pistol-extra1%` and so on, are substituted
+by the extra arguments given to `pistol`, if these present in invokation and if
+they are present in the config. Example usage:
+
+With this config:
+
+....
+fpath /problematic-bz2/.*.bz2 bzip2 %pistol-filename% %pistol-extra0%
+fpath /working-bz2/.*.bz2     bzip2 %pistol-filename%
+....
+
+Running:
+
+....
+pistol /problematic-bz2/example.bz2 --test
+....
+
+Will run bzip2 while testing the integrity of the compressed file. However,
+running: 
+
+....
+pistol /working-bz2/example.bz2 --test
+....
+
+Will not pass the `--test` argument to bzip, due to `%pistol-extra0` not
+present in the config for the files at `/working-bz2`. This feature is mainly
+present for usage with https://github.com/gokcehan/lf[Lf] and
+https://ranger.github.io/[Ranger] which can pass width height and x, y
+coordinates for image previews.
+
+Here's an example usage for image previews that works with Lf:
+footnote:[`pv` script refers to https://github.com/neeshy/lfimg/blob/e9154721514a1384a89f2713092c15dc77992f37/pv[this script].]
+
+....
+image/.* pv %pistol-filename% %pistol-extra0% %pistol-extra1% %pistol-extra2% %pistol-extra3%
+....
+
 === Environmental Variables
 
 Pistol’s internal previewer for text files includes syntax highlighting

cmd/pistol/main.go

@@ -23,7 +23,8 @@ func main() {
 	cmd := cmdline.New()
 	cmd.AddOption("c", "config", "config file", fmt.Sprintf("configuration file to use (defaults to %s/pistol/pistol.conf)", xdg.ConfigHome))
 	cmd.AddFlag("V", "version", "Print version date and exit")
-	cmd.AddTrailingArguments("file", "the file to preview")
+	cmd.AddArgument("file", "the file to preview")
+	cmd.AddTrailingArguments("extras", "extra arguments passed to the command")
 	cmd.Parse(os.Args)
 
 	if cmd.IsOptionSet("version") {
@@ -42,13 +43,15 @@ func main() {
 		}
 	}
 	configPath := cmd.OptionValue("config")
+	var extras []string
+	extras = cmd.TrailingArgumentsValues("extras")
 
 	// handle file argument with configuration
-	if len(cmd.TrailingArgumentsValues("file")) == 0 {
+	if len(cmd.ArgumentValue("file")) == 0 {
 		log.Fatalf("no arguments!")
 		os.Exit(1)
 	}
-	previewer, err := pistol.NewPreviewer(cmd.TrailingArgumentsValues("file")[0], configPath)
+	previewer, err := pistol.NewPreviewer(cmd.ArgumentValue("file"), configPath, extras)
 	if err != nil {
 		log.Fatal(err)
 		os.Exit(2)

previewer.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"os/exec"
 	// "fmt"
+	"strconv"
 	"strings"
 	"regexp"
 	"path/filepath"
@@ -21,6 +22,8 @@ import (
 type Previewer struct {
 	// The file to be previewed
 	FilePath string
+	// Extra arguments passed to pistol
+	Extras []string
 	// The mime type detected
 	MimeType string
 	// The command that will be used to print the file. If empty, internal
@@ -50,7 +53,7 @@ type Previewer struct {
 //
 // Many mime types are handled internally by Pistol, see table here:
 // https://github.com/doronbehar/pistol#introduction
-func NewPreviewer(filePath, configPath string) (Previewer, error) {
+func NewPreviewer(filePath, configPath string, extras []string) (Previewer, error) {
 	verbose := os.Getenv("PISTOL_DEBUG")
 	if verbose != "" {
 		log.SetLevel(log.InfoLevel)
@@ -72,6 +75,7 @@ func NewPreviewer(filePath, configPath string) (Previewer, error) {
 	p.MimeType = mimetype
 	log.Infof("detected mimetype is %s", p.MimeType)
 	p.FilePath = filePath
+	p.Extras = extras
 	// If configuration file doesn't exist, we don't try to read it
 	if configPath == "" {
 		log.Warnf("configuration file was not supplied")
@@ -155,9 +159,24 @@ func (p *Previewer) Write(w io.Writer) (error) {
 		}
 		var cmd *exec.Cmd
 		var argsOut []string
+
+		re := regexp.MustCompile(`%pistol-extra([0-9]+)%`)
+
 		for _, arg := range p.Args {
-			argsOut = append(argsOut, strings.ReplaceAll(arg, "%pistol-filename%", replStr))
+			if(re.MatchString(arg)) {
+				auxStr := re.ReplaceAllString(arg, "$1")
+				auxInt, err := strconv.Atoi(auxStr);
+				if (err == nil && len(p.Extras) > auxInt) {
+					arg = re.ReplaceAllString(arg, p.Extras[auxInt])
+				} else {
+					continue
+				}
+			} else {
+				arg = strings.ReplaceAll(arg, "%pistol-filename%", replStr)
+			}
+			argsOut = append(argsOut, arg)
 		}
+
 		if p.Command == "sh:" {
 			log.Infof("previewer's command is (shell interpreted): %#v\n", argsOut)
 			cmd = exec.Command("sh", "-c", strings.Join(argsOut, " "))

tests/config

@@ -6,6 +6,10 @@ fpath .*/tests/fpath-with-sh$ sh: bat --map-syntax :Markdown --paging=never --st
 text/html elinks -dump -dump-color-mode 1 %pistol-filename%
 # detects: mimetype, sh: yes
 text/plain sh: bat --map-syntax :Markdown --paging=never --style=numbers --color=always %pistol-filename% | head -1
+# Test extra arguments
+fpath .*/tests/VERSION.bz2$ bzcat %pistol-extra0% %pistol-extra1% %pistol-filename%
+# Test extra arguments
+fpath .*/tests/renovate.json5.bz2$ bzcat %pistol-filename%
 # Test exit code is non-zero in case a command does not exist:
 application/x-bzip2 not-a-real-command %pistol-filename%
 # Test exit code is non-zero in case a command starts but fails to finish

tests/exit-code.sh

@@ -6,16 +6,16 @@ if ./pistol --config tests/config tests/34.json.bz2; then
 	exit 1
 else
 	tput setaf 2
-	echo "exit code was not zero"
+	echo "exit code was not zero when testing a non real command"
 fi
 
 if ./pistol --config tests/config tests; then
 	tput setaf 1
-	echo "exit code was not non-zero when testing a real command with invalid arguments for it"
+	echo "exit code was not non-zero when testing a real command with invalid arguments"
 	exit 1
 else
 	tput setaf 2
-	echo "exit code was not zero"
+	echo "exit code was not zero when testing a real command with invalid arguments"
 fi
 tput sgr0
 exit 0