hcl/lib/h2-scheme-execute-evaluate.adb

1110 lines
34 KiB
Ada

separate (H2.Scheme.Execute)
procedure Evaluate is
--pragma Inline (Evaluate);
Operand: aliased Object_Pointer;
-- ----------------------------------------------------------------
generic
Result: Object_Pointer; -- Result to return if no <test> expressions exist.
Opcode: Opcode_Type; -- Switch to this opcode to evaluate the next <test>.
procedure Generic_And_Or_Syntax;
procedure Generic_And_Or_Syntax is
begin
-- (and <test1> <test2> ...)
-- (and (= 2 2) (> 2 1)) ==> #t
-- (and (= 2 2) (< 2 1)) ==> #f
-- (and (= 2 2) (< 2 1) (= 3 3)) ==> #f
-- (and 1 2 'c '(f g)) ==> (f g)
-- (and) ==> #t
Operand := Get_Cdr(Operand); -- Skip "And"
if Operand = Nil_Pointer then
-- (and)
Return_Frame (Interp, Result);
elsif not Is_Cons(Operand) or else Get_Last_Cdr(Operand) /= Nil_Pointer then
-- (and . 10)
-- (and 1 2 . 10)
Ada.Text_IO.Put_LINE ("FUCKING CDR FOR DEFINE");
raise Syntax_Error;
else
--Switch_Frame (Interp.Stack, Opcode, Get_Cdr(Operand), Nil_Pointer); -- <test2> onwards
--Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Operand)); -- <test1>
Switch_Frame (Interp.Stack, Opcode_Evaluate_Object, Get_Car(Operand), Nil_Pointer); -- <test2> onwards
Push_Subframe (Interp, Opcode, Get_Cdr(Operand)); -- <test1> onwards
end if;
end Generic_And_Or_Syntax;
procedure Evaluate_And_Syntax is new Generic_And_Or_Syntax(True_Pointer, Opcode_And_Finish);
procedure Evaluate_Or_Syntax is new Generic_And_Or_Syntax(False_Pointer, Opcode_Or_Finish);
-- ----------------------------------------------------------------
procedure Evaluate_Begin_Syntax is
pragma Inline (Evaluate_Begin_Syntax);
Synlist: Object_Pointer;
begin
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "begin"
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
if Operand /= Nil_Pointer and then
Get_Last_Cdr(Operand) /= Nil_Pointer then
Ada.Text_IO.Put_LINE ("FUCKNING CDR FOR BEGIN");
raise Syntax_Error;
end if;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
if Operand = Nil_Pointer then
-- (begin)
-- Return nil to the upper frame for (begin).
Return_Frame (Interp, Nil_Pointer);
else
Switch_Frame (Interp.Stack, Opcode_Grouped_Call, Operand, Nil_Pointer);
end if;
end Evaluate_Begin_Syntax;
-- ----------------------------------------------------------------
procedure Evaluate_Case_Syntax is
pragma Inline (Evaluate_Case_Syntax);
Synlist: Object_Pointer;
Ptr1: Object_Pointer;
Ptr2: Object_Pointer;
Ptr3: Object_Pointer;
begin
-- (case <key> <clause 1> <clause 2> ...)
-- <key> is an expression.
-- <clause> should be of the form:
-- ((<datum 1> ...) <expression 1> <expression 2> ...)
-- the last <clause> may be an else clause of the form:
-- (else <expression 1> <expression 2> ...)
--
-- (case (* 2 3)
-- ((2 3 5 7) 'prime)
-- ((1 4 6 8 9) 'composite))
--
-- (case (car '(c d))
-- ((a e i o u) 'vowel)
-- ((w y) 'semivowel)
-- (else 'consonant))
--
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "case"
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
if Not Is_Cons(Operand) then
-- e.g) (case)
-- (case . 10)
Ada.Text_IO.Put_LINE ("NO KEY FOR CASE");
raise Syntax_Error;
end if;
--Key := Get_Car(Operand); -- <key>
Ptr1 := Get_Cdr(Operand); -- <clause> list.
