From 2ecb2acf6b73d285bfed00a2e7e4b1e0572c7ad5 Mon Sep 17 00:00:00 2001
From: k1574 <k1574@yandex.ru>
Date: Thu, 14 Jul 2022 19:13:58 +0500
Subject: [PATCH] Basic range implementation.

---
 m/cmd/goblin/main.go  |   2 +
 m/tool/grange/main.go | 122 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 124 insertions(+)
 create mode 100644 m/tool/grange/main.go

diff --git a/m/cmd/goblin/main.go b/m/cmd/goblin/main.go
index feeec9c..d165d5e 100644
--- a/m/cmd/goblin/main.go
+++ b/m/cmd/goblin/main.go
@@ -22,6 +22,7 @@ import(
 	"github.com/k1574/goblin/m/tool/read"
 	"github.com/k1574/goblin/m/tool/wc"
 	"github.com/k1574/goblin/m/tool/ftest"
+	"github.com/k1574/goblin/m/tool/grange"
 )
 
 func main() {
@@ -46,6 +47,7 @@ func main() {
 		"read" : read.Run,
 		"wc" : wc.Run,
 		"ftest" : ftest.Run,
+		"range" : grange.Run,
 	}
 
 	multitool.Main("goblin", tools)
diff --git a/m/tool/grange/main.go b/m/tool/grange/main.go
new file mode 100644
index 0000000..41c3cc2
--- /dev/null
+++ b/m/tool/grange/main.go
@@ -0,0 +1,122 @@
+package grange
+/* Concatenate files in "stdout". */
+import(
+	"os"
+	"flag"
+	"fmt"
+	"strconv"
+)
+
+var(
+	flagSet *flag.FlagSet
+	args []string
+	blockSize int
+	rangeType string
+	rangeTypeMap map[string] func() = map[string] func() {
+		"int" : IntRange,
+		"inteq" : IntRangeEq,
+		"byte" : ByteRange,
+		"rune" : RuneRange,
+	}
+)
+
+func IntRange() {
+	IntRangeHndl(func(a, b int) bool {
+		if a < b {
+			return true
+		} else {
+			return false
+		}
+	}, func(a, b int) bool {
+		if a > b {
+			return true
+		} else {
+			return false
+		}
+	})	
+}
+
+func IntRangeEq () {
+	IntRangeHndl(func(a, b int) bool {
+		if a <= b {
+			return true
+		} else {
+			return false
+		}
+	}, func(a, b int) bool {
+		if a >= b {
+			return true
+		} else {
+			return false
+		}
+	})
+}
+
+func IntRangeHndl(fn1, fn2 func(a, b int) bool) {
+	var (
+		err error
+		i, a, b int
+	)
+	step := 1
+
+	if len(args) < 2 {
+		flagSet.Usage()
+	}
+
+	if len(args) == 3 {
+		step, err = strconv.Atoi(args[2])
+		if err != nil {
+			panic(err)
+		}
+		if step == 0 {
+			flagSet.Usage()
+		}
+	}
+
+	a, err = strconv.Atoi(args[0])
+	if err != nil {
+		panic(err)
+	}
+
+	b, err = strconv.Atoi(args[1])
+	if err != nil {
+		panic(err)
+	}
+
+	if step > 0 {
+		if a>b {
+			flagSet.Usage()
+		}
+		for i=a ; fn1(i, b) ; i += step {
+			fmt.Printf("%d%s", i, "\n")
+		}
+	} else if a > b {
+		for i=a ; fn2(i, b) ; i += step {
+			fmt.Printf("%d%s", i, "\n")
+		}
+	} else {
+		flagSet.Usage()
+	}
+
+}
+
+func ByteRange() {
+}
+
+func RuneRange() {
+}
+
+func Run(arg []string) {	
+	arg0 := arg[0]
+	args = arg[1:]
+	flagSet = flag.NewFlagSet(arg0, flag.ExitOnError)
+	flagSet.StringVar(&rangeType, "t", "int", "range type")
+	flagSet.Usage = func() {
+		fmt.Fprintf(os.Stderr, "usage: %s [options] [files]\n", arg0)
+		flagSet.PrintDefaults()
+		os.Exit(1)
+	}
+	flagSet.Parse(args)
+	args = flagSet.Args()
+	rangeTypeMap[rangeType]()
+}