"Go Language Programming" study (III)

One, word substitution

1 Package Main2 3 Import (4     "Bufio"5     "FMT"6     "io"7     "Io/ioutil"8     "Log"9     "OS"Ten     "Path/filepath" One     "RegExp" A     "Strings" - ) -  the varBritishamerican ="British-american.txt" -  - func init () { -Dir, _: = FilePath. Split (OS. args[0]) +Britishamerican =filepath. Join (dir, Britishamerican) -Fmt. Println ("dir%s,file%s", Dir,britishamerican) + } A  at Func Main () { -Infilename, Outfilename, err: =Filenamesfromcommandline () -     ifErr! =Nil { - FMT. PRINTLN (ERR) -Os. Exit (1) -     } inInFile, OutFile: =OS. Stdin, OS. Stdout -     ifInfilename! ="" { to         ifInFile, err = os. Open (Infilename); Err! =Nil { + log. Fatal (ERR) -         } the defer infile.close () *     } $     ifOutfilename! ="" {Panax Notoginseng         ifOutFile, err = os. Create (Outfilename); Err! =Nil { - log. Fatal (ERR) the         } + defer outfile.close () A     } the  +     ifErr = Americanise (InFile, outFile); Err! =Nil { - log. Fatal (ERR) $     } $ } -  -Func filenamesfromcommandline () (Infilename, Outfilenamestring, err Error) { the     ifLen (OS. Args) >1&& (OS. args[1] =="- H"|| Os. args[1] =="--help") { -Err = FMT. Errorf ("usage:%s [<] infile.txt [;] Outfile.txt",WuyiFilePath. Base (OS. args[0])) the         return "","", Err -     } Wu     ifLen (OS. Args) >1 { -Infilename = OS. args[1] About         ifLen (OS. Args) >2 { $Outfilename = OS. args[2] -         } -     } -     ifInfilename! =""&& Infilename = =Outfilename { ALog. Fatal ("won ' t overwrite the infile") +     } the     returnInfilename, outfilename, nil - } $  the func americanise (inFile io. Reader, OutFile io. Writer) (err error) { theReader: =Bufio. Newreader (InFile) theWriter: =Bufio. Newwriter (OutFile) the defer func () { -         ifErr = =Nil { inErr =writer. Flush () the         } the     }() About  the     varReplacer func (string)string the     ifReplacer, err = makereplacerfunction (Britishamerican); Err! =Nil { the         returnErr +     } -Wordrx: = RegExp. Mustcompile ("[a-za-z]+") theEOF: =falseBayi      for!EOF { the         varLinestring theLine, err = reader. ReadString ('\ n') -         ifErr = =io. EOF { -Err =Nil theEOF =true the}Else ifErr! =Nil { the             returnErr the         } -line =Wordrx.replaceallstringfunc (line, replacer) the         if_, Err = writer. WriteString (line); Err! =Nil { the  the             returnErr94         } the     } the     returnNil the }98  AboutFunc makereplacerfunction (filestring) (Func (string)string, error) { -Rawbytes, err: =Ioutil. ReadFile (file)101     ifErr! =Nil {102         returnNil, err103     }104Text: =string(rawbytes) theUsforbritish: = Make (map[string]string)106Lines: = Strings. Split (Text,"\ n")107      for_, Line: =Range Lines {108Fields: =strings. Fields (line)109         ifLen (fields) = =2 { theusforbritish[fields[0]] = fields[1]111         } the     }113  the     returnFunc (Wordstring)string { the         ifUsword, found: =Usforbritish[word]; found { the             returnUsword117         }118         returnWord119 }, Nil -}

The format is finally right.

In this function, I think there are a few points, one is closure, one is a regular replacement, there is a defer to do the funeral ~

A simple understanding of closures, when constructing a function, while allowing the function to bring some other content such as data, such as the definition of this replacer function, the first definition of the Replacer private data map, and then return the use of this map function. This allows you to use this map point data when calling Replacer. (It seems to be a bit confusing.) ）

The regular and the defer have nothing to say.

"Go Language Programming" study (III)