integrated readline

cmd/repl.go

@@ -20,16 +20,15 @@ package main
 import (
     "os"
     "fmt"
-    "bufio"
-    "strings"
     "strconv"
+    "github.com/chzyer/readline"
     "git.callpipe.com/aidan/shs/ast"
     "git.callpipe.com/aidan/shs/log"
     "git.callpipe.com/aidan/shs/stdlib"
 )
 
 const (
-    def_prompt  string = "λ"
+    def_prompt  string = "λ "
 )
 
 func setLogLvl() {
@@ -59,44 +58,31 @@ func main() {
     ast.InitVarTable(vars)
     ast.SyncTablesWithOSEnviron = true
 
-    useHist := false
-    var histFile *os.File
     var err error
 
-    if hist != "" {
-        useHist = true
-        histFile, err = os.OpenFile(hist, os.O_RDWR|os.O_CREATE, 0755)
-        if err != nil {
-            useHist = false
-            log.Log(log.ERR, "coudlnt open histfile: " + err.Error(), "init")
-        }
-    }
-
     if prompt == "" {
         prompt = def_prompt
     }
 
-    // TODO: is bufio right for this?
+    rl, err := readline.NewEx(&readline.Config{
-    reader := bufio.NewReader(os.Stdin)
+        Prompt: prompt,
+        HistoryFile: hist,
+        InterruptPrompt: "^C",
+    })
+
+    defer rl.Close()
+    if err != nil {
+        log.Log(log.ERR, "Couldnt initialize readline: " + err.Error(), "repl")
+        return
+    }
+
     for {
         setLogLvl()
-        fmt.Print(prompt + " ")
+        text, err := rl.Readline()
-        text, err := reader.ReadString('\n')
         if err != nil {
             log.Log(log.ERR, "couldnt read user input: " + err.Error(), "repl")
         }
 
-        // TODO: replace with a regex
-        text = strings.Replace(text, "\r\n", "", -1)
-        text = strings.Replace(text, "\n", "", -1)
-
-        if useHist {
-            _, err  = histFile.Write([]byte(text + "\n"))
-            if err != nil {
-                log.Log(log.DEBUG, "couldnt write to histfile: " + err.Error(), "repl")
-            }
-        }
-
         userInput := ast.Lex(text)
         if userInput == nil {
             // errors handled in Lex

go.mod

@@ -1,3 +1,5 @@
 module git.callpipe.com/aidan/shs
 
 go 1.14
+
+require github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e // indirect

go.sum

@@ -0,0 +1,2 @@
+github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e h1:fY5BOSpyZCqRo5OhCuC+XN+r/bBCmeuuJtjz+bCNIf8=
+github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=

stdlib/stdlib.go

@@ -114,7 +114,19 @@ func GenFuncTable() ast.FuncTable {
             TimesCalled:     0,
             Args:            1,
         },
+
+        "exit": &ast.Function{
+            Function:     exit,
+            Name:       "exit",
+            TimesCalled      0,
+            Args:            0,
+        },
     }
 
     return stdlib
 }
+
+func exit_shell(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
+    os.Exit(0)
+    return nil // I hope execution doesnt get here
+}