doc: improve comments, pass lint

Also improve the setup of golangci-lint.

1 files changed, 11 insertions, 32 deletions

diff --git a/main.go b/main.go
index b0ca700..0e95bd4 100644
--- a/main.go
+++ b/main.go
@@ -1,12 +1,11 @@
+// The parscan command interprets programs.
 package main
 
 import (
 	"flag"
 	"fmt"
-	"io"
 	"log"
 	"os"
-	"strings"
 
 	"github.com/mvertes/parscan/interpreter"
 	"github.com/mvertes/parscan/lang/golang"
@@ -19,7 +18,7 @@ func main() {
 	}
 }
 
-func run(arg []string) (err error) {
+func run(arg []string) error {
 	var str string
 	rflag := flag.NewFlagSet("run", flag.ContinueOnError)
 	rflag.Usage = func() {
@@ -28,46 +27,26 @@ func run(arg []string) (err error) {
 		rflag.PrintDefaults()
 	}
 	rflag.StringVar(&str, "e", "", "string to eval")
-	if err = rflag.Parse(arg); err != nil {
+	if err := rflag.Parse(arg); err != nil {
 		return err
 	}
 	args := rflag.Args()
 
 	interp := interpreter.NewInterpreter(golang.GoSpec)
-
-	var in io.Reader
 	if str != "" {
-		in = strings.NewReader(str)
-	} else {
-		in = os.Stdin
-	}
-	if len(args) > 0 {
-		if in, err = os.Open(arg[0]); err != nil {
-			return err
-		}
-		if i2, ok := in.(io.ReadCloser); ok {
-			defer i2.Close()
-		}
+		return evalStr(interp, str)
 	}
-
-	if isatty(in) {
-		return interp.Repl(in)
+	if len(args) == 0 {
+		return interp.Repl(os.Stdin)
 	}
-
-	buf, err := io.ReadAll(in)
+	buf, err := os.ReadFile(arg[0])
 	if err != nil {
 		return err
 	}
-	_, err = interp.Eval(string(buf))
-	return err
+	return evalStr(interp, string(buf))
 }
 
-// isatty returns true if the input stream is a tty (i.e. a character device).
-func isatty(in io.Reader) bool {
-	s, ok := in.(interface{ Stat() (os.FileInfo, error) })
-	if !ok {
-		return false
-	}
-	stat, err := s.Stat()
-	return err == nil && stat.Mode()&os.ModeCharDevice != 0
+func evalStr(i *interpreter.Interp, s string) error {
+	_, err := i.Eval(s)
+	return err
 }