while Is_Cons(Ptr1) loop
Ptr2 := Get_Car(Ptr1); -- <clause>
if Get_Last_Cdr(Ptr2) /= Nil_Pointer then
Ada.Text_IO.Put_Line ("FUCKING CDR FOR CASE CLAUSE");
raise Syntax_Error;
end if;
Ptr3 := Get_Car(Ptr2); -- <datum> list or 'else'
if Is_Cons(Ptr3) then
if Get_Last_Cdr(Ptr3) /= Nil_Pointer then
Ada.Text_IO.Put_LINE ("FUCKING CDR FOR CASE DATUM");
raise Syntax_Error;
end if;
elsif Ptr3 = Interp.Else_Symbol then
-- check <test>. if it's else, it should be in the last clause.
if Is_Cons(Get_Cdr(Ptr1)) then
Ada.Text_IO.Put_Line ("ELSE NOT IN THE LAST CASE CLAUSE");
raise Syntax_Error;
end if;
else
Ada.Text_IO.Put_LINE ("INVALID DATUM FOR CASE");
raise Syntax_Error;
end if;
if Get_Cdr(Ptr2) = Nil_Pointer then
Ada.Text_IO.Put_Line ("NO EXPRESSION IN CASE CLAUSE");
raise Syntax_Error;
end if;
Ptr1 := Get_Cdr(Ptr1); -- next <clause> list
end loop;
if Ptr1 /= Nil_Pointer then
Ada.Text_IO.Put_Line ("FUCKING LAST CLAUSE FOR CASE");
raise Syntax_Error;
end if;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
Switch_Frame (Interp.Stack, Opcode_Evaluate_Object, Get_Car(Operand), Nil_Pointer); -- <key>
Push_Subframe (Interp, Opcode_Case_Finish, Get_Cdr(Operand)); -- <clause> list
end Evaluate_Case_Syntax;
-- ----------------------------------------------------------------
procedure Evaluate_Cond_Syntax is
pragma Inline (Evaluate_Cond_Syntax);
Synlist: Object_Pointer;
begin
-- cond <clause 1> <clause 2> ...
-- A clause should be of the form:
-- (<test> <expression> ...)
-- the last clause may be an else clause of the form:
-- (else <expression> ...)
--
-- (cond ((> 3 2) 'greater)
-- ((< 3 2) 'less)) => greater
-- (cond ((> 3 3) 'greater)
-- ((< 3 3) 'less)
-- (else 'equal)) => equal
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "cond". <clause> list
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
if Not Is_Cons(Operand) then
-- e.g) (cond)
-- (cond . 10)
Ada.Text_IO.Put_LINE ("NO CLAUSE FOR COND");
raise Syntax_Error;
end if;
declare
Ptr1: Object_Pointer := Operand;
Ptr2: Object_Pointer;
begin
loop
Ptr2 := Get_Car(Ptr1); -- <clause>
if not Is_Cons(Ptr2) then
Ada.Text_IO.Put_Line ("FUCKING CLAUSE FOR COND");
raise Syntax_Error;
end if;
If Get_Last_Cdr(Ptr2) /= Nil_Pointer then
Ada.Text_IO.Put_Line ("FUCKING CDR FOR COND CLAUSE");
raise Syntax_Error;
end if;
if Get_Car(Ptr2) = Interp.Else_Symbol then
-- check <test>. if it's else, it should be in the last clause.
if Is_Cons(Get_Cdr(Ptr1)) then
Ada.Text_IO.Put_Line ("ELSE NOT IN THE LAST COND CLAUSE");
raise Syntax_Error;
end if;
end if;
Ptr1 := Get_Cdr(Ptr1); -- next <clause> list
exit when not Is_Cons(Ptr1);
end loop;
if Ptr1 /= Nil_Pointer then
Ada.Text_IO.Put_Line ("FUCKING LAST CLAUSE FOR COND");
raise Syntax_Error;
end if;
end;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
Switch_Frame (Interp.Stack, Opcode_Evaluate_Object, Get_Car(Get_Car(Operand)), Nil_Pointer); -- <test> in first <clause>
Push_Subframe (Interp, Opcode_Cond_Finish, Operand); -- <clause> list
end Evaluate_Cond_Syntax;
-- ----------------------------------------------------------------
procedure Evaluate_Define_Syntax is
pragma Inline (Evaluate_Define_Syntax);
Synlist: Object_Pointer;
Ptr1: Object_Pointer;
Ptr2: Object_Pointer;
Ptr3: Object_Pointer;
Ptr4: Object_Pointer;
begin
-- TODO: limit the context where define can be used.
