Merge pull request tomnomnom#34 from omerxx/master

Adding custom engines

README.md

@@ -26,7 +26,7 @@ becomes simply:
 The pattern definitions are stored in `~/.gf` as little JSON files that can be kept under version control:
 
 ```
-▶ cat ~/.gf/php-sources.json 
+▶ cat ~/.gf/php-sources.json
 {
     "flags": "-HnrE",
     "pattern": "(\\$_(POST|GET|COOKIE|REQUEST|SERVER|FILES)|php://(input|stdin))"
@@ -84,6 +84,24 @@ source ~/path/to/gf-completion.zsh
 Note: if you're using oh-my-zsh or similar you may find that `gf` is an alias for `git fetch`. You can either
 alias the gf binary to something else, or `unalias gf` to remove the `git fetch` alias.
 
+### Using custom engines
+
+There are some amazing code searching engines out there that can be a better replacement for grep.
+A good example is [the silver searcher](https://github.com/ggreer/the_silver_searcher).
+It's faster (like **way faster**) and presents the results in a more visually digestible manner.
+In order to utilize a different engine, add `engine: <other tool>` to the relevant pattern file:
+```bash
+# Using the silver searcher instead of grep for the aws-keys pattern:
+# 1. Adding "ag" engine
+# 2. Removing the E flag which is irrelevant for ag
+{
+  "engine": "ag",
+  "flags": "-Hanr",
+  "pattern": "([^A-Z0-9]|^)(AKIA|A3T|AGPA|AIDA|AROA|AIPA|ANPA|ANVA|ASIA)[A-Z0-9]{12,}"
+}
+```
+* Note: Different engines use different flags, so in the example above, the flag `E` has to be removed from the `aws-keys.json` file in order for ag to successfully run.
+
 
 ## Install
 

main.go

@@ -16,6 +16,7 @@ type pattern struct {
 	Flags    string   `json:"flags,omitempty"`
 	Pattern  string   `json:"pattern,omitempty"`
 	Patterns []string `json:"patterns,omitempty"`
+	Engine   string   `json:"engine,omitempty"`
 }
 
 func main() {
@@ -93,15 +94,20 @@ func main() {
 	}
 
 	if dumpMode {
-		fmt.Printf( "grep --color %v %q %v\n", pat.Flags, pat.Pattern, files )
+		fmt.Printf("grep --color %v %q %v\n", pat.Flags, pat.Pattern, files)
 		//fmt.Println( "grep --color", pat.Flags, pat.Pattern, files)
 
 	} else {
 		var cmd *exec.Cmd
+		operator := "grep"
+		if pat.Engine != "" {
+			operator = pat.Engine
+		}
+
 		if stdinIsPipe() {
-			cmd = exec.Command("grep", "--color", pat.Flags, pat.Pattern)
+			cmd = exec.Command(operator, "--color", pat.Flags, pat.Pattern)
 		} else {
-			cmd = exec.Command("grep", "--color", pat.Flags, pat.Pattern, files)
+			cmd = exec.Command(operator, "--color", pat.Flags, pat.Pattern, files)
 		}
 		cmd.Stdin = os.Stdin
 		cmd.Stdout = os.Stdout