prototype repl

cmd/repl.go

@@ -0,0 +1,106 @@
+/*   SHS: Syntactically Homogeneous Shell
+ *   Copyright (C) 2019  Aidan Hahn
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package main
+
+import (
+    "fmt"
+    "bufio"
+    "strconv"
+    "git.callpipe.com/aidan/shs/ast"
+    "git.callpipe.com/aidan/shs/log"
+)
+
+const (
+    def_prompt  string = "λ"
+)
+
+func setLogLvl() {
+    loglvl := os.Getenv("SH_LOGGING")
+    if loglvl != "" {
+        llvl, ok := strconv.ParseInt(loglvl, 10, 8)
+        if !ok {
+            log.Log(log.Err,
+                    "couldnt parse log level",
+                    "init")
+        } else {
+            log.SetLogLvl(llvl)
+        }
+    }
+}
+
+func main() {
+    debug  := os.Getenv("SH_DEBUG_MODE")
+    hist   := os.Getenv("SH_HIST_FILE")
+    prompt := os.Getenv("SHS_SH_PROMPT")
+
+    var vars ast.VarTable
+    var funcs ast.VarTable
+
+    useHist := false
+    var histFile os.File
+    var err error
+
+    if hist != "" {
+        useHist = true
+        histFile, err = os.OpenFile(histFile, os.O_RDWR|os.O_CREATE, 0755)
+        if err != nil {
+            useHist = false
+            log.Log(log.ERR, "coudlnt open histfile: " + err, "init")
+        }
+    }
+
+    if prompt == "" {
+        prompt = def_prompt
+    }
+
+    // TODO: is bufio right for this?
+    reader := bufio.NewReader(os.Stdin)
+    for {
+        setLogLvl()
+        fmt.Print(prompt + " ")
+        text, err := reader.ReadString('\n')
+        if err != nil {
+            log.Log(log.ERR, "couldnt read user input: " + err, "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, "repl")
+            }
+        }
+
+        userInput := ast.Lex(text)
+        if userInput == nil {
+            // errors handled in Lex
+            // TODO: return an error instead
+            continue
+        }
+
+        if debug != "" {
+            log.PrintSExprsIndividually(userInput)
+        }
+
+        result := userInput.Eval(funcs, vars)
+        fmt.Println(result.String() + "\n")
+    }
+}