-- (define <variable> <expression>)
-- (define (<variable> <formals>) <body>)
-- (define (<variable> . <formal>) <body>)
--
-- e.g)
-- (define x 10)
-- (define (add x y) (+ x y)) -> (define add (lambda (x y) (+ x y)))
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "define"
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
if not Is_Cons(Operand) or else not Is_Cons(Get_Cdr(Operand)) then
-- e.g) (define)
-- (define . 10)
-- (define x . 10)
Ada.Text_IO.Put_LINE ("TOO FEW ARGUMENTS FOR DEFINE");
raise Syntax_Error;
end if;
Ptr1 := Get_Car(Operand);
if Is_Cons(Ptr1) then
-- (define (add x y) ...)
Ptr2 := Get_Car(Ptr1); -- <variable> as a function name
if not Is_Symbol(Ptr2) then
Ada.Text_IO.Put_LINE ("WRONG NAME FOR DEFINE");
raise Syntax_Error;
end if;
Ptr1 := Get_Cdr(Ptr1); -- <formals>
Ptr2 := Ptr1;
while Is_Cons(Ptr2) loop
Ptr3 := Get_Car(Ptr2); -- <formal argument>
if not Is_Symbol(Ptr3) then
Ada.Text_IO.Put_Line ("WRONG FORMAL FOR LAMBDA");
raise Syntax_Error;
end if;
-- Check for a duplication formal argument
-- TODO: make duplication check optional or change the implementation more efficient so that this check is not repeated
Ptr4 := Ptr1;
while Ptr4 /= Ptr2 loop
if Get_Car(Ptr4) = Ptr3 then
Ada.Text_IO.Put_Line ("DUPLICATE FORMAL FOR DEFINE");
raise Syntax_Error;
end if;
Ptr4 := Get_Cdr(Ptr4);
end loop;
-- Move on to the next formal argument
Ptr2 := Get_Cdr(Ptr2);
exit when not Is_Cons(Ptr2);
end loop;
if Ptr2 /= Nil_Pointer and then not Is_Symbol(Ptr2) then
Ada.Text_IO.Put_Line ("FUCKING CDR IN FORMALS FOR DEFINE");
raise Syntax_Error;
end if;
Ptr1 := Get_Cdr(Operand); -- <body>
if not Is_Cons(Ptr1) then
Ada.Text_IO.Put_Line ("NO BODY");
raise Syntax_Error;
end if;
if Get_Last_Cdr(Ptr1) /= Nil_Pointer then
-- (lambda (x y) (+ x y) . 99)
Ada.Text_IO.Put_Line ("FUCKING CDR IN BODY FOR LAMBDA");
raise Syntax_Error;
end if;
elsif Is_Symbol(Ptr1) then
if Get_Cdr(Get_Cdr(Operand)) /= Nil_Pointer then
Ada.Text_IO.Put_LINE ("TOO MANY ARGUMENTS FOR DEFINE");
raise Syntax_Error;
end if;
else
Ada.Text_IO.Put_LINE ("NO SYMBOL NOR ARGUMENT LIST AFTER DEFINE");
raise Syntax_Error;
end if;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
Ptr1 := Get_Car(Operand);
if Is_Cons(Ptr1) then
-- define a function: (define (add x y) ...)
-- Get_Car(Ptr1) -- <variable>
-- Get_Cdr(Ptr1) -- <formals>
-- Get_Cdr(Operand) -- <body>
-- It's ok to not reload but switch because no continuation
-- can be created in this form of 'define'.
Switch_Frame (Interp.Stack, Opcode_Define_Finish, Get_Car(Ptr1), Nil_Pointer);
-- Make closure and set it as a frame result. Note this is done
-- after switching in order to avoid GC problems withoug using
-- Push_Top/Pop_Tops.
Ptr2 := Make_Cons(Interp.Self, Get_Cdr(Ptr1), Get_Cdr(Operand));
Ptr2 := Make_Closure(Interp.Self, Ptr2, Get_Frame_Environment(Interp.Stack));
Set_Frame_Result (Interp.Stack, Ptr2);
else
-- define a symbol: (define x ...)
pragma Assert (Is_Symbol(Ptr1));
-- Arrange to finish defining after value evaluation
-- and to evaluate the value part.
