library: go/{token, scanner}

_cmptest/goscandemo/scan.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"fmt"
+	"go/scanner"
+	"go/token"
+)
+
+func main() {
+	// src is the input that we want to tokenize.
+	src := []byte("cos(x) + 1i*sin(x) // Euler")
+
+	// Initialize the scanner.
+	var s scanner.Scanner
+	fset := token.NewFileSet()                      // positions are relative to fset
+	file := fset.AddFile("", fset.Base(), len(src)) // register input "file"
+	s.Init(file, src, nil /* no error handler */, scanner.ScanComments)
+
+	// Repeated calls to Scan yield the token sequence found in the input.
+	for {
+		pos, tok, lit := s.Scan()
+		if tok == token.EOF {
+			break
+		}
+		fmt.Printf("%s\t%s\t%q\n", fset.Position(pos), tok, lit)
+	}
+}