RosettaCodeData/Task/Strip-block-comments/Ada/strip-block-comments.ada

94 lines
3.0 KiB
Ada

with Ada.Strings.Fixed;
with Ada.Strings.Unbounded;
with Ada.Text_IO;
with Ada.Command_Line;
procedure Strip is
use Ada.Strings.Unbounded;
procedure Print_Usage is
begin
Ada.Text_IO.Put_Line ("Usage:");
Ada.Text_IO.New_Line;
Ada.Text_IO.Put_Line (" strip <file> [<opening> [<closing>]]");
Ada.Text_IO.New_Line;
Ada.Text_IO.Put_Line (" file: file to strip");
Ada.Text_IO.Put_Line (" opening: string for opening comment");
Ada.Text_IO.Put_Line (" closing: string for closing comment");
Ada.Text_IO.New_Line;
end Print_Usage;
Opening_Pattern : Unbounded_String := To_Unbounded_String ("/*");
Closing_Pattern : Unbounded_String := To_Unbounded_String ("*/");
Inside_Comment : Boolean := False;
function Strip_Comments (From : String) return String is
use Ada.Strings.Fixed;
Opening_Index : Natural;
Closing_Index : Natural;
Start_Index : Natural := From'First;
begin
if Inside_Comment then
Start_Index :=
Index (Source => From, Pattern => To_String (Closing_Pattern));
if Start_Index < From'First then
return "";
end if;
Inside_Comment := False;
Start_Index := Start_Index + Length (Closing_Pattern);
end if;
Opening_Index :=
Index
(Source => From,
Pattern => To_String (Opening_Pattern),
From => Start_Index);
if Opening_Index < From'First then
return From (Start_Index .. From'Last);
else
Closing_Index :=
Index
(Source => From,
Pattern => To_String (Closing_Pattern),
From => Opening_Index + Length (Opening_Pattern));
if Closing_Index > 0 then
return From (Start_Index .. Opening_Index - 1) &
Strip_Comments
(From (
Closing_Index + Length (Closing_Pattern) .. From'Last));
else
Inside_Comment := True;
return From (Start_Index .. Opening_Index - 1);
end if;
end if;
end Strip_Comments;
File : Ada.Text_IO.File_Type;
begin
if Ada.Command_Line.Argument_Count < 1
or else Ada.Command_Line.Argument_Count > 3
then
Print_Usage;
return;
end if;
if Ada.Command_Line.Argument_Count > 1 then
Opening_Pattern := To_Unbounded_String (Ada.Command_Line.Argument (2));
if Ada.Command_Line.Argument_Count > 2 then
Closing_Pattern :=
To_Unbounded_String (Ada.Command_Line.Argument (3));
else
Closing_Pattern := Opening_Pattern;
end if;
end if;
Ada.Text_IO.Open
(File => File,
Mode => Ada.Text_IO.In_File,
Name => Ada.Command_Line.Argument (1));
while not Ada.Text_IO.End_Of_File (File => File) loop
declare
Line : constant String := Ada.Text_IO.Get_Line (File);
begin
Ada.Text_IO.Put_Line (Strip_Comments (Line));
end;
end loop;
Ada.Text_IO.Close (File => File);
end Strip;