Switch_Frame (Interp.Stack, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Operand)), Nil_Pointer);
Push_Subframe (Interp, Opcode_Define_Finish, Ptr1);
end if;
end Evaluate_Define_Syntax;
-- ----------------------------------------------------------------
procedure Check_Do_Syntax is
Ptr1: Object_Pointer;
Ptr2: Object_Pointer;
Ptr3: Object_Pointer;
begin
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;
end Check_Do_Syntax;
procedure Evaluate_Do_Syntax is
pragma Inline (Evaluate_Do_Syntax);
Synlist: Object_Pointer;
Bindings: aliased Object_Pointer;
Envir: aliased 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> x and sum
-- ((null? x) sum) ; <clause>. if <test> is true, exit do with sum.
-- )
-- )
--
-- (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"
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
Check_Do_Syntax;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
Reload_Frame (Interp, Opcode_Do_Test, Operand);
Envir := Make_Environment(Interp.Self, Get_Frame_Environment(Interp.Stack));
Set_Frame_Environment (Interp.Stack, Envir); -- update the environment
Bindings := Get_Car(Operand); -- <binding> list
if Is_Cons(Bindings) then -- <binding> list
-- <binding> list is not nil.
Push_Top (Interp, Envir'Unchecked_Access);
Push_Top (Interp, Bindings'Unchecked_Access);
Envir := Get_Frame_Environment(Get_Frame_Parent(Interp.Stack));
Push_Frame (Interp, Opcode_Do_Binding, Bindings); -- first <binding>
Push_Frame_With_Environment (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(Bindings))), Envir); -- first <init>
Pop_Tops (Interp, 2);
--else
-- -- <binding> list is nil/empty.
-- -- (do () (#f ... ) ...)
-- Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Car(Get_Cdr(Operand)))); -- <test>
end if;
end Evaluate_Do_Syntax;
-- ----------------------------------------------------------------
procedure Evaluate_If_Syntax is
pragma Inline (Evaluate_If_Syntax);
Synlist: Object_Pointer;
begin
-- (if <test> <consequent>)
-- (if <test> <consequent> <alternate>)
-- e.g) (if (> 3 2) 'yes)
-- (if (> 3 2) 'yes 'no)
-- (if (> 3 2) (- 3 2) (+ 3 2))
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "if".
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
declare
Ptr: Object_Pointer := Operand;
begin
if Not Is_Cons(Ptr) then
-- e.g) (if)
-- (if . 10)
Ada.Text_IO.Put_LINE ("NO CONDITIONAL FOR IF");
raise Syntax_Error;
end if;
Ptr := Get_Cdr(Ptr); -- cons cell containg <consequent>
if not Is_Cons(Ptr) then
Ada.Text_IO.Put_Line ("NO CONSEQUENT FOR IF");
raise Syntax_Error;
end if;
Ptr := Get_Cdr(Ptr); -- cons cell containing <alternate>
if Ptr = Nil_Pointer then
-- no <alternate>. it's ok
null;
elsif not Is_Cons(Ptr) then
-- no <alternate> but reduncant cdr.
-- (if (> 3 2) 3 . 99)
Ada.Text_IO.Put_Line ("FUCKING CDR FOR IF");
raise Syntax_Error;
elsif Get_Cdr(Ptr) /= Nil_Pointer then
-- (if (> 3 2) 3 2 . 99)
-- (if (> 3 2) 3 2 99)
Ada.Text_IO.Put_Line ("TOO MANY ARGUMENTS FOR IF");
raise Syntax_Error;
end if;
end;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
-- Arrange to evaluate <consequent> or <alternate> after <test>
-- evaluation and to evaluate <test>. Use Switch_Frame/Push_Subframe
-- instead of Switch_Frame/Push_Frame for continuation to work.
Switch_Frame (Interp.Stack, Opcode_Evaluate_Object, Get_Car(Operand), Nil_Pointer); -- <test>
Push_Subframe (Interp, Opcode_If_Finish, Get_Cdr(Operand)); -- <consequent> and later
end Evaluate_If_Syntax;
-- ----------------------------------------------------------------
procedure Evaluate_Lambda_Syntax is
pragma Inline (Evaluate_Lambda_Syntax);
Synlist: Object_Pointer;
begin
-- (lambda <formals> <body>)
-- e.g) (lambda (x y) (+ x y))
-- e.g) (lambda (x y . z) z)
-- e.g) (lambda x (car x))
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "lambda". cons cell pointing to <formals>
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
if not Is_Cons(Operand) then
-- e.g) (lambda)
-- (lambda . 10)
Ada.Text_IO.Put_LINE ("FUCKNING CDR FOR LAMBDA");
raise Syntax_Error;
end if;
declare
Ptr1: Object_Pointer;
Ptr2: Object_Pointer;
Ptr3: Object_Pointer;
Ptr4: Object_Pointer;
begin
Ptr1 := Get_Car(Operand); -- <formals>
if Ptr1 = Nil_Pointer or else Is_Symbol(Ptr1) then
-- (lambda () ...) or (lambda x ...)
