From d0fbe716d955f90aad022bb0a1a923cbd0eac551 Mon Sep 17 00:00:00 2001
From: Dan Buch <daniel.buch@gmail.com>
Date: Sat, 10 Nov 2012 20:27:23 -0500
Subject: [PATCH] Messing around with I/O streams and regexes

---
 gotime/Makefile                               |  4 ++
 .../junkdrawer/greppish/main.go               | 51 +++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 gotime/src/meatballhat.com/junkdrawer/greppish/main.go

diff --git a/gotime/Makefile b/gotime/Makefile
index d47f342..a3ea54b 100644
--- a/gotime/Makefile
+++ b/gotime/Makefile
@@ -4,6 +4,10 @@ PACKAGES := $(foreach pkg,\
 		$(shell ls src/meatballhat.com/gotour-artifacts),\
 		$(patsubst %,meatballhat.com/gotour-artifacts/%,$(pkg))\
 	)
+PACKAGES += $(foreach pkg,\
+		$(shell ls src/meatballhat.com/junkdrawer),\
+		$(patsubst %,meatballhat.com/junkdrawer/%,$(pkg))\
+	)
 PACKAGES += meatballhat.com/amqpfun-runner
 
 test: build
diff --git a/gotime/src/meatballhat.com/junkdrawer/greppish/main.go b/gotime/src/meatballhat.com/junkdrawer/greppish/main.go
new file mode 100644
index 0000000..da641fa
--- /dev/null
+++ b/gotime/src/meatballhat.com/junkdrawer/greppish/main.go
@@ -0,0 +1,51 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"regexp"
+)
+
+const USAGE = `Usage: greppish <regex> [filename]
+
+Prints lines matching <regex> in [filename] or standard input.`
+
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Println(USAGE)
+		os.Exit(1)
+	}
+
+	regMatch, err := regexp.Compile(os.Args[1])
+	if err != nil {
+		log.Fatal("Problem compiling regex: ", err)
+	}
+
+	inbuf := bufio.NewReader(os.Stdin)
+
+	if len(os.Args) > 2 {
+		infile, err := os.Open(os.Args[2])
+		if err != nil {
+			log.Fatal("Problem opening input file: ", err)
+		}
+		inbuf = bufio.NewReader(infile)
+	}
+
+	var line string
+
+	for {
+		line, err = inbuf.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				os.Exit(0)
+			}
+			log.Fatal("Problem reading input: ", err)
+		}
+		if regMatch.MatchString(line) {
+			fmt.Printf(line)
+		}
+	}
+}