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implemented syntax checking of 'do'

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hyung-hwan
2014-02-17 09:22:36 +00:00
parent b87ce61c29
commit 5cfa32e7d9
1 changed files with 105 additions and 6 deletions
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111
lib/h2-scheme-execute-evaluate.adb
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@ -358,24 +358,44 @@ procedure Evaluate is
procedure Evaluate_Do_Syntax is
pragma Inline (Evaluate_Do_Syntax);
Synlist: Object_Pointer;
Ptr1: Object_Pointer;
Ptr2: Object_Pointer;
Ptr3: Object_Pointer;
begin
-- (do <bindings> <clause> <body>)
-- <bindings> should be of the form: ((<variable 1> <init 1> <step 1>) ...)
-- <clause> should be of the form: (<test> <expression> ...)
-- <body> is zero or more expressions.
--
-- * evaluate <init>.
-- * bind <variable> with the result.
-- * evaluate <test>
-- * if the result is false, evaluate <body>. evaluate <step>.
-- store it into <variable> and go back to evaluate <test>
-- * if the result is true, evaluate <expression> and exit.
--
-- (let ((x '(1 3 5 7 9)))
-- (do ((x x (cdr x))
-- (sum 0 (+ sum (car x)))) ; <bindings>
-- (sum 0 (+ sum (car x)))) ; <bindings> x and sum
-- ((null? x) sum) ; <clause>. if <test> is true, exit do with sum.
-- )
-- )
--
-- (do ((i 0 (+ i 1)))
-- ((= i 5) i)
-- (display i) ; <body> downwards
-- (do (
-- (i 0 (+ i 1)) ; i = 0, for each iteration, +1
-- (j 0 (+ j 2)) ; j = 0, for each iteration, +2
-- )
--
-- ((= i 5) i) ; exit returning i if i becomes 5
--
-- (display (* i j)) ; evaluate these until it exits
-- (newline)
-- )
--
-- Infinite loop samples:
-- (do () (#f) (display i))
-- (do ((i 0)) (#f) (display i))
-- (do ((i 0)) (#f) (display i))
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "do"
@ -383,9 +403,88 @@ procedure Evaluate is
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
Ada.Text_IO.Put_LINE ("UNIMPLEMENTED");
raise Evaluation_Error;
Ptr1 := Operand; -- <bindings> list
if not Is_Cons(Ptr1) then
-- (do)
-- (do . 10)
Ada.Text_IO.Put_LINE ("NO BIDNIGNS FOR DO");
raise Syntax_Error;
end if;
Ptr2 := Get_Car(Ptr1); -- <bindings>
while Is_Cons(Ptr2) loop
Ptr3 := Get_Car(Ptr2); -- <binding>
if not Is_Cons(Ptr3) then
-- (do (i) (#f))
Ada.Text_IO.Put_Line ("INVALID BINDING FOR DO");
raise Syntax_Error;
end if;
if not Is_Symbol(Get_Car(Ptr3)) then -- <variable>
-- (do ((10 10)) (#f))
Ada.Text_IO.Put_Line ("INVALID BINDING VARIABLE FOR DO");
raise Syntax_Error;
end if;
Ptr3 := Get_Cdr(Ptr3); -- <init> cons
if not Is_Cons(Ptr3) then
-- (do ((i . 10)) (#f))
Ada.Text_IO.Put_Line ("NO INIT IN DO BINDING");
raise Syntax_Error;
end if;
-- Get_Car(Ptr3); -- <init>
Ptr3 := Get_Cdr(Ptr3); -- <step> cons
if Is_Cons(Ptr3) then
-- Get_Car(Ptr3); -- <step>
if Get_Cdr(Ptr3) /= Nil_Pointer then
-- (do ((i 0 10 20)) ... )
Ada.Text_IO.PUT_Line ("TOO MANY STEP EXPRESSIONS IN DO BINDING");
raise Syntax_Error;
end if;
elsif Ptr3 /= Nil_Pointer then
-- (do ((i 0 . 10)) ... )
Ada.Text_IO.Put_Line ("FUCKING CDR in DO BIDNING");
raise Syntax_Error;
end if;
Ptr2 := Get_Cdr(Ptr2);
end loop;
if Ptr2 /= Nil_Pointer then
-- (do 10 . 10)
-- (do 10 (#f))
-- (do ((i 10) (j 20) . 10) (#f))
Ada.Text_IO.Put_LINE ("INVALID BINDINGS FOR DO");
raise Syntax_Error;
end if;
Ptr1 := Get_Cdr(Ptr1); -- <clause>
if not Is_Cons(Ptr1) then
-- (do ( (i 10) (j 20)))
-- (do ( (i 10) (j 20)) . #f)
Ada.Text_IO.Put_LINE ("NO CLAUSE FOR DO");
raise Syntax_Error;
end if;
Ptr2 := Get_Car(Ptr1); -- <test> in clause;
if not Is_Cons(Ptr2) then
-- (do ( (i 10) (j 20)) #f)
Ada.Text_IO.Put_Line ("INVALID CLAUSE TEST FOR DO");
raise Syntax_Error;
end if;
if Get_Last_Cdr(Ptr2) /= Nil_Pointer then
-- (do ( (i 10) (j 20)) (#f . 10))
-- (do ( (i 10) (j 20)) (#f 20 . 10))
Ada.Text_IO.Put_LINE ("FUCKING CDR IN CLAUSE FOR DO");
raise Syntax_Error;
end if;
if Get_Last_Cdr(Ptr1) /= Nil_Pointer then
-- (do ( (i 10) (j 20 10)) (#f 20) . 10)
Ada.Text_IO.Put_LINE ("FUCKING CDR IN BODY FOR DO");
raise Syntax_Error;
end if;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;