-- nothing to do
null;
elsif Is_Cons(Ptr1) then
Ptr2 := Ptr1;
loop
Ptr3 := Get_Car(Ptr2); -- <formal argument>
if not Is_Symbol(Ptr3) then
Ada.Text_IO.Put_Line ("WRONG FORMAL FOR LAMBDA");
raise Syntax_Error;
end if;
-- Check for a duplication formal argument
-- TODO: make duplication check optional or change the implementation more efficient so that this check is not repeated
Ptr4 := Ptr1;
while Ptr4 /= Ptr2 loop
if Get_Car(Ptr4) = Ptr3 then
Ada.Text_IO.Put_Line ("DUPLICATE FORMAL FOR LAMBDA");
raise Syntax_Error;
end if;
Ptr4 := Get_Cdr(Ptr4);
end loop;
-- Move on to the next formal argument
Ptr2 := Get_Cdr(Ptr2);
exit when not Is_Cons(Ptr2);
end loop;
if Ptr2 /= Nil_Pointer and then not Is_Symbol(Ptr2) then
Ada.Text_IO.Put_Line ("FUCKING CDR IN FORMALS FOR LAMBDA");
raise Syntax_Error;
end if;
else
Ada.Text_IO.Put_Line ("INVALID FORMALS FOR LAMBDA");
raise Syntax_Error;
end if;
Ptr1 := Get_Cdr(Operand); -- cons cell containing <body>
if not Is_Cons(Ptr1) then
Ada.Text_IO.Put_Line ("NO BODY");
raise Syntax_Error;
end if;
if Get_Last_Cdr(Ptr1) /= Nil_Pointer then
-- (lambda (x y) (+ x y) . 99)
Ada.Text_IO.Put_Line ("FUCKING CDR IN BODY FOR LAMBDA");
raise Syntax_Error;
end if;
end;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
-- Create a closure object and return it the the upper frame.
Return_Frame (Interp, Make_Closure(Interp.Self, Operand, Get_Frame_Environment(Interp.Stack)));
end Evaluate_Lambda_Syntax;
-- ----------------------------------------------------------------
procedure Check_Let_Syntax is
pragma Inline (Check_Let_Syntax);
Bindings: Object_Pointer;
LetBody: Object_Pointer;
begin
-- (let <bindings> <body>)
if not Is_Cons(Operand) then
-- e.g) (let)
-- (let . 10)
Ada.Text_IO.Put_LINE ("FUCKNING CDR FOR LET");
raise Syntax_Error;
end if;
Bindings := Get_Car(Operand); -- <bindings>
if Bindings /= Nil_Pointer and then not Is_Cons(Bindings) then
Ada.Text_IO.Put_Line ("INVALID BINDINGS FOR LET");
raise Syntax_Error;
end if;
Letbody := Get_Cdr(Operand); -- Cons cell to <body>
if not Is_Cons(Letbody) or else Get_Last_Cdr(Letbody) /= Nil_Pointer then
-- (let ((x 2)) )
-- (let ((x 2)) . 99)
-- (let ((x 2)) (+ x 2) . 99)
Ada.Text_IO.Put_Line ("INVALID BODY FOR LET");
raise Syntax_Error;
end if;
if Is_Cons(Bindings) then
declare
Ptr1: Object_Pointer := Bindings;
Ptr2: Object_Pointer;
Ptr3: Object_Pointer;
begin
loop
Ptr2 := Get_Car(Ptr1); -- <binding>
if not Is_Cons(Ptr2) or else not Is_Cons(Get_Cdr(Ptr2)) or else Get_Cdr(Get_Cdr(Ptr2)) /= Nil_Pointer then
-- no binding name or no binding value or garbage after that
Ada.Text_IO.Put_Line ("WRONG BINDING FOR LET");
raise Syntax_Error;
end if;
Ptr2 := Get_Car(Ptr2); -- <binding> name
if not Is_Symbol(Ptr2) then
Ada.Text_IO.Put_Line ("WRONG BINDING NAME FOR LET");
raise Syntax_Error;
end if;
-- Check for a duplicate binding name
-- TODO: make duplication check optional or change the implementation more efficient so that this check is not repeated
Ptr3 := Bindings;
while Ptr3 /= Ptr1 loop
if Get_Car(Get_Car(Ptr3)) = Ptr2 then
Ada.Text_IO.Put_Line ("DUPLICATE BINDING FOR LET");
raise Syntax_Error;
end if;
Ptr3 := Get_Cdr(Ptr3);
end loop;
-- Move on to the next binding
Ptr1 := Get_Cdr(Ptr1);
exit when not Is_Cons(Ptr1);
end loop;
if Ptr1 /= Nil_Pointer then
-- The last cdr is not nil.
