rtyler
/
fucked-ada
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Fix up the looping logic

This commit is contained in:
R. Tyler Croy 2011-07-04 20:40:48 -07:00
parent 8ffe968b2d
commit 35f270a6ee
1 changed files with 15 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
fucked.adb
View File

@ -25,20 +25,20 @@ procedure Fucked is
Code : Characters.Vector;
procedure Interpret (Code : Characters.Vector) is
procedure Interpret (Code : in Characters.Vector) is
Stack : Stack_Type;
Loop_Stack : Numbers.Vector;
Position, Offset, Current : Natural := 0;
begin
while Offset < Natural (Code.Length) loop
Current := Stack (Position);
Offset := Offset + 1;
case Code.Element (Offset - 1) is
case Code.Element (Offset) is
-- increment the data pointer (to point to the next cell to the
-- right).
when '>' =>
Position := Position + 1;
Offset := Offset + 1;
if Stack'Length < Position then
raise Stack_Overflow;
@ -52,19 +52,23 @@ procedure Fucked is
end if;
Position := Position - 1;
Offset := Offset + 1;
-- increment (increase by one) the byte at the data pointer.
when '+' =>
Stack (Position) := Current + 1;
Offset := Offset + 1;
-- decrement (decrease by one) the byte at the data pointer.
when '-' =>
Stack (Position) := Current - 1;
Offset := Offset + 1;
-- output a character, the ASCII value of which being the byte at
-- the data pointer.
when '.' =>
Put (Character'Val (Stack (Position)));
Offset := Offset + 1;
-- accept one byte of input, storing its value in the byte at the
-- data pointer.
@ -75,8 +79,10 @@ procedure Fucked is
-- the instruction pointer forward to the next command, jump it
-- forward to the command after the matching ] command*.
when '[' =>
if Current > 0 then
Loop_Stack.Append (Offset);
Offset := Offset + 1;
if Current /= 0 then
Loop_Stack.Append (Offset - 1);
else
-- If the counter is back to zero then we need to jump
-- ahead to the corresponding ']' for this loop
@ -84,7 +90,7 @@ procedure Fucked is
Count_Back : Natural := 1;
begin
while Count_Back > 0 loop
case Code.Element (Count_Back) is
case Code.Element (Offset) is
when ']' =>
Count_Back := Count_Back - 1;
@ -104,20 +110,11 @@ procedure Fucked is
-- moving the instruction pointer forward to the next command,
-- jump it back to the command after the matching [ command*.
when ']' =>
declare
Back_To : constant Natural := Loop_Stack.Element (
Integer (Loop_Stack.Length - 1));
Counter : constant Natural := Stack (Position);
begin
if Counter = 0 then
Numbers.Delete_Last (Loop_Stack);
else
Offset := Back_To;
end if;
end;
Offset := Loop_Stack.Element (Integer (Loop_Stack.Length - 1));
Numbers.Delete_Last (Loop_Stack);
when others =>
null;
Offset := Offset + 1;
end case;
end loop;