SchemeContinuation Class Reference

#include <schcont.hpp>

Inheritance diagram for SchemeContinuation:

[legend]Collaboration diagram for SchemeContinuation:

[legend]List of all members.

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Detailed Description

Scheme-specific continuation-based virtual machine.

This class determines the Scheme computation model providing the method JustEvaluate() and overriding the method CustomCommand() so that it handles to instruction codes missing in the base class. The specific context handling is also provided.

Definition at line 104 of file schcont.hpp.

Public Types
enum	CustomInstructions { case_check = max_command - 1 }
	additional instructions More...
enum	Instructions {   just_evaluate = -1, evaluate_prepared = -2, evaluate_progn = -3, quote_parameter = -4,   drop_result = -5, return_unspecified = -6, end_of_clauses = -7, cond_clause = -8,   bail_on_false = -9, set_context = -10, assign_to = -11, assign_location = -12,   generic_iteration = -13, iteration_callback = -14, max_command = -14 }
	The instruction set of the machine. More...
Public Member Functions
	SchemeContinuation ()
	The default constructor.
	SchemeContinuation (const SchemeContinuation &other, bool b)
	The CALL/CC-related constructor.
	~SchemeContinuation ()
	The destructor.
SchContextRef	GetContext () const
	Get the current context.
void	SetContext (const SchContextRef &context)
	Set the current context.
bool	Step ()
	Perform a single step of the evaluation.
int	GetMark () const
	Mark the todo stack before starting an evaluation.
bool	Ready (int mark=0) const
	Is the evaluation complete?
SReference	Get ()
	Get the result of the evaluation.
void	ReplaceContinuation (const IntelibContinuation &other)
	Replace the entire state of the continuation.
void	PushTodo (int opcode, const SReference &param)
	Add an instruction to the todo stack.
void	PushTodo (int opcode)
	Add a parameterless instruction to the todo stack.
bool	PopTodo (int &opcode, SReference &param)
	Get (and remove) the top of the todo stack.
void	PushResult (const SReference &param)
	Put item into the result stack.
bool	PopResult (SReference &param)
	Get (and remove) the item from top of the result stack.
void	RegularReturn (const SReference &ref)
	Return a value from a Lisp function.
void	ReferenceReturn (SReference &ref, const SReference &superstruct)
	Return an assignable reference from a Lisp function.
void	AgentReturn (const SReference &val, const SExpressionSetfAgent *ag)
	Return a Setf Agent from a Lisp function.
void	TailReturn (const SReference &ref)
	Return a tail (to be evaluated) from a Lisp function.
void	ReturnUnspecified ()
	Return the 'unspecified' value from a Lisp function.
void	SetContext (const SReference &cont)
	Set current lexical context.
Static Public Member Functions
static void	InterruptEvaluator ()
	Interrupt the evaluation.
static void	RemoveInterruption ()
	Cances the interruption of the evaluation.
static void	SuspendInterruptions ()
	Temporaryly disallow interruptions.
static void	ResumeInterruptions ()
	Allow interruptions again.
Protected Member Functions
void	PlaceFormToStack (const SExpressionCons *form, int len)
	Place a prepared form to the stack.
Protected Attributes
SReference *	PTheFalseValue

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Member Enumeration Documentation

enum SchemeContinuation::CustomInstructions

additional instructions Enumeration values: case_check  Definition at line 119 of file schcont.hpp.

enum IntelibContinuation::Instructions [inherited]

