Precompile regular expressions

Fixes #20

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>

bot.go

@@ -9,6 +9,8 @@ import (
 	"strings"
 )
 
+var botFromSiteRegexp = regexp.MustCompile("http://.+\\.\\w+")
+
 // Get the name of the bot from the website that may be in the given comment. If
 // there is no website in the comment, then an empty string is returned.
 func getFromSite(comment []string) string {
@@ -23,8 +25,7 @@ func getFromSite(comment []string) string {
 	}
 
 	// Pick the site.
-	re := regexp.MustCompile("http://.+\\.\\w+")
-	results := re.FindStringSubmatch(comment[idx])
+	results := botFromSiteRegexp.FindStringSubmatch(comment[idx])
 	if len(results) == 1 {
 		// If it's a simple comment, just return the name of the site.
 		if idx == 0 {

browser.go

@@ -9,6 +9,8 @@ import (
 	"strings"
 )
 
+var ie11Regexp = regexp.MustCompile("^rv:(.+)$")
+
 // A struct containing all the information that we might be
 // interested from the browser.
 type Browser struct {
@@ -75,9 +77,8 @@ func (p *UserAgent) detectBrowser(sections []section) {
 				// This is the new user agent from Internet Explorer 11.
 				p.browser.Engine = "Trident"
 				p.browser.Name = "Internet Explorer"
-				reg, _ := regexp.Compile("^rv:(.+)$")
 				for _, c := range sections[0].comment {
-					version := reg.FindStringSubmatch(c)
+					version := ie11Regexp.FindStringSubmatch(c)
 					if len(version) > 0 {
 						p.browser.Version = version[1]
 						return