stack.h File Reference

#include "consspaceobject.h"
#include "conspage.h"

Include dependency graph for stack.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	stackframep(vso)   (((struct vector_space_object *)vso)->header.tag.value == STACKFRAMETV)
	is this vector-space object a stack frame?
#define	STACKFRAMETAG   "STAK"
	stack.h
#define	STACKFRAMETV   1262572627

Functions
void	dump_frame (URL_FILE *output, struct cons_pointer pointer)
	Dump a stackframe to this stream for debugging.
void	dump_stack_trace (URL_FILE *output, struct cons_pointer frame_pointer)
struct cons_pointer	fetch_arg (struct stack_frame *frame, unsigned int n)
	Fetch a pointer to the value of the local variable at this index.
void	free_stack_frame (struct stack_frame *frame)
	Free this stack frame.
struct stack_frame *	get_stack_frame (struct cons_pointer pointer)
	get the actual stackframe object from this pointer, or NULL if pointer is not a stackframe pointer.
struct cons_pointer	make_empty_frame (struct cons_pointer previous)
	Make an empty stack frame, and return it.
struct cons_pointer	make_special_frame (struct cons_pointer previous, struct cons_pointer args, struct cons_pointer env)
	A 'special' frame is exactly like a normal stack frame except that the arguments are unevaluated.
struct cons_pointer	make_stack_frame (struct cons_pointer previous, struct cons_pointer args, struct cons_pointer env)
	Allocate a new stack frame with its previous pointer set to this value, its arguments set up from these args, evaluated in this env.
void	set_reg (struct stack_frame *frame, int reg, struct cons_pointer value)
	set a register in a stack frame.

Macro Definition Documentation

stackframep

#define stackframep

(

vso

)

(((struct vector_space_object *)vso)->header.tag.value == STACKFRAMETV)

is this vector-space object a stack frame?

Definition at line 36 of file stack.h.

STACKFRAMETAG

#define STACKFRAMETAG   "STAK"

stack.h

The Lisp evaluation stack.

Stack frames could be implemented in cons space; indeed, the stack could simply be an assoc list consed onto the front of the environment. But such a stack would be costly to search. The design sketched here, with stack frames as special objects, SHOULD be substantially more efficient, but does imply we need to generalise the idea of cons pages with freelists to a more general 'equal sized object pages', so that allocating/freeing stack frames can be more efficient.

Stack frames are not yet a first class object; they have no VECP pointer in cons space.

(c) 2017 Simon Brooke simon.nosp@m.@jou.nosp@m.rneym.nosp@m.an.c.nosp@m.c Licensed under GPL version 2.0, or, at your option, any later version. macros for the tag of a stack frame.

Definition at line 30 of file stack.h.

STACKFRAMETV

#define STACKFRAMETV   1262572627

Definition at line 31 of file stack.h.

Function Documentation

dump_frame()

void dump_frame	(	URL_FILE *	output,
		struct cons_pointer	frame_pointer
	)

Dump a stackframe to this stream for debugging.

Parameters

output	the stream
frame_pointer	the pointer to the frame

Definition at line 244 of file stack.c.

References stack_frame::arg, stack_frame::args, cons_space_object::count, get_stack_frame(), stack_frame::more, nilp, pointer2cell, print(), cons_space_object::tag, url_fputws, and url_fwprintf.

Referenced by dump_object(), and dump_stack_trace().

dump_stack_trace()

void dump_stack_trace	(	URL_FILE *	output,
		struct cons_pointer	frame_pointer
	)

Definition at line 268 of file stack.c.

References dump_frame(), dump_stack_trace(), exceptionp, get_stack_frame(), cons_space_object::payload, pointer2cell, pointer_to_vso, stack_frame::previous, print(), stackframep, url_fputws, and vectorpointp.

Referenced by dump_object(), dump_stack_trace(), and print().

fetch_arg()

struct cons_pointer fetch_arg	(	struct stack_frame *	frame,
		unsigned int	n
	)

Fetch a pointer to the value of the local variable at this index.