Ada.Text_IO.Put_Line ("FUCKING CDR FOR LET BINDING");
raise Syntax_Error;
end if;
end;
end if;
end Check_Let_Syntax;
procedure Evaluate_Let_Syntax is
pragma Inline (Evaluate_Let_Syntax);
Synlist: Object_Pointer;
Envir: aliased Object_Pointer;
Bindings: aliased Object_Pointer;
begin
-- Some let samples:
-- #1.
-- (define x 99) ; define x in the root environment
-- (let () (define x 100)) ; x is defined in the new environment.
-- x ; this must be 99.
--
-- #2.
-- (define x 10) ; x-outer
-- (define y (let ((x (+ x 1))) x)) ; x-inner := x-outer + 1, y := x-inner
-- y ; 11
-- x ; 10
--
-- #3.
-- (define x (let ((x x)) x))
--
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "let".
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
Check_Let_Syntax;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
-- Switch the frame to Opcode_Grouped_Call and let its environment
-- be the new environment created. Use Reload_Frame() instead
-- of Switch_Frame() for continuation. This frame is executed once
-- the Opcode_Let_Binding frame pushed in the 'if' block is finished.
Reload_Frame (Interp, Opcode_Grouped_Call, Get_Cdr(Operand)); -- <body>
-- Create a new environment over the current environment.
Envir := Make_Environment(Interp.Self, Get_Frame_Environment(Interp.Stack));
Set_Frame_Environment (Interp.Stack, Envir); -- update the environment
Bindings := Get_Car(Operand); -- <bindings>
if Bindings /= Nil_Pointer then
-- <bindings> is not empty
Push_Top (Interp, Envir'Unchecked_Access);
Push_Top (Interp, Bindings'Unchecked_Access);
Envir := Get_Frame_Environment(Get_Frame_Parent(Interp.Stack));
-- Say, <bindings> is ((x 2) (y 2)).
-- Get_Car(Bindings) is (x 2).
-- To get x, Get_Car(Get_Car(Bindings))
-- To get 2, Get_Car(Get_Cdr(Get_Car(Bindings)))
-- Arrange to evaluate the first <binding> expression in the parent environment.
Push_Frame_With_Environment (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(Bindings))), Envir);
-- Arrange to perform actual binding. Pass the <binding> name as an intermediate
-- and the next remaing <binding> list as an operand.
Push_Subframe_With_Environment_And_Intermediate (Interp, Opcode_Let_Binding, Get_Cdr(Bindings), Envir, Get_Car(Get_Car(Bindings)));
Pop_Tops (Interp, 2);
end if;
end Evaluate_Let_Syntax;
procedure Evaluate_Letast_Syntax is
pragma Inline (Evaluate_Letast_Syntax);
Synlist: Object_Pointer;
Envir: aliased Object_Pointer;
Bindings: aliased Object_Pointer;
begin
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "let".
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
Check_Let_Syntax;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
Reload_Frame (Interp, Opcode_Grouped_Call, Get_Cdr(Operand)); -- <body>
-- Create a new environment over the current environment.
Envir := Make_Environment(Interp.Self, Get_Frame_Environment(Interp.Stack));
Set_Frame_Environment (Interp.Stack, Envir); -- update the environment
Bindings := Get_Car(Operand); -- <bindings>
if Bindings /= Nil_Pointer then
-- <bindings> is not empty
Push_Top (Interp, Envir'Unchecked_Access);
Push_Top (Interp, Bindings'Unchecked_Access);
-- Say, <bindings> is ((x 2) (y 2)).
-- Get_Car(Bindings) is (x 2).
