From e600fc409c577eec02af612a36431c477a9c875e Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Fri, 18 Nov 2016 19:04:05 -0800 Subject: [PATCH] altos/lisp: Add continuations This provides call/cc and makes 'stacks' visible to the application. Signed-off-by: Keith Packard --- src/lisp/Makefile | 1 + src/lisp/ao_lisp.h | 77 ++++++++-- src/lisp/ao_lisp_builtin.c | 6 +- src/lisp/ao_lisp_error.c | 82 ++++------ src/lisp/ao_lisp_eval.c | 151 +++--------------- src/lisp/ao_lisp_frame.c | 44 +++--- src/lisp/ao_lisp_lambda.c | 3 +- src/lisp/ao_lisp_make_const.c | 3 +- src/lisp/ao_lisp_mem.c | 28 ++++ src/lisp/ao_lisp_poly.c | 4 + src/lisp/ao_lisp_stack.c | 279 ++++++++++++++++++++++++++++++++++ 11 files changed, 461 insertions(+), 217 deletions(-) create mode 100644 src/lisp/ao_lisp_stack.c diff --git a/src/lisp/Makefile b/src/lisp/Makefile index 15297999..dd5a0cb4 100644 --- a/src/lisp/Makefile +++ b/src/lisp/Makefile @@ -21,6 +21,7 @@ SRCS=\ ao_lisp_eval.c \ ao_lisp_rep.c \ ao_lisp_save.c \ + ao_lisp_stack.c \ ao_lisp_error.c OBJS=$(SRCS:.c=.o) diff --git a/src/lisp/ao_lisp.h b/src/lisp/ao_lisp.h index bcefbabf..a8e1715a 100644 --- a/src/lisp/ao_lisp.h +++ b/src/lisp/ao_lisp.h @@ -75,6 +75,7 @@ extern uint8_t ao_lisp_const[AO_LISP_POOL_CONST]; #define _ao_lisp_atom_eof _atom("eof") #define _ao_lisp_atom_save _atom("save") #define _ao_lisp_atom_restore _atom("restore") +#define _ao_lisp_atom_call2fcc _atom("call/cc") #else #include "ao_lisp_const.h" #ifndef AO_LISP_POOL @@ -99,7 +100,11 @@ extern uint8_t ao_lisp_pool[AO_LISP_POOL + AO_LISP_POOL_EXTRA]; #define AO_LISP_BUILTIN 5 #define AO_LISP_FRAME 6 #define AO_LISP_LAMBDA 7 -#define AO_LISP_NUM_TYPE 8 +#define AO_LISP_STACK 8 +#define AO_LISP_NUM_TYPE 9 + +/* Leave two bits for types to use as they please */ +#define AO_LISP_OTHER_TYPE_MASK 0x3f #define AO_LISP_NIL 0 @@ -153,22 +158,17 @@ struct ao_lisp_val { struct ao_lisp_frame { uint8_t type; - uint8_t _num; + uint8_t num; ao_poly prev; struct ao_lisp_val vals[]; }; -#define AO_LISP_FRAME_NUM_MASK 0x7f - -/* Set when the frame escapes the lambda */ +/* Set on type when the frame escapes the lambda */ #define AO_LISP_FRAME_MARK 0x80 - -static inline int ao_lisp_frame_num(struct ao_lisp_frame *f) { - return f->_num & AO_LISP_FRAME_NUM_MASK; -} +#define AO_LISP_FRAME_PRINT 0x40 static inline int ao_lisp_frame_marked(struct ao_lisp_frame *f) { - return f->_num & AO_LISP_FRAME_MARK; + return f->type & AO_LISP_FRAME_MARK; } static inline struct ao_lisp_frame * @@ -195,6 +195,7 @@ enum eval_state { }; struct ao_lisp_stack { + uint8_t type; /* AO_LISP_STACK */ uint8_t state; /* enum eval_state */ ao_poly prev; /* previous stack frame */ ao_poly sexprs; /* expressions to evaluate */ @@ -204,6 +205,17 @@ struct ao_lisp_stack { ao_poly list; /* most recent function call */ }; +#define AO_LISP_STACK_MARK 0x80 /* set on type when a reference has been taken */ +#define AO_LISP_STACK_PRINT 0x40 /* stack is being printed */ + +static inline int ao_lisp_stack_marked(struct ao_lisp_stack *s) { + return s->type & AO_LISP_STACK_MARK; +} + +static inline void ao_lisp_stack_mark(struct ao_lisp_stack *s) { + s->type |= AO_LISP_STACK_MARK; +} + static inline struct ao_lisp_stack * ao_lisp_poly_stack(ao_poly p) { @@ -216,8 +228,6 @@ ao_lisp_stack_poly(struct ao_lisp_stack *stack) return ao_lisp_poly(stack, AO_LISP_OTHER); } -extern struct ao_lisp_stack *ao_lisp_stack; -extern struct ao_lisp_stack *ao_lisp_stack_free_list; extern ao_poly