parser: add comments and [...]; main: add file mode

main.go

@@ -2,7 +2,9 @@ package main
 
 import (
   "fmt"
+  "io/ioutil"
   "log"
+  "os"
   "strings"
 
   "github.com/chzyer/readline"
@@ -11,7 +13,7 @@ import (
   "github.com/hellerve/argos/parser"
 )
 
-func main() {
+func runRepl() {
   rl, err := readline.New("argos> ")
 
   if err != nil {
@@ -22,13 +24,13 @@ func main() {
 
   e := eval.ParentEnv()
   for {
-    prompt, err := rl.Readline()
+    input, err := rl.Readline()
 
     if err != nil {
       return
     }
 
-    parsed, err, unconsumed := parser.Parse(prompt)
+    parsed, err, unconsumed := parser.Parse(input)
 
     if err != nil {
       fmt.Println(err)
@@ -52,3 +54,43 @@ func main() {
     fmt.Println(evald.Pretty())
   }
 }
+
+func runFile(path string) {
+  e := eval.ParentEnv()
+  input, err := ioutil.ReadFile(path)
+
+  if err != nil {
+    fmt.Println(err)
+    return
+  }
+
+  parsed, err, unconsumed := parser.Parse(string(input))
+
+  if err != nil {
+    fmt.Println(err)
+    return
+  }
+
+  if len(unconsumed) != 0 {
+    fmt.Println("Unconsumed input:", strings.Join(unconsumed, " "))
+    return
+  }
+
+  evald, err := eval.Eval(parsed, e)
+
+  if err != nil {
+    fmt.Println(err)
+    return
+  }
+
+  fmt.Println(evald.Pretty())
+}
+
+func main() {
+  args := os.Args
+  if len(args) == 1 {
+    runRepl()
+  } else {
+    runFile(os.Args[1])
+  }
+}