Definition at line 286 of file stack.c.

References args_in_frame, NIL, and pointer2cell.

Referenced by lisp_append(), lisp_let(), and lisp_list().

free_stack_frame()

void free_stack_frame

(

struct stack_frame *

frame

)

Free this stack frame.

Definition at line 224 of file stack.c.

References stack_frame::arg, args_in_frame, DEBUG_ALLOC, debug_print(), dec_ref(), stack_frame::more, and nilp.

Referenced by free_vso().

get_stack_frame()

struct stack_frame * get_stack_frame

(

struct cons_pointer

pointer

)

get the actual stackframe object from this pointer, or NULL if pointer is not a stackframe pointer.

Definition at line 53 of file stack.c.

References debug_print(), debug_printf(), DEBUG_STACK, vector_space_object::payload, pointer2cell, stackframep, and vectorpointp.

Referenced by c_apply(), dump_frame(), dump_stack_trace(), eval_form(), free_vso(), lisp_repl(), make_empty_frame(), make_special_frame(), make_stack_frame(), and repl().

make_empty_frame()

struct cons_pointer make_empty_frame

(

struct cons_pointer

previous

)

Make an empty stack frame, and return it.

Parameters

previous	the current top-of-stack;
env	the environment in which evaluation happens.

Returns

the new frame, or NULL if memory is exhausted.

Definition at line 75 of file stack.c.

References stack_frame::arg, stack_frame::args, args_in_frame, DEBUG_ALLOC, debug_dump_object(), debug_print(), stack_frame::function, get_stack_frame(), make_vso(), stack_frame::more, NIL, nilp, stack_frame::previous, and STACKFRAMETV.

Referenced by eval_form(), make_special_frame(), and make_stack_frame().

make_special_frame()

struct cons_pointer make_special_frame	(	struct cons_pointer	previous,
		struct cons_pointer	args,
		struct cons_pointer	env
	)

A 'special' frame is exactly like a normal stack frame except that the arguments are unevaluated.

Parameters

previous	the previous stack frame;
args	a list of the arguments to be stored in this stack frame;
env	the execution environment;

Returns

a new special frame.

Definition at line 183 of file stack.c.

References stack_frame::args, args_in_frame, c_string_to_lisp_string(), consp, debug_dump_object(), debug_print(), DEBUG_STACK, exceptionp, get_stack_frame(), inc_ref(), make_empty_frame(), make_exception(), stack_frame::more, nilp, cons_space_object::payload, pointer2cell, and set_reg().

Referenced by c_apply().

make_stack_frame()

struct cons_pointer make_stack_frame	(	struct cons_pointer	previous,
		struct cons_pointer	args,
		struct cons_pointer	env
	)

Allocate a new stack frame with its previous pointer set to this value, its arguments set up from these args, evaluated in this env.

Parameters

previous	the current top-of-stack; @args the arguments to load into this frame;
env	the environment in which evaluation happens.

Returns

the new frame, or an exception if one occurred while building it.

Definition at line 116 of file stack.c.

References stack_frame::args, args_in_frame, c_string_to_lisp_string(), consp, debug_dump_object(), debug_print(), debug_print_object(), debug_printf(), DEBUG_STACK, eval_form(), eval_forms(), exceptionp, get_stack_frame(), inc_ref(), make_empty_frame(), make_exception(), stack_frame::more, nilp, cons_space_object::payload, pointer2cell, and set_reg().

Referenced by c_apply(), and repl().

set_reg()

void set_reg	(	struct stack_frame *	frame,
		int	reg,
		struct cons_pointer	value
	)

set a register in a stack frame.

Alwaye use this to do so, because that way we can be sure the inc_ref happens!

Definition at line 33 of file stack.c.

References stack_frame::arg, stack_frame::args, debug_print_object(), debug_printf(), debug_println(), DEBUG_STACK, dec_ref(), and inc_ref().

Referenced by eval_form(), lisp_apply(), make_special_frame(), and make_stack_frame().