ao_lisp_v; #define AO_LISP_FUNC_LAMBDA 0 @@ -276,6 +286,7 @@ enum ao_lisp_builtin_id { builtin_led, builtin_save, builtin_restore, + builtin_call_cc, _builtin_last }; @@ -315,7 +326,7 @@ ao_lisp_poly_other(ao_poly poly) { static inline uint8_t ao_lisp_other_type(void *other) { - return *((uint8_t *) other); + return *((uint8_t *) other) & AO_LISP_OTHER_TYPE_MASK; } static inline ao_poly @@ -455,6 +466,12 @@ ao_lisp_string_stash(int id, char *string); char * ao_lisp_string_fetch(int id); +void +ao_lisp_stack_stash(int id, struct ao_lisp_stack *stack); + +struct ao_lisp_stack * +ao_lisp_stack_fetch(int id); + void ao_lisp_poly_stash(int id, ao_poly poly); @@ -617,6 +634,8 @@ ao_lisp_frame_print(ao_poly p); /* lambda */ extern const struct ao_lisp_type ao_lisp_lambda_type; +extern const char *ao_lisp_state_names[]; + struct ao_lisp_lambda * ao_lisp_lambda_new(ao_poly cons); @@ -646,12 +665,40 @@ ao_lisp_save(struct ao_lisp_cons *cons); ao_poly ao_lisp_restore(struct ao_lisp_cons *cons); -/* error */ +/* stack */ extern const struct ao_lisp_type ao_lisp_stack_type; +extern struct ao_lisp_stack *ao_lisp_stack; +extern struct ao_lisp_stack *ao_lisp_stack_free_list; + +void +ao_lisp_stack_reset(struct ao_lisp_stack *stack); + +int +ao_lisp_stack_push(void); + +void +ao_lisp_stack_pop(void); + +void +ao_lisp_stack_clear(void); + +void +ao_lisp_stack_print(ao_poly stack); + +ao_poly +ao_lisp_stack_eval(void); + +ao_poly +ao_lisp_call_cc(struct ao_lisp_cons *cons); + +/* error */ + +void +ao_lisp_error_poly(char *name, ao_poly poly, ao_poly last); void -ao_lisp_stack_print(void); +ao_lisp_error_frame(int indent, char *name, struct ao_lisp_frame *frame); ao_poly ao_lisp_error(int error, char *format, ...); diff --git a/src/lisp/ao_lisp_builtin.c b/src/lisp/ao_lisp_builtin.c index 6cbcb92c..4c845307 100644 --- a/src/lisp/ao_lisp_builtin.c +++ b/src/lisp/ao_lisp_builtin.c @@ -86,6 +86,7 @@ static const ao_poly builtin_names[] = { [builtin_led] = _ao_lisp_atom_led, [builtin_save] = _ao_lisp_atom_save, [builtin_restore] = _ao_lisp_atom_restore, + [builtin_call_cc] = _ao_lisp_atom_call2fcc, }; @@ -117,9 +118,7 @@ void ao_lisp_builtin_print(ao_poly b) { struct ao_lisp_builtin *builtin = ao_lisp_poly_builtin(b); - printf("[builtin %s %s]", - ao_lisp_args_name(builtin->args), - ao_lisp_builtin_name(builtin->func)); + printf("%s", ao_lisp_builtin_name(builtin->func)); } ao_poly @@ -599,5 +598,6 @@ const ao_lisp_func_t ao_lisp_builtins[] = { [builtin_delay] = ao_lisp_delay, [builtin_save] = ao_lisp_save, [builtin_restore] = ao_lisp_restore, + [builtin_call_cc] = ao_lisp_call_cc, }; diff --git a/src/lisp/ao_lisp_error.c b/src/lisp/ao_lisp_error.c index 937739e9..54a9be10 100644 --- a/src/lisp/ao_lisp_error.c +++ b/src/lisp/ao_lisp_error.c @@ -15,23 +15,24 @@ #include "ao_lisp.h" #include -static void -ao_lisp_error_poly(char *name, ao_poly poly) +void +ao_lisp_error_poly(char *name, ao_poly poly, ao_poly last) { int first = 1; printf("\t\t%s(", name); if (ao_lisp_poly_type(poly) == AO_LISP_CONS) { - struct ao_lisp_cons *cons = ao_lisp_poly_cons(poly); - - if (cons) { - while (cons) { + if (poly) { + while (poly) { + struct ao_lisp_cons *cons = ao_lisp_poly_cons(poly); if (!first) printf("\t\t "); else first = 0; ao_lisp_poly_print(cons->car); printf("\n"); - cons = ao_lisp_poly_cons(cons->cdr); + if (poly == last) + break; + poly = cons->cdr; } printf("\t\t )\n"); } else @@ -48,7 +49,7 @@ static void tabs(int indent) printf("\t"); } -static