example_test.go

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package scanner_test
     6  
     7  import (
     8  	"fmt"
     9  	"go/scanner"
    10  	"go/token"
    11  )
    12  
    13  func ExampleScanner_Scan() {
    14  	// src is the input that we want to tokenize.
    15  	src := []byte("cos(x) + 1i*sin(x) // Euler")
    16  
    17  	// Initialize the scanner.
    18  	var s scanner.Scanner
    19  	fset := token.NewFileSet()                      // positions are relative to fset
    20  	file := fset.AddFile("", fset.Base(), len(src)) // register input "file"
    21  	s.Init(file, src, nil /* no error handler */, scanner.ScanComments)
    22  
    23  	// Repeated calls to Scan yield the token sequence found in the input.
    24  	for {
    25  		pos, tok, lit := s.Scan()
    26  		if tok == token.EOF {
    27  			break
    28  		}
    29  		fmt.Printf("%s\t%s\t%q\n", fset.Position(pos), tok, lit)
    30  	}
    31  
    32  	// output:
    33  	// 1:1	IDENT	"cos"
    34  	// 1:4	(	""
    35  	// 1:5	IDENT	"x"
    36  	// 1:6	)	""
    37  	// 1:8	+	""
    38  	// 1:10	IMAG	"1i"
    39  	// 1:12	*	""
    40  	// 1:13	IDENT	"sin"
    41  	// 1:16	(	""
    42  	// 1:17	IDENT	"x"
    43  	// 1:18	)	""
    44  	// 1:20	COMMENT	"// Euler"
    45  	// 1:28	;	"\n"
    46  }
    47
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