-- To get x, Get_Car(Get_Car(Bindings))
-- To get 2, Get_Car(Get_Cdr(Get_Car(Bindings)))
-- Arrange to evaluate the first <binding> expression in the parent environment.
Push_Frame_With_Environment (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(Bindings))), Envir);
-- Arrange to perform actual binding. Pass the <binding> name as an intermediate
-- and the next remaing <binding> list as an operand.
Push_Subframe_With_Environment_And_Intermediate (Interp, Opcode_Letast_Binding, Get_Cdr(Bindings), Envir, Get_Car(Get_Car(Bindings)));
Pop_Tops (Interp, 2);
end if;
end Evaluate_Letast_Syntax;
procedure Evaluate_Letrec_Syntax is
pragma Inline (Evaluate_Letrec_Syntax);
Synlist: Object_Pointer;
Envir: Object_Pointer;
Bindings: aliased Object_Pointer;
begin
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "let".
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
Check_Let_Syntax;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
-- Switch the frame to Opcode_Grouped_Call and let its environment
-- be the new environment created. Use Reload_Frame() instead
-- of Switch_Frame() for continuation. This frame is executed once
-- the Opcode_Letrec_Binding frame pushed in the 'if' block is finished.
Reload_Frame (Interp, Opcode_Grouped_Call, Get_Cdr(Operand)); -- <test>
-- Create a new environment over the current environment.
Envir := Make_Environment(Interp.Self, Get_Frame_Environment(Interp.Stack));
Set_Frame_Environment (Interp.Stack, Envir); -- update the environment
Bindings := Get_Car(Operand); -- <bindings>
if Bindings /= Nil_Pointer then
-- <bindings> is not empty
Push_Top (Interp, Bindings'Unchecked_Access);
-- Say, <bindings> is ((x 2) (y 2)).
-- Get_Car(Bindings) is (x 2).
-- To get x, Get_Car(Get_Car(Bindings))
-- To get 2, Get_Car(Get_Cdr(Get_Car(Bindings)))
-- Arrange to evaluate the first <binding> expression in the parent environment.
Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(Bindings))));
-- Arrange to perform actual binding. Pass the <binding> name as an intermediate
-- and the next remaing <binding> list as an operand.
Push_Subframe_With_Intermediate (Interp, Opcode_Letrec_Binding, Get_Cdr(Bindings), Get_Car(Get_Car(Bindings)));
Pop_Tops (Interp, 1);
end if;
end Evaluate_Letrec_Syntax;
-- ----------------------------------------------------------------
procedure Evaluate_Quasiquote_Syntax is
pragma Inline (Evaluate_Quasiquote_Syntax);
begin
Ada.Text_IO.Put_LINE ("UNIMPLEMENTED");
raise Evaluation_Error;
end Evaluate_Quasiquote_Syntax;
-- ----------------------------------------------------------------
procedure Evaluate_Quote_Syntax is
pragma Inline (Evaluate_Quote_Syntax);
Synlist: Object_Pointer;
begin
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "quote". Get the first argument.
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
if not Is_Cons(Operand) then
-- e.g) (quote)
-- (quote . 10)
Ada.Text_IO.Put_LINE ("TOO FEW ARGUMETNS FOR QUOTE");
raise Syntax_Error;
elsif Get_Cdr(Operand) /= Nil_Pointer then
Ada.Text_IO.Put_LINE ("TOO MANY ARGUMENTS FOR QUOTE");
raise Syntax_Error;
end if;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
Return_Frame (Interp, Get_Car(Operand));
end Evaluate_Quote_Syntax;
-- ----------------------------------------------------------------
procedure Evaluate_Set_Syntax is
pragma Inline (Evaluate_Set_Syntax);
Synlist: Object_Pointer;
begin
-- (set! <variable> <expression>)
-- e.g) (set! x 10)
Synlist := Operand;
Operand := Get_Cdr(Operand); -- Skip "set!"
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Synlist.Flags and Syntax_Checked) = 0 then
if not Is_Cons(Operand) or else not Is_Cons(Get_Cdr(Operand)) then
-- e.g) (set!)