void +void ao_lisp_error_frame(int indent, char *name, struct ao_lisp_frame *frame) { int f; @@ -56,51 +57,30 @@ ao_lisp_error_frame(int indent, char *name, struct ao_lisp_frame *frame) tabs(indent); printf ("%s{", name); if (frame) { - for (f = 0; f < ao_lisp_frame_num(frame); f++) { - if (f != 0) { - tabs(indent); - printf(" "); + if (frame->type & AO_LISP_FRAME_PRINT) + printf("recurse..."); + else { + frame->type |= AO_LISP_FRAME_PRINT; + for (f = 0; f < frame->num; f++) { + if (f != 0) { + tabs(indent); + printf(" "); + } + ao_lisp_poly_print(frame->vals[f].atom); + printf(" = "); + ao_lisp_poly_print(frame->vals[f].val); + printf("\n"); } - ao_lisp_poly_print(frame->vals[f].atom); - printf(" = "); - ao_lisp_poly_print(frame->vals[f].val); - printf("\n"); + if (frame->prev) + ao_lisp_error_frame(indent + 1, "prev: ", ao_lisp_poly_frame(frame->prev)); + frame->type &= ~AO_LISP_FRAME_PRINT; } - if (frame->prev) - ao_lisp_error_frame(indent + 1, "prev: ", ao_lisp_poly_frame(frame->prev)); - } - tabs(indent); - printf(" }\n"); + tabs(indent); + printf(" }\n"); + } else + printf ("}\n"); } -static const char *state_names[] = { - "sexpr", - "val", - "formal", - "exec", - "cond", - "cond_test", - "progn", -}; - -void -ao_lisp_stack_print(void) -{ - struct ao_lisp_stack *s; - printf("Value: "); ao_lisp_poly_print(ao_lisp_v); printf("\n"); - printf("Stack:\n"); - for (s = ao_lisp_stack; s; s = ao_lisp_poly_stack(s->prev)) { - printf("\t[\n"); - printf("\t\texpr: "); ao_lisp_poly_print(s->list); printf("\n"); - printf("\t\tstate: %s\n", state_names[s->state]); -// printf("\t\tmacro: %s\n", s->macro ? "true" : "false"); - ao_lisp_error_poly ("sexprs: ", s->sexprs); - ao_lisp_error_poly ("values: ", s->values); - ao_lisp_error_frame(2, "frame: ", ao_lisp_poly_frame(s->frame)); -// ao_lisp_error_frame(2, "mframe: ", ao_lisp_poly_frame(s->macro_frame)); - printf("\t]\n"); - } -} ao_poly ao_lisp_error(int error, char *format, ...) @@ -112,7 +92,9 @@ ao_lisp_error(int error, char *format, ...) vprintf(format, args); va_end(args); printf("\n"); - ao_lisp_stack_print(); + printf("Value: "); ao_lisp_poly_print(ao_lisp_v); printf("\n"); + printf("Stack:\n"); + ao_lisp_stack_print(ao_lisp_stack_poly(ao_lisp_stack)); printf("Globals:\n\t"); ao_lisp_frame_print(ao_lisp_frame_poly(ao_lisp_frame_global)); printf("\n"); diff --git a/src/lisp/ao_lisp_eval.c b/src/lisp/ao_lisp_eval.c index ef521605..2460a32a 100644 --- a/src/lisp/ao_lisp_eval.c +++ b/src/lisp/ao_lisp_eval.c @@ -16,68 +16,9 @@ #include "ao_lisp.h" #include -const struct ao_lisp_type ao_lisp_stack_type; - -static int -stack_size(void *addr) -{ - (void) addr; - return sizeof (struct ao_lisp_stack); -} - -static void -stack_mark(void *addr) -{ - struct ao_lisp_stack *stack = addr; - for (;;) { - ao_lisp_poly_mark(stack->sexprs, 0); - ao_lisp_poly_mark(stack->values, 0); - /* no need to mark values_tail */ - ao_lisp_poly_mark(stack->frame, 0); - ao_lisp_poly_mark(stack->list, 0); - stack = ao_lisp_poly_stack(stack->prev); - if (ao_lisp_mark_memory(&ao_lisp_stack_type, stack)) - break; - } -} - -static void -stack_move(void *addr) -{ - struct ao_lisp_stack *stack = addr; - - while (stack) { - struct ao_lisp_stack *prev; - int ret; - (void) ao_lisp_poly_move(&stack->sexprs, 0); - (void) ao_lisp_poly_move(&stack->values, 0); - (void) ao_lisp_poly_move(&stack->values_tail, 0); - (void) ao_lisp_poly_move(&stack->frame, 0); - (void) ao_lisp_poly_move(&stack->list, 