require "python-semantics-literals.k"

require "python-semantics-try.k"

module PYTHON-SEMANTICS-ITERATORS

imports PYTHON-SEMANTICS-LITERALS

imports PYTHON-SEMANTICS-TRY

rule invokeBuiltin("tuple.__iter__",_) => return valueIterator(String2Id("self"))

rule invokeBuiltin("list.__iter__",_) => return valueIterator(String2Id("self"))

rule invokeBuiltin("iterator.__iter__",_) => return String2Id("self")

rule <k> invokeBuiltin("iterator.__next__", "self" |-> obj(Self,_)) => return B ...</k>

<object>...

<id>Self</id>

<oattrs>... "__value__" |-> list((ListItem(B) => .) L:List) ...</oattrs>

...</object>

rule <k> invokeBuiltin("iterator.__next__", "self" |-> obj(Self,_)) => raise ref("StopIteration") ...</k>

<object>...

<id>Self</id>

<oattrs>... "__value__" |-> list(.) ...</oattrs>

...</object>

//rule <k> invokeBuiltin(obj("iter_next",_), ListItem(obj(B,_)), .) => try: (getmember(B2, "__getitem__", true, false, true) (I:Int)) except ref("IndexError"): (setx(.Obj) ~> raise ref("StopIteration")) else: pass ...</k>

// <object>...

// <id>B</id>

// <oattrs>... "__index__" |-> (I => I +Int 1) "__value__" |-> B2 ...</oattrs>

// ...</object>

rule invokeBuiltin("iter",_) => (if hasmember(String2Id("object"), "__iter__") :

String2Id("object"), .Expressions := getmember(String2Id("object"), "__iter__", true, false, true) (.Arguments)

else:

if hasmember(String2Id("object"), "__getitem__") :

String2Id("object"), .Expressions := getitemIterator(String2Id("object"))

else:

raiseInternal("TypeError", "object is not iterable")) newline

if hasmember(String2Id("object"), "__next__"):

return String2Id("object")

else:

raiseInternal("TypeError", "iter() returned non-iterator")

//TODO: sentinels

syntax Expression ::= getitemIterator(Expression) [strict]

rule getitemIterator(O:Object) => mutable("__index__" |-> 0 "__value__" |-> ref(id(O)), ref("iterator"))

syntax Expression ::= valueIterator(Expression) [strict]

rule valueIterator(O:Object) => mutable(getattr(O, "__value__"), ref("iterator"))

endmodule