The instruction set of the machine. Zero and positive opcodes stand for "call a function with that many args", in which case the function object and the args are taken from the result stack. The numbers from -1 downto max_command are the special operation codes. The numbers below max_command are for the operations added by subclasses (e.g., Scheme-specific and Lisp-specific instructions). Enumeration values: just_evaluate  Just evaluate the param. evaluate_prepared  Evaluate a form in which all params are already computed. evaluate_progn  Evaluate a list of forms, one by one. quote_parameter  Just put the parameter into the result stack. drop_result  Remove one item from the result stack thus dropping it. return_unspecified  Return the value which stands for 'unspecified result'. end_of_clauses  No-op, used as a label for cond_clause and bail_on_false. cond_clause  A conditional clause. Take the value on top of the result stack. If it is true, then remove all the stuff from the todo stack until the end_of_clauses mark, and then add the param as progn to todo. Otherwise (that is, the condition value was false), just do nothing. bail_on_false  Check and jump on false. Take the value on top of the result stack. If it is false, then remove all the stuff from the todo stack until the end_of_clauses mark, and then return the false value back to stack. Otherwise, just do nothing set_context  Set the current context to the param. Note: PushTodo() never adds another set_context if the top of the todo stack contains set_context assign_to  Assign to the given location. Warning: param MUST be SExpressionLocation assign_location  Assign to a location taken from result stack. The top of the result stack should contain either a SExpressionLocation or a SExpressionSetfAgent generic_iteration  Generic iteration. See SExpressionGenericIteration iteration_callback  Generic iteration implementation subcommand. max_command  -max_command is the count of defined commands Definition at line 201 of file conteval.hpp.

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Constructor & Destructor Documentation

SchemeContinuation::SchemeContinuation (   )

The default constructor. Definition at line 107 of file schcont.hpp. References PTheSchemeBooleanFalse.

SchemeContinuation::SchemeContinuation (  const SchemeContinuation &  other, bool  b )

The CALL/CC-related constructor. Definition at line 111 of file schcont.hpp. References PTheSchemeBooleanFalse.

SchemeContinuation::~SchemeContinuation (   )

The destructor. Definition at line 116 of file schcont.hpp.

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Member Function Documentation

SchContextRef SchemeContinuation::GetContext (   )  const

Get the current context. Reimplemented from IntelibContinuation. Definition at line 122 of file schcont.hpp. References IntelibContinuation::GetContext().

void SchemeContinuation::SetContext (  const SchContextRef &  context  )

Set the current context. Definition at line 126 of file schcont.hpp. References IntelibContinuation::SetContext().

bool IntelibContinuation::Step (   )  [inherited]

Perform a single step of the evaluation. Returns false in case the todo stack is empty Note: This function must never be reentered, otherwise CALL/CC won't work for obvious reasons. Should you decide to work your own evaluation-based machine, make sure you never call evaluator from within itself. Definition at line 105 of file conteval.cpp. References IntelibContinuation::assign_location, IntelibContinuation::assign_to, IntelibContinuation::bail_on_false, IntelibContinuation::cond_clause, IntelibContinuation::CustomCommand(), IntelibContinuation::drop_result, IntelibContinuation::end_of_clauses, IntelibContinuation::evaluate_prepared, IntelibContinuation::evaluate_progn, IntelibContinuation::generic_iteration, SReference::GetPtr(), IntelibContinuation::iteration_callback, IntelibContinuation::just_evaluate, IntelibContinuation::JustEvaluate(), IntelibContinuation::PopResult(), IntelibContinuation::PopTodo(), PTheEmptyList, IntelibContinuation::PushResult(), IntelibContinuation::quote_parameter, IntelibContinuation::return_unspecified, IntelibContinuation::ReturnUnspecified(), and IntelibContinuation::set_context.

int IntelibContinuation::GetMark (   )  const [inherited]

Mark the todo stack before starting an evaluation. Definition at line 168 of file conteval.hpp.

bool IntelibContinuation::Ready (  int  mark = 0  )  const [inherited]

Is the evaluation complete? Parameters: mark  is the optional mark returned by the GetMark() method. This is to be used when you wish to evaluate an expression within the existing machine Definition at line 175 of file conteval.hpp.

SReference IntelibContinuation::Get (   )  [inherited]

Get the result of the evaluation. Definition at line 96 of file conteval.cpp.

void IntelibContinuation::ReplaceContinuation (  const IntelibContinuation &  other  )  [inherited]

Replace the entire state of the continuation. This is how the CALL/CC feature works. Parameters: other  should be an object made with the 2-ary constructor. Definition at line 70 of file conteval.cpp.

void IntelibContinuation::PushTodo (  int  opcode, const SReference &  param )  [inherited]

