From 5b246e6238201125c88ab74e17e46e9aaa9ac70d Mon Sep 17 00:00:00 2001
From: Joop Kiefte <ikojba@gmail.com>
Date: Sat, 17 Oct 2020 14:28:34 +0300
Subject: Add newop operator

---
 main.go      | 65 ++++++++++++++++++++++++++++++------------------------------
 operators.go | 49 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 33 deletions(-)
 create mode 100644 operators.go

diff --git a/main.go b/main.go
index c6d1268..8a65cef 100644
--- a/main.go
+++ b/main.go
@@ -3,11 +3,15 @@ package main
 import (
 	"bufio"
 	"os"
-	"strings"
 	"strconv"
+	"strings"
 )
 
-type operation func(*[]int, *int) string
+type forthfunc func(*[]int, *int, []string) string
+type operation struct {
+	op        forthfunc
+	readuntil string
+}
 type numberError string
 type bufferError string
 
@@ -16,31 +20,13 @@ func (n bufferError) Error() string { return string(n) }
 
 var stack []int
 var stackpointer int
-var dictionary = map[string]operation{
-	"base" : func(st *[]int, stp *int) string {
-		base, _ := getvalue(st, stp)
-		r, err := getvalue(st, stp)
-		if err != nil {
-			return err.Error()
-		}
-		return strconv.FormatInt(int64(r), base)
-	},
-	"+" : func(st *[]int, stp *int) string {
-		n1, _ := getvalue(st, stp)
-		n2, err := getvalue(st, stp)
-		if err != nil {
-			return err.Error()
-		}
-		err = putvalue(st, stp, n1+n2)
-		if err != nil {
-			return err.Error()
-		}
-		return "*"
-	},
-	"quit": func(_ *[]int, _ *int) string {
-		os.Exit(0)
-		return "should have quit"
-	},
+var dictionary = make(map[string]operation)
+
+func forth(code string) forthfunc {
+	op := func(st *[]int, stp *int, _ []string) string {
+		return eval(code, nil)
+	}
+	return forthfunc(op)
 }
 
 func getvalue(st *[]int, stp *int) (int, error) {
@@ -54,7 +40,7 @@ func getvalue(st *[]int, stp *int) (int, error) {
 }
 
 func putvalue(st *[]int, stp *int, n int) error {
-	if *stp == int(^uint(0) >> 1) { // check for maxint
+	if *stp == int(^uint(0)>>1) { // check for maxint
 		return bufferError("buffer overflow")
 	}
 	*st = append(*st, n)
@@ -107,13 +93,28 @@ func number(st *[]int, stp *int, cmd string) error {
 
 func eval(code string, inerr error) string {
 	if inerr != nil {
+		if code == "" {
+			os.Exit(0)
+		}
 		return "Error before evaluating code: " + inerr.Error()
 	}
 	var value string
-	for _, cmd := range strings.Split(code, " ") {
+	cmds := strings.Split(code, " ")
+	for i := 0; i < len(cmds); i++ {
+		cmd := cmds[i]
 		op, ok := dictionary[cmd]
 		if ok {
-			value = op(&stack, &stackpointer)
+			var read []string
+			if op.readuntil != "" {
+				for j, c := range cmds[i+1:] {
+					if c == op.readuntil {
+						read = cmds[i+1 : i+j+1]
+						i += j + 1
+						break
+					}
+				}
+			}
+			value = op.op(&stack, &stackpointer, read)
 			continue
 		}
 		err := number(&stack, &stackpointer, cmd)
@@ -126,9 +127,7 @@ func eval(code string, inerr error) string {
 
 func main() {
 	stdin := bufio.NewReader(os.Stdin)
-	dictionary["."] = func(st *[]int, stp *int) string {
-		return eval("10 base", nil)
-	}
+	prelude()
 	for {
 		println(eval(read(stdin)))
 	}
diff --git a/operators.go b/operators.go
new file mode 100644
index 0000000..9fd3769
--- /dev/null
+++ b/operators.go
@@ -0,0 +1,49 @@
+package main
+
+import (
+	"strconv"
+	"os"
+	"strings"
+)
+
+func prelude() {
+	dictionary[":"] = operation{op: newop, readuntil: ";"}
+	dictionary["base"] = operation{op: base}
+	dictionary["+"] = operation{op: add}
+	dictionary["quit"] = operation{op: quit}
+	dictionary["."] = operation{op: forth("10 base")}
+}
+
+func newop(st *[]int, stp *int, code []string) string {
+	if len(code) > 0 {
+		dictionary[code[0]] = operation{op: forth(strings.Join(code[1:], " "))}
+	}
+	return ""
+}
+
+func base(st *[]int, stp *int, _ []string) string {
+	base, _ := getvalue(st, stp)
+	r, err := getvalue(st, stp)
+	if err != nil {
+		return err.Error()
+	}
+	return strconv.FormatInt(int64(r), base)
+}
+
+func add(st *[]int, stp *int, _ []string) string {
+	n1, _ := getvalue(st, stp)
+	n2, err := getvalue(st, stp)
+	if err != nil {
+		return err.Error()
+	}
+	err = putvalue(st, stp, n1+n2)
+	if err != nil {
+		return err.Error()
+	}
+	return "*"
+}
+
+func quit(_ *[]int, _ *int, _ []string) string {
+	os.Exit(0)
+	return "should have quit"
+}
-- 
cgit v1.2.3-70-g09d2