Embed Directive in Pascal

Here’s the translation of the Go code to Pascal, formatted in Markdown suitable for Hugo:

Our first program demonstrates the use of file embedding. Here’s the full source code:

program EmbedDirective;

{$mode objfpc}{$H+}

uses
  Classes, SysUtils;

const
  FileString: string = {$i 'folder/single_file.txt'};
  FileByte: array of byte = {$i 'folder/single_file.txt'};

type
  TFolderFiles = record
    SingleFile: string;
    File1Hash: string;
    File2Hash: string;
  end;

var
  Folder: TFolderFiles;

begin
  // Print out the contents of 'single_file.txt'
  WriteLn(FileString);
  WriteLn(TEncoding.UTF8.GetString(FileByte));

  // Retrieve some files from the embedded folder
  Folder.SingleFile := {$i 'folder/single_file.txt'};
  Folder.File1Hash := {$i 'folder/file1.hash'};
  Folder.File2Hash := {$i 'folder/file2.hash'};

  WriteLn(Folder.File1Hash);
  WriteLn(Folder.File2Hash);
end.

In Pascal, we don’t have a direct equivalent to Go’s embed package or the //go:embed directive. However, we can use compiler directives to include file contents at compile-time.

The {$i 'filename'} directive in Pascal is used to include the contents of a file directly into the source code at compile-time. This is similar to the //go:embed directive in Go, but with some limitations.

We define constant strings and byte arrays to hold the contents of the embedded files. For more complex scenarios, we define a record type TFolderFiles to represent a simple file system structure.

To run this example, you need to create the necessary files and folders:

$ mkdir folder
$ echo "hello pascal" > folder/single_file.txt
$ echo "123" > folder/file1.hash
$ echo "456" > folder/file2.hash

Then compile and run the Pascal program:

$ fpc embed_directive.pas
$ ./embed_directive
hello pascal
hello pascal
123
456

Note that this Pascal implementation is a simplified version of the Go example. Pascal doesn’t have built-in support for a virtual file system like Go’s embed.FS, so we’ve used a more basic approach to demonstrate the concept of file embedding.