Add an instruction to the todo stack. Parameters: opcode  is the instruction code, see the Instructions enum for explanation param  is the instruction parameter Definition at line 199 of file conteval.cpp. References IntelibContinuation::set_context. Referenced by IntelibContinuation::PlaceFormToStack(), IntelibContinuation::PushTodo(), and IntelibContinuation::TailReturn().

void IntelibContinuation::PushTodo (  int  opcode  )  [inherited]

Add a parameterless instruction to the todo stack. Parameters: opcode  is the instruction code, see the Instructions enum for explanation Definition at line 229 of file conteval.cpp. References IntelibContinuation::PushTodo().

bool IntelibContinuation::PopTodo (  int &  opcode, SReference &  param )  [inherited]

Get (and remove) the top of the todo stack. Warning: you shouldn't ever want to use this method Definition at line 235 of file conteval.cpp. Referenced by IntelibContinuation::Step().

void IntelibContinuation::PushResult (  const SReference &  param  )  [inherited]

Put item into the result stack. Definition at line 249 of file conteval.cpp. Referenced by IntelibContinuation::AgentReturn(), IntelibContinuation::ReferenceReturn(), IntelibContinuation::RegularReturn(), and IntelibContinuation::Step().

bool IntelibContinuation::PopResult (  SReference &  param  )  [inherited]

Get (and remove) the item from top of the result stack. Definition at line 264 of file conteval.cpp. Referenced by IntelibContinuation::Step().

void IntelibContinuation::RegularReturn (  const SReference &  ref  )  [inherited]

Return a value from a Lisp function. Definition at line 273 of file conteval.cpp. References IntelibContinuation::PushResult(). Referenced by IntelibContinuation::ReturnUnspecified().

void IntelibContinuation::ReferenceReturn (  SReference &  ref, const SReference &  superstruct )  [inherited]

Return an assignable reference from a Lisp function. Definition at line 290 of file conteval.cpp. References IntelibContinuation::PushResult().

void IntelibContinuation::AgentReturn (  const SReference &  val, const SExpressionSetfAgent *  ag )  [inherited]

Return a Setf Agent from a Lisp function. Definition at line 300 of file conteval.cpp. References IntelibContinuation::PushResult().

void IntelibContinuation::TailReturn (  const SReference &  ref  )  [inherited]

Return a tail (to be evaluated) from a Lisp function. Definition at line 310 of file conteval.cpp. References IntelibContinuation::just_evaluate, and IntelibContinuation::PushTodo().

void IntelibContinuation::ReturnUnspecified (   )  [inherited]

Return the 'unspecified' value from a Lisp function. Definition at line 315 of file conteval.cpp. References IntelibContinuation::RegularReturn(). Referenced by IntelibContinuation::Step().

void IntelibContinuation::SetContext (  const SReference &  cont  )  [inherited]

Set current lexical context. Definition at line 288 of file conteval.hpp. Referenced by SetContext(), and LispContinuation::SetContext().

static void IntelibContinuation::InterruptEvaluator (   )  [static, inherited]

Interrupt the evaluation. Definition at line 296 of file conteval.hpp.

static void IntelibContinuation::RemoveInterruption (   )  [static, inherited]

Cances the interruption of the evaluation. Definition at line 298 of file conteval.hpp.

static void IntelibContinuation::SuspendInterruptions (   )  [static, inherited]

Temporaryly disallow interruptions. Definition at line 300 of file conteval.hpp.

static void IntelibContinuation::ResumeInterruptions (   )  [static, inherited]

Allow interruptions again. Definition at line 302 of file conteval.hpp.

void IntelibContinuation::PlaceFormToStack (  const SExpressionCons *  form, int  len )  [protected, inherited]

Place a prepared form to the stack. Parameters: form  is the list len  is the count of already-pushed elements e.g. if you have already passed the function and form is only the list of parameters, use 1. If the list contains the function as well, use 0 Definition at line 452 of file conteval.cpp. References IntelibContinuation::just_evaluate, and IntelibContinuation::PushTodo().

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Member Data Documentation

SReference* IntelibContinuation::PTheFalseValue [protected, inherited]

Definition at line 134 of file conteval.hpp.

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The documentation for this class was generated from the following files:

• schcont.hpp
• schcont.cpp

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