Author: Jonas Bilinkevicius

I need to save and restore Font selections to a text file. I was able to convert 
all the font attributes except for style to and from strings using one line 
expressions.

Answer:

Solve 1:

Here's one way of doing it:
1   
2   function StyleToStr(Style: TFontStyles): string;
3   begin
4     SetLength(Result, 4);
5     {T = true, S = false 83 is ordinal value of S, if true then S + 1 (84) = T}
6     Result[1] := Char(Integer(fsBold in Style) + 83);
7     Result[2] := Char(Integer(fsItalic in Style) + 83);
8     Result[3] := Char(Integer(fsUnderline in Style) + 83);
9     Result[4] := Char(Integer(fsStrikeOut in Style) + 83);
10    {replace all S to F's if you like}
11    Result := StringReplace(Result, 'S', 'F', [rfReplaceAll]);
12  end;
13  
14  function StrToStyle(Str: string): TFontStyles;
15  begin
16    Result := [];
17    {T = true, S = false}
18    if Str[1] = 'T' then
19      Include(Result, fsBold);
20    if Str[2] = 'T' then
21      Include(Result, fsItalic);
22    if Str[3] = 'T' then
23      Include(Result, fsUnderLine);
24    if Str[4] = 'T' then
25      Include(Result, fsStrikeOut);
26  end;



Solve 2:

I'd suggest this:
27  
28  function StyleToStr(Style: TFontStyles): string;
29  const
30    Chars: array[Boolean] of Char = ('F', 'T');
31  begin
32    SetLength(Result, 4);
33    Result[1] := Chars[fsBold in Style];
34    Result[2] := Chars[fsItalic in Style];
35    Result[3] := Chars[fsUnderline in Style];
36    Result[4] := Chars[fsStrikeOut in Style];
37  end;



Solve 3:

A more algorithmic approach:
38  
39  function FontStylesToStr(Style: TFontStyles): string;
40  var
41    I: TFontStyle;
42  begin
43    SetLength(Result, High(TFontStyle) + 1);
44    for I := Low(TFontStyle) to High(TFontStyle) do
45      if I in Style then
46        Result[Ord(I) + 1] := 'F'
47      else
48        Result[Ord(I) + 1] := 'T';
49  end;
50  
51  function StrToFontStyles(Str: string): TFontStyles;
52  var
53    I: TFontStyle;
54  begin
55    Result := [];
56    for I := Low(TFontStyle) to High(TFontStyle) do
57      if Str[Ord(I) + 1] = 'T' then
58        Include(Result, I);
59  end;



Solve 4:

May I propose that you save the font style using a numeric representation of the 
bit pattern. One special consideration during the conversion would be the size of 
the enumeration. That is, make sure you use an integer type that has the same 
boundary as the set type. For example, there are four possible font styles in 
TFontStyles, it would be stored as a byte.
60  
61  function FontStylesToInt(Styles: TFontStyles): Integer;
62  begin
63    Result := byte(Styles)
64  end;
65  
66  function IntToFontStyles(Value: integer): TFontStyles;
67  begin
68    Result := TFontStyles(byte(Value))
69  end;


If you are a purist, replace 'integer's with 'byte's