Identifier expected in const

Question

I am having problems calling the StringChangeEx function which is replacing parts of a file path such as...

THIS: C:\Program Files (x86)\Steam\SteamApps\common\Stalker Call of Pripyat\bin
TO: C:\Program Files (x86)\Steam\SteamApps\common\Stalker Call of Pripyat_mm2\bin

As a way of backing up files before replacing them while maintaining it's original file structure.

http://www.jrsoftware.org/ishelp/index.php?topic=isxfunc_stringchangeex

#define Name "Misery Mod"
#define Description "Misery Mod Installer"
#define Version "2.0"
#define Author "Misery Mod Development Team"
#define Website "http://miserymod.com"
#define Support "support@miserymod.com"
#define Copyright "Copyright [c] 2013 Misery Mod. All Rights Reserved."
#define Executable "Stalker-COP.exe"

[Setup]
AppId={{6423E48F-04F4-4E99-9420-FDD9165A6A90}
AppName={#Name}
AppVersion={#Version}
AppVerName={#Name} {#Version}
AppPublisher={#Author}
AppPublisherURL={#Website}
AppSupportURL={#Website}
AppUpdatesURL={#Website}
AppContact={#Support}
AppComments={#Description}
AppCopyright={#Copyright}

DefaultDirName={code:DetectIP}
DirExistsWarning=no
OutputDir=debug
OutputBaseFilename=mm2-installer

Compression=lzma2/ultra64
SolidCompression=yes
InternalCompressLevel=ultra
CompressionThreads=2

VersionInfoVersion={#Version}
VersionInfoCompany={#Author}
VersionInfoDescription={#Description}
VersionInfoTextVersion={#Name} {#Version}
VersionInfoCopyright={#Copyright}
VersionInfoProductName={#Name}
VersionInfoProductVersion={#Version}
VersionInfoProductTextVersion={#Name} {#Version}

DiskSpanning=True
DiskSliceSize=1566000000
SlicesPerDisk=1

MinVersion=0,5.01
SetupIconFile=mm2.ico
UninstallDisplayIcon={uninstallexe}
ShowTasksTreeLines=True
AlwaysShowGroupOnReadyPage=True
AlwaysShowDirOnReadyPage=True
LicenseFile=agreement.rtf
WizardImageFile=mm2-sidebar.bmp
WizardSmallImageFile=mm2-header.bmp
AllowCancelDuringInstall=False
DisableProgramGroupPage=yes
UninstallDisplayName={#Name}
InfoBeforeFile=C:\Users\Nathaniel\Desktop\MM2\readme.rtf

[Run]
Filename: {app}\{#Executable}; Description: {cm:LaunchProgram, {#Name}}; Flags: nowait postinstall skipifsilent unchecked
Filename: {#Website}; Description: {cm:VisitWebsite, {#Name}}; Flags: nowait shellexec postinstall skipifsilent unchecked

[CustomMessages]
LaunchProgram=Enter the Wasteland.
VisitWebsite=Visit {#Website}.

[Languages]
Name: "English"; MessagesFile: "compiler:Default.isl"
Name: "Ukrainian"; MessagesFile: "compiler:Languages\Ukrainian.isl"

[Dirs]
Name: "{app}\_mm2"

[Files]
Source: "files\bin\*"; DestDir: {app}; Flags: ignoreversion createallsubdirs recursesubdirs; BeforeInstall: BackupFile

[Code]
var Base:String;
var Backup:String;

function DetectIP(Path:String): string;

var Steam:String;
var Retail:String;

Begin

    const Base=ExpandConstant('{pf}')+'\'; // <- Identifier expected.

    Steam:=ExpandConstant('{pf}')+'\Steam\SteamApps\common\Stalker Call of Pripyat';
    Retail:=ExpandConstant('{pf}')+'\Steam\SteamApps\common\Stalker Call of Pripyat';

    Begin
        if DirExists(Steam) then
            Base:=Steam;
    End;

    Begin
        if DirExists(Retail) then
            Base:=Retail;
    End;

    Result:=Base;

End;

procedure BackupFile();

var Folder:String;
var File:String;

Begin

    Folder:=ExpandConstant(ExtractFilePath(CurrentFileName));
    File:=ExpandConstant(CurrentFileName);
    Backup:=StringChangeEx(Folder, Base, Base+'_mm2/', false);

    MsgBox(Backup, mbInformation, MB_OK);

    Begin
        if not DirExists(Backup) then
            CreateDir(Backup);
    End;

End;

Compiler Error!
Line 89: Column 5: Identifier expected.

Answer 1

Looking for Steam location and game location:

[Code]
var
CPath: String;

function GetInstallDir(const FileName, Section: string): string;
var
  S: string;
  DirLine: Integer;
  LineCount: Integer;
  SectionLine: Integer;    
  Lines: TArrayOfString;
begin
  Result := '';
  S := '"' + Section + '"'; 
  if LoadStringsFromFile(FileName, Lines) then
  begin
    LineCount := GetArrayLength(Lines);
    for SectionLine := 0 to LineCount - 1 do
      if Trim(Lines[SectionLine]) = S then
      begin
        if (SectionLine < LineCount) and (Trim(Lines[SectionLine + 1]) = '{') then
          for DirLine := SectionLine to LineCount - 1 do
          begin
            if ((Pos('"installdir"', Lines[DirLine]) > 0) and
              (StringChangeEx(Lines[DirLine], '"installdir"', '', True) > 0)) or 
              ((Pos('"InstallDir"', Lines[DirLine]) > 0) and
              (StringChangeEx(Lines[DirLine], '"InstallDir"', '', True) > 0)) then
            begin
              S := RemoveQuotes(Trim(Lines[DirLine]));
              StringChangeEx(S, '\\', '\', True);
              Result := S;
              Exit;
            end;
            if Trim(Lines[DirLine]) = '}' then
              Exit;
          end;
        Exit;
      end;
  end;
end;

function InitializeSetup: Boolean;
var   
Path: string;
begin
  if RegQueryStringValue(HKEY_LOCAL_MACHINE, 'Software\Valve\Steam',
     'InstallPath', Path) then begin
    CPath := '';
    CPath := GetInstallDir(Path + '\config\config.vdf', '228200'); 
//here put you Game ID (this one is for Company of Heroes (new version))
       if CPath = '' then begin
          MsgBox(ExpandConstant('{cm:NoGameDetected}'), mbInformation, MB_OK);
          result := false;
       end
       else begin
          result := true;
       end;
  end
  else begin
    MsgBox(ExpandConstant('{cm:NoSteamDetected}'), mbInformation, MB_OK);
    result := false;
  end;
end;

function GetDefaultInstallPath(DefaultPath: String):String;
begin
  DefaultPath := CPath;
  Result := DefaultPath;
end;