0); - prev = ao_lisp_poly_stack(stack->prev); - if (!prev) - break; - ret = ao_lisp_move_memory(&ao_lisp_stack_type, (void **) &prev); - if (prev != ao_lisp_poly_stack(stack->prev)) - stack->prev = ao_lisp_stack_poly(prev); - if (ret) - break; - stack = prev; - } -} - -const struct ao_lisp_type ao_lisp_stack_type = { - .size = stack_size, - .mark = stack_mark, - .move = stack_move, - .name = "stack" -}; - struct ao_lisp_stack *ao_lisp_stack; ao_poly ao_lisp_v; -struct ao_lisp_stack *ao_lisp_stack_free_list; - ao_poly ao_lisp_set_cond(struct ao_lisp_cons *c) { @@ -86,72 +27,6 @@ ao_lisp_set_cond(struct ao_lisp_cons *c) return AO_LISP_NIL; } -static void -ao_lisp_stack_reset(struct ao_lisp_stack *stack) -{ - stack->state = eval_sexpr; - stack->sexprs = AO_LISP_NIL; - stack->values = AO_LISP_NIL; - stack->values_tail = AO_LISP_NIL; -} - - -static int -ao_lisp_stack_push(void) -{ - struct ao_lisp_stack *stack; - if (ao_lisp_stack_free_list) { - stack = ao_lisp_stack_free_list; - ao_lisp_stack_free_list = ao_lisp_poly_stack(stack->prev); - } else { - stack = ao_lisp_alloc(sizeof (struct ao_lisp_stack)); - if (!stack) - return 0; - } - stack->prev = ao_lisp_stack_poly(ao_lisp_stack); - stack->frame = ao_lisp_frame_poly(ao_lisp_frame_current); - stack->list = AO_LISP_NIL; - ao_lisp_stack = stack; - ao_lisp_stack_reset(stack); - DBGI("stack push\n"); - DBG_FRAMES(); - DBG_IN(); - return 1; -} - -static void -ao_lisp_stack_pop(void) -{ - ao_poly prev; - struct ao_lisp_frame *prev_frame; - - if (!ao_lisp_stack) - return; - prev = ao_lisp_stack->prev; - ao_lisp_stack->prev = ao_lisp_stack_poly(ao_lisp_stack_free_list); - ao_lisp_stack_free_list = ao_lisp_stack; - - ao_lisp_stack = ao_lisp_poly_stack(prev); - prev_frame = ao_lisp_frame_current; - if (ao_lisp_stack) - ao_lisp_frame_current = ao_lisp_poly_frame(ao_lisp_stack->frame); - else - ao_lisp_frame_current = NULL; - if (ao_lisp_frame_current != prev_frame) - ao_lisp_frame_free(prev_frame); - DBG_OUT(); - DBGI("stack pop\n"); - DBG_FRAMES(); -} - -static void -ao_lisp_stack_clear(void) -{ - ao_lisp_stack = NULL; - ao_lisp_frame_current = NULL; - ao_lisp_v = AO_LISP_NIL; -} - static int func_type(ao_poly func) { @@ -162,6 +37,8 @@ func_type(ao_poly func) return ao_lisp_poly_builtin(func)->args & AO_LISP_FUNC_MASK; case AO_LISP_LAMBDA: return ao_lisp_poly_lambda(func)->args; + case AO_LISP_STACK: + return AO_LISP_FUNC_LAMBDA; default: ao_lisp_error(AO_LISP_INVALID, "not a func"); return -1; @@ -392,10 +269,12 @@ ao_lisp_eval_exec(void) DBGI("set "); DBG_POLY(atom); DBG(" = "); DBG_POLY(val); DBG("\n"); }); builtin = ao_lisp_poly_builtin(ao_lisp_v); - if (builtin->args & AO_LISP_FUNC_FREE_ARGS) + if (builtin->args & AO_LISP_FUNC_FREE_ARGS && !ao_lisp_stack_marked(ao_lisp_stack)) ao_lisp_cons_free(ao_lisp_poly_cons(ao_lisp_stack->values)); ao_lisp_v = v; + ao_lisp_stack->values = AO_LISP_NIL; + ao_lisp_stack->values_tail = AO_LISP_NIL; DBGI(".. result "); DBG_POLY(ao_lisp_v); DBG ("\n"); DBGI(".. frame "); DBG_POLY(ao_lisp_frame_poly(ao_lisp_frame_current)); DBG("\n"); break; @@ -404,12 +283,18 @@ ao_lisp_eval_exec(void) ao_lisp_stack->state = eval_progn; v = ao_lisp_lambda_eval(); ao_lisp_stack->sexprs = v; + ao_lisp_stack->values = AO_LISP_NIL; + ao_lisp_stack->values_tail = AO_LISP_NIL; DBGI(".. sexprs "); DBG_POLY(ao_lisp_stack->sexprs); DBG("\n"); DBGI(".. frame "); DBG_POLY(ao_lisp_frame_poly(ao_lisp_frame_current)); DBG("\n"); break; + case AO_LISP_STACK: + DBGI(".. stack "); DBG_POLY(ao_lisp_v); DBG("\n"); + ao_lisp_v = ao_lisp_stack_eval(); + DBGI(".. value "); DBG_POLY(ao_lisp_v); DBG("\n"); + DBGI(".. frame "); DBG_POLY(ao_lisp_frame_poly(ao_lisp_frame_current)); DBG("\n"); + break; } - ao_lisp_stack->values = AO_LISP_NIL; - ao_lisp_stack->values_tail = AO_LISP_NIL; return 1; } @@ -599,6 +484,16 @@ static int (*const evals[])(void) = { [eval_macro] = ao_lisp_eval_macro, }; +const char *ao_lisp_state_names[] = { + "sexpr", + "val", + "formal", + "exec", + "cond", + "cond_test", + "progn", +}; + /* * Called at restore time to reset all execution state */ diff --git a/src/lisp/ao_lisp_frame.c b/src/lisp/ao_lisp_frame.c index 9d17f6fa..17fa141a 100644 --- a/src/lisp/ao_lisp_frame.c +++ b/src/lisp/ao_lisp_frame.c @@ -24,7 +24,7 @@ static int frame_size(void *addr) { struct ao_lisp_frame *frame = addr; - return frame_num_size(ao_lisp_frame_num(frame)); + return frame_num_size(frame->num); } static void @@ -37,7 +37,7 @@ frame_mark(void *addr) MDBG_MOVE("frame mark %d\n", MDBG_OFFSET(frame)); if (!AO_LISP_IS_POOL(frame)) break; - for (f = 0; f < ao_lisp_frame_num(frame); f++) { + for (f = 0; f < frame->num; f++) { struct ao_lisp_val *v = &frame->vals[f]; ao_lisp_poly_mark(v->val, 0); @@ -68,7 +68,7 @@ frame_move(void *addr) MDBG_MOVE("frame move %d\n", MDBG_OFFSET(frame)); if (!AO_LISP_IS_POOL(frame)) break; - for (f = 0; f < ao_lisp_frame_num(frame); f++) { + for (f = 0; f < frame->num; f++) { struct ao_lisp_val *v = &frame->vals[f]; ao_lisp_poly_move(&v->atom, 0); @@ -109,15 +109,21 @@ ao_lisp_frame_print(ao_poly p) printf ("{"); if (frame) { - for (f = 0; f < ao_lisp_frame_num(frame); f++) { - if (f != 0) - printf(", "); - ao_lisp_poly_print(frame->vals[f].atom); - printf(" = "); - ao_lisp_poly_print(frame->vals[f].val); + if (frame->type & AO_LISP_FRAME_PRINT) + printf("recurse..."); + else { + frame->type |= AO_LISP_FRAME_PRINT; + for (f = 0; f < frame->num; f++) { + if (f != 0) + printf(", "); + ao_lisp_poly_print(frame->vals[f].atom); + printf(" = "); + ao_lisp_poly_print(frame->vals[f].val); + } + if (frame->prev) + ao_lisp_poly_print(frame->prev); + frame->type &= ~AO_LISP_FRAME_PRINT; } - if (frame->prev) - ao_lisp_poly_print(frame->prev); } printf("}"); } @@ -126,7 +132,7 @@ ao_poly * ao_lisp_frame_ref(struct ao_lisp_frame *frame, ao_poly atom) { int f; - for (f = 0; f < ao_lisp_frame_num(frame); f++) + for (f = 0; f < frame->num; f++) if (frame->vals[f].atom == atom) return &frame->vals[f].val; return NULL; @@ -175,7 +181,7 @@ ao_lisp_frame_new(int num) return NULL; } frame->type = AO_LISP_FRAME; - frame->_num = num; + frame->num = num; frame->prev = AO_LISP_NIL; memset(frame->vals, '\0', num * sizeof (struct ao_lisp_val)); return frame; @@ -186,7 +192,7 @@ ao_lisp_frame_mark(struct ao_lisp_frame *frame) { if (!frame) return AO_LISP_NIL; - frame->_num |= AO_LISP_FRAME_MARK; + frame->type |= AO_LISP_FRAME_MARK; return ao_lisp_frame_poly(frame); } @@ -194,7 +200,7 @@ void ao_lisp_frame_free(struct ao_lisp_frame *frame) { if (!ao_lisp_frame_marked(frame)) { - int num = ao_lisp_frame_num(frame); + int num = frame->num; if (num < AO_LISP_FRAME_FREE) { frame->prev = ao_lisp_frame_poly(ao_lisp_frame_free_list[num]); ao_lisp_frame_free_list[num] = frame; @@ -209,7 +215,7 @@ ao_lisp_frame_realloc(struct ao_lisp_frame **frame_ref, int new_num) struct ao_lisp_frame *new; int copy; - if (new_num == ao_lisp_frame_num(frame)) + if (new_num == frame->num) return frame; new = ao_lisp_frame_new(new_num); if (!new) @@ -220,8 +226,8 @@ ao_lisp_frame_realloc(struct ao_lisp_frame **frame_ref, int new_num) */ frame = *frame_ref; copy = new_num; - if (copy > ao_lisp_frame_num(frame)) - copy = ao_lisp_frame_num(frame); + if (copy > frame->num) + copy = frame->num; memcpy(new->vals, frame->vals, copy * sizeof (struct ao_lisp_val)); new->prev = frame->prev; ao_lisp_frame_free(frame); @@ -239,7 +245,7 @@ ao_lisp_frame_add(struct ao_lisp_frame **frame_ref, ao_poly atom, ao_poly val) ao_lisp_poly_stash(0, atom); ao_lisp_poly_stash(1, val); if (frame) { - f = ao_lisp_frame_num(frame); + f = frame->num; frame = ao_lisp_frame_realloc(frame_ref, f + 1); } else { f = 0; diff --git a/src/lisp/ao_lisp_lambda.c b/src/lisp/ao_lisp_lambda.c index e2053a6f..656936cb 100644 --- a/src/lisp/ao_lisp_lambda.c +++ b/src/lisp/ao_lisp_lambda.c @@ -175,7 +175,8 @@ ao_lisp_lambda_eval(void) args = ao_lisp_poly_cons(args->cdr); vals = ao_lisp_poly_cons(vals->cdr); } - ao_lisp_cons_free(cons); + if (!ao_lisp_stack_marked(ao_lisp_stack)) + ao_lisp_cons_free(cons); cons = NULL; break; case AO_LISP_FUNC_LEXPR: diff --git a/src/lisp/ao_lisp_make_const.c b/src/lisp/ao_lisp_make_const.c index 495e48cd..de9c5725 100644 --- a/src/lisp/ao_lisp_make_const.c +++ b/src/lisp/ao_lisp_make_const.c @@ -71,6 +71,7 @@ struct builtin_func funcs[] = { { .name = "led", .args = AO_LISP_FUNC_F_LEXPR, .func = builtin_led }, { .name = "save", .args = AO_LISP_FUNC_F_LAMBDA, .func = builtin_save }, { .name = "restore", .args = AO_LISP_FUNC_F_LAMBDA, .func = builtin_restore }, + { .name = "call/cc", .args = AO_LISP_FUNC_F_LAMBDA, .func = builtin_call_cc }, }; #define N_FUNC (sizeof funcs / sizeof funcs[0]) @@ -358,7 +359,7 @@ main(int argc, char **argv) /* Reduce to referenced values */ ao_lisp_collect(AO_LISP_COLLECT_FULL); - for (f = 0; f < ao_lisp_frame_num(ao_lisp_frame_global); f++) { + for (f = 0; f < ao_lisp_frame_global->num; f++) { val = ao_has_macro(ao_lisp_frame_global->vals[f].val); if (val != AO_LISP_NIL) { printf("error: function %s contains unresolved macro: ", diff --git a/src/lisp/ao_lisp_mem.c b/src/lisp/ao_lisp_mem.c index 12a5ba55..0dfad1d7 100644 --- a/src/lisp/ao_lisp_mem.c +++ b/src/lisp/ao_lisp_mem.c @@ -144,6 +144,7 @@ struct ao_lisp_root { static struct ao_lisp_cons *save_cons[2]; static char *save_string[2]; +static struct ao_lisp_stack *save_stack[3]; static ao_poly save_poly[2]; static const struct ao_lisp_root ao_lisp_root[] = { @@ -155,6 +156,18 @@ static const struct ao_lisp_root ao_lisp_root[] = { .type = &ao_lisp_cons_type, .addr = (void **) &save_cons[1], }, + { + .type = &ao_lisp_stack_type, + .addr = (void **) &save_stack[0] + }, + { + .type = &ao_lisp_stack_type, + .addr = (void **) &save_stack[1] + }, + { + .type = &ao_lisp_stack_type, + .addr = (void **) &save_stack[2] + }, { .type = &ao_lisp_string_type, .addr = (void **) &save_string[0] @@ -434,6 +447,7 @@ static const struct ao_lisp_type const *ao_lisp_types[AO_LISP_NUM_TYPE] = { [AO_LISP_BUILTIN] = &ao_lisp_builtin_type, [AO_LISP_FRAME] = &ao_lisp_frame_type, [AO_LISP_LAMBDA] = &ao_lisp_lambda_type, + [AO_LISP_STACK] = &ao_lisp_stack_type, }; static int @@ -818,6 +832,20 @@ ao_lisp_cons_fetch(int id) return cons; } +void +ao_lisp_stack_stash(int id, struct ao_lisp_stack *stack) +{ + save_stack[id] = stack; +} + +struct ao_lisp_stack * +ao_lisp_stack_fetch(int id) +{ + struct ao_lisp_stack *stack = save_stack[id]; + save_stack[id] = NULL; + return