-- (set . 10)
-- (set x . 10)
Ada.Text_IO.Put_LINE ("TOO FEW ARGUMENTS FOR SET!");
raise Syntax_Error;
end if;
if not Is_Symbol(Get_Car(Operand)) then -- <variable>
Ada.Text_IO.Put_LINE ("INVALID SYMBOL AFTER SET!");
raise Syntax_Error;
end if;
if Get_Cdr(Get_Cdr(Operand)) /= Nil_Pointer then
-- (set x 10 20)
-- (set x 10 . 20)
Ada.Text_IO.Put_LINE ("TOO MANY ARGUMENTS FOR SET!");
raise Syntax_Error;
end if;
Synlist.Flags := Synlist.Flags or Syntax_Checked;
end if;
Switch_Frame (Interp.Stack, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Operand)), Nil_Pointer); -- <expression>
Push_Subframe (Interp, Opcode_Set_Finish, Get_Car(Operand)); -- <variable>
end Evaluate_Set_Syntax;
-- ----------------------------------------------------------------
procedure Evaluate_List is
Ptr: Object_Pointer;
begin
Ptr := Get_Car(Operand);
if Is_Syntax(Ptr) then
-- special syntax symbol. normal evaluation rule doesn't
-- apply for special syntax objects.
case Ptr.Scode is
when And_Syntax =>
Evaluate_And_Syntax;
when Begin_Syntax =>
Evaluate_Begin_Syntax;
when Case_Syntax =>
Evaluate_Case_Syntax;
when Cond_Syntax =>
Evaluate_Cond_Syntax;
when Define_Syntax =>
Evaluate_Define_Syntax;
when Do_Syntax =>
Evaluate_Do_Syntax;
when If_Syntax =>
Evaluate_If_Syntax;
when Lambda_Syntax =>
Evaluate_Lambda_Syntax;
when Let_Syntax =>
Evaluate_Let_Syntax;
when Letast_Syntax =>
Evaluate_Letast_Syntax;
when Letrec_Syntax =>
Evaluate_Letrec_Syntax;
when Or_Syntax =>
Evaluate_Or_Syntax;
when Quasiquote_Syntax =>
Evaluate_Quasiquote_Syntax;
when Quote_Syntax =>
Evaluate_Quote_Syntax;
when Set_Syntax => -- set!
Evaluate_Set_Syntax;
end case;
else
-- procedure call
-- (<operator> <operand1> ...)
if (Interp.State and Force_Syntax_Check) /= 0 or else
(Operand.Flags and Syntax_Checked) = 0 then
if Get_Last_Cdr(Operand) /= Nil_Pointer then
Ada.Text_IO.Put_Line ("ERROR: FUCKING CDR FOR PROCEDURE CALL.$$$$");
raise Syntax_Error;
end if;
Operand.Flags := Operand.Flags or Syntax_Checked;
end if;
-- Switch the current frame to evaluate <operator>
Switch_Frame (Interp.Stack, Opcode_Evaluate_Object, Ptr, Nil_Pointer);
-- Push a new frame to evaluate arguments.
Push_Subframe (Interp, Opcode_Procedure_Call, Get_Cdr(Operand));
end if;
end Evaluate_List;
begin
Push_Top (Interp, Operand'Unchecked_Access);
Operand := Get_Frame_Operand(Interp.Stack);
declare
f: object_word;
for f'address use interp.stack'address;
o: object_word;
for o'address use operand'address;
begin
ada.text_io.put ("Frame" & object_word'image(f) & " EVALUATE OPERAND" & object_word'image(o) & " ");
print (interp, operand);
ada.text_io.put (" CURRENT RESULT ");
print (interp, get_Frame_result(interp.stack));
end;
if not Is_Normal_Pointer(Operand) then
-- integer, character, specal pointers
-- TODO: some normal pointers may point to literal objects. e.g.) bignum
goto Literal;
end if;
case Operand.Tag is
when Symbol_Object => -- Is_Symbol(Operand)
-- TODO: find it in the Environment hierarchy.. not in the current environemnt.
declare
Ptr: Object_Pointer;
begin
Ptr := Get_Environment (Interp.Self, Operand);
if Ptr = null then
-- unbound
Ada.Text_IO.Put_Line ("Unbound symbol....");
Print (Interp, Operand);
raise Evaluation_Error;
else
-- symbol found in the environment
Operand := Ptr;
goto Literal; -- In fact, this is not a literal, but can be handled in the same way
end if;
end;
when Cons_Object => -- Is_Cons(Operand)
-- ( ... )
Evaluate_List;
when others =>
-- normal literal object
goto Literal;
end case;
goto Done;
<<Literal>>
Return_Frame (Interp, Operand);
goto Done;
<<Done>>
Pop_Tops (Interp, 1);
end Evaluate;