stack; +} + void ao_lisp_string_stash(int id, char *string) { diff --git a/src/lisp/ao_lisp_poly.c b/src/lisp/ao_lisp_poly.c index 236176e7..800ee06d 100644 --- a/src/lisp/ao_lisp_poly.c +++ b/src/lisp/ao_lisp_poly.c @@ -54,6 +54,10 @@ static const struct ao_lisp_funcs ao_lisp_funcs[AO_LISP_NUM_TYPE] = { .print = ao_lisp_lambda_print, .patom = ao_lisp_lambda_print, }, + [AO_LISP_STACK] = { + .print = ao_lisp_stack_print, + .patom = ao_lisp_stack_print, + }, }; static const struct ao_lisp_funcs * diff --git a/src/lisp/ao_lisp_stack.c b/src/lisp/ao_lisp_stack.c new file mode 100644 index 00000000..9c773e83 --- /dev/null +++ b/src/lisp/ao_lisp_stack.c @@ -0,0 +1,279 @@ +/* + * Copyright © 2016 Keith Packard + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +#define DBG_EVAL 0 +#include "ao_lisp.h" + +const struct ao_lisp_type ao_lisp_stack_type; + +static int +stack_size(void *addr) +{ + (void) addr; + return sizeof (struct ao_lisp_stack); +} + +static void +stack_mark(void *addr) +{ + struct ao_lisp_stack *stack = addr; + for (;;) { + ao_lisp_poly_mark(stack->sexprs, 0); + ao_lisp_poly_mark(stack->values, 0); + /* no need to mark values_tail */ + ao_lisp_poly_mark(stack->frame, 0); + ao_lisp_poly_mark(stack->list, 0); + stack = ao_lisp_poly_stack(stack->prev); + if (ao_lisp_mark_memory(&ao_lisp_stack_type, stack)) + break; + } +} + +static void +stack_move(void *addr) +{ + struct ao_lisp_stack *stack = addr; + + while (stack) { + struct ao_lisp_stack *prev; + int ret; + (void) ao_lisp_poly_move(&stack->sexprs, 0); + (void) ao_lisp_poly_move(&stack->values, 0); + (void) ao_lisp_poly_move(&stack->values_tail, 0); + (void) ao_lisp_poly_move(&stack->frame, 0); + (void) ao_lisp_poly_move(&stack->list, 0); + prev = ao_lisp_poly_stack(stack->prev); + if (!prev) + break; + ret = ao_lisp_move_memory(&ao_lisp_stack_type, (void **) &prev); + if (prev != ao_lisp_poly_stack(stack->prev)) + stack->prev = ao_lisp_stack_poly(prev); + if (ret) + break; + stack = prev; + } +} + +const struct ao_lisp_type ao_lisp_stack_type = { + .size = stack_size, + .mark = stack_mark, + .move = stack_move, + .name = "stack" +}; + +struct ao_lisp_stack *ao_lisp_stack_free_list; + +void +ao_lisp_stack_reset(struct ao_lisp_stack *stack) +{ + stack->state = eval_sexpr; + stack->sexprs = AO_LISP_NIL; + stack->values = AO_LISP_NIL; + stack->values_tail = AO_LISP_NIL; +} + +static struct ao_lisp_stack * +ao_lisp_stack_new(void) +{ + struct ao_lisp_stack *stack; + + if (ao_lisp_stack_free_list) { + stack = ao_lisp_stack_free_list; + ao_lisp_stack_free_list = ao_lisp_poly_stack(stack->prev); + } else { + stack = ao_lisp_alloc(sizeof (struct ao_lisp_stack)); + if (!stack) + return 0; + stack->type = AO_LISP_STACK; + } + ao_lisp_stack_reset(stack); + return stack; +} + +int +ao_lisp_stack_push(void) +{ + struct ao_lisp_stack *stack = ao_lisp_stack_new(); + + if (!stack) + return 0; + + stack->prev = ao_lisp_stack_poly(ao_lisp_stack); + stack->frame = ao_lisp_frame_poly(ao_lisp_frame_current); + stack->list = AO_LISP_NIL; + + ao_lisp_stack = stack; + + DBGI("stack push\n"); + DBG_FRAMES(); + DBG_IN(); + return 1; +} + +void +ao_lisp_stack_pop(void) +{ + ao_poly prev; + struct ao_lisp_frame *prev_frame; + + if (!ao_lisp_stack) + return; + prev = ao_lisp_stack->prev; + if (!ao_lisp_stack_marked(ao_lisp_stack)) { + ao_lisp_stack->prev = ao_lisp_stack_poly(ao_lisp_stack_free_list); + ao_lisp_stack_free_list = ao_lisp_stack; + } + + ao_lisp_stack = ao_lisp_poly_stack(prev); + prev_frame = ao_lisp_frame_current; + if (ao_lisp_stack) + ao_lisp_frame_current = ao_lisp_poly_frame(ao_lisp_stack->frame); + else + ao_lisp_frame_current = NULL; + if (ao_lisp_frame_current != prev_frame) + ao_lisp_frame_free(prev_frame); + DBG_OUT(); + DBGI("stack pop\n"); + DBG_FRAMES(); +} + +void +ao_lisp_stack_clear(void) +{ + ao_lisp_stack = NULL; + ao_lisp_frame_current = NULL; + ao_lisp_v = AO_LISP_NIL; +} + +void +ao_lisp_stack_print(ao_poly poly) +{ + struct ao_lisp_stack *s = ao_lisp_poly_stack(poly); + + if (s->type & AO_LISP_STACK_PRINT) { + printf("[recurse...]"); + return; + } + while (s) { + s->type |= AO_LISP_STACK_PRINT; + printf("\t[\n"); + printf("\t\texpr: "); ao_lisp_poly_print(s->list); printf("\n"); + printf("\t\tstate: %s\n", ao_lisp_state_names[s->state]); + ao_lisp_error_poly ("values: ", s->values, s->values_tail); + ao_lisp_error_poly ("sexprs: ", s->sexprs, AO_LISP_NIL); + ao_lisp_error_frame(2, "frame: ", ao_lisp_poly_frame(s->frame)); + printf("\t]\n"); + s->type &= ~AO_LISP_STACK_PRINT; + s = ao_lisp_poly_stack(s->prev); + } +} + +/* + * Copy a stack, being careful to keep everybody referenced + */ +static struct ao_lisp_stack * +ao_lisp_stack_copy(struct ao_lisp_stack *old) +{ + struct ao_lisp_stack *new = NULL; + struct ao_lisp_stack *n, *prev = NULL; + + while (old) { + ao_lisp_stack_stash(0, old); + ao_lisp_stack_stash(1, new); + ao_lisp_stack_stash(2, prev); + n = ao_lisp_stack_new(); + prev = ao_lisp_stack_fetch(2); + new = ao_lisp_stack_fetch(1); + old = ao_lisp_stack_fetch(0); + if (!n) + return NULL; + + ao_lisp_stack_mark(old); + ao_lisp_frame_mark(ao_lisp_poly_frame(old->frame)); + *n = *old; + + if (prev) + prev->prev = ao_lisp_stack_poly(n); + else + new = n; + prev = n; + + old = ao_lisp_poly_stack(old->prev); + } + return new; +} + +/* + * Evaluate a continuation invocation + */ +ao_poly +ao_lisp_stack_eval(void) +{ + struct ao_lisp_stack *new = ao_lisp_stack_copy(ao_lisp_poly_stack(ao_lisp_v)); + if (!new) + return AO_LISP_NIL; + + struct ao_lisp_cons *cons = ao_lisp_poly_cons(ao_lisp_stack->values); + + if (!cons || !cons->cdr) + return ao_lisp_error(AO_LISP_INVALID, "continuation requires a value"); + + new->state = eval_val; + + ao_lisp_stack = new; + ao_lisp_frame_current = ao_lisp_poly_frame(ao_lisp_stack->frame); + + return ao_lisp_poly_cons(cons->cdr)->car; +} + +/* + * Call with current continuation. This calls a lambda, passing + * it a single argument which is the current continuation + */ +ao_poly +ao_lisp_call_cc(struct ao_lisp_cons *cons) +{ + struct ao_lisp_stack *new; + ao_poly v; + + /* Make sure the single parameter is a lambda */ + if (!ao_lisp_check_argc(_ao_lisp_atom_call2fcc, cons, 1, 1)) + return AO_LISP_NIL; + if (!ao_lisp_check_argt(_ao_lisp_atom_call2fcc, cons, 0, AO_LISP_LAMBDA, 0)) + return AO_LISP_NIL; + + /* go get the lambda */ + ao_lisp_v = ao_lisp_arg(cons, 0); + + /* Note that the whole call chain now has + * a reference to it which may escape + */ + new = ao_lisp_stack_copy(ao_lisp_stack); + if (!new) + return AO_LISP_NIL; + + /* re-fetch cons after the allocation */ + cons = ao_lisp_poly_cons(ao_lisp_poly_cons(ao_lisp_stack->values)->cdr); + + /* Reset the arg list to the current stack, + * and call the lambda + */ + + cons->car = ao_lisp_stack_poly(new); + cons->cdr = AO_LISP_NIL; + v = ao_lisp_lambda_eval(); + ao_lisp_stack->sexprs = v; + ao_lisp_stack->state = eval_progn; + return AO_LISP_NIL; +} -- 2.30.2