undar-lang/parser.c

178 lines
3.1 KiB
C

#include "parser.h"
Parser parser;
bool
advance()
{
parser.previous = parser.current;
for(;;) {
parser.current = next_token();
if(parser.current.type != TOKEN_ERROR) return true;
return false;
}
}
bool
push(TokenStack *ts, Token t)
{
if(ts->count >= ts->capacity) return false;
ts->stack[ts->count++] = t;
return true;
}
Token
pop(TokenStack *ts)
{
if(ts->count == 0) return (Token){TOKEN_ERROR, nil, -1, -1};
return ts->stack[--ts->count];
}
Token
top(TokenStack *ts)
{
if(ts->count == 0) return (Token){TOKEN_ERROR, nil, -1, -1};
return ts->stack[ts->count - 1];
}
bool
enqueue(TokenQueue *tq, Token t)
{
if(tq->count >= tq->capacity) return false;
tq->queue[tq->end] = t;
tq->end = (tq->end + 1) % tq->capacity; // Wrap around
tq->count++;
return true;
}
Token
dequeue(TokenQueue *tq)
{
if(tq->count == 0) return (Token){TOKEN_ERROR, NULL, -1, -1};
Token t = tq->queue[tq->start];
tq->start = (tq->start + 1) % tq->capacity; // Wrap around
tq->count--;
return t;
}
Token
peek_queue(TokenQueue *tq)
{
if(tq->count == 0) return (Token){TOKEN_ERROR, NULL, -1, -1};
return tq->queue[tq->start];
}
u32
idx_from_arena(Arena *arena, void *p)
{
return (u32)((u8 *)p - arena->tape);
}
void *
ptr_from_arena(Arena *arena, u32 i)
{
return &arena->tape[i];
}
ArenaList *
al_create(Arena *arena, u32 size)
{
ArenaList *meta = aalloc(arena, sizeof(ArenaList));
if(!meta) return nil;
meta->size = size + sizeof(u32);
meta->arena = arena;
meta->head = 0;
meta->tail = 0;
return meta;
}
void *
al_append(ArenaList *list, void **out_payload)
{
void *node = aalloc(list->arena, list->size);
if(!node) return nil;
u32 idx = idx_from_arena(list->arena, node);
void *payload = node; /* Payload starts at offset 0 */
void *cdr_ptr = (u8 *)node + (list->size - sizeof(u32));
*(u32 *)cdr_ptr = 0;
if(list->tail != 0) {
void *prev_node = ptr_from_arena(list->arena, list->tail);
void *prev_cdr = (u8 *)prev_node + (list->size - sizeof(u32));
*(u32 *)prev_cdr = idx;
} else {
list->head = idx;
}
list->tail = idx;
if(out_payload) *out_payload = payload;
return payload;
}
void *
al_head(ArenaList *list)
{
if(list->head == 0) return nil;
return ptr_from_arena(list->arena, list->head);
}
void *
al_tail(ArenaList *list)
{
if(list->tail == 0) return nil;
return ptr_from_arena(list->arena, list->tail);
}
SymbolLink *
symbol_table_find(ArenaList *table, const char *name)
{
void *current = al_head(table);
Arena *arena = table->arena;
while(current != nil) {
SymbolLink *link = (SymbolLink *)current;
if(seq(link->s.name.start, name)) return link;
u32 next_idx = link->cdr;
current = (next_idx == 0) ? nil : ptr_from_arena(arena, next_idx);
}
return nil;
}
/****************************************************
* Parser
***************************************************/
bool
expression()
{
Token operator_stack[256];
TokenStack operators = {0};
operators.stack = operator_stack;
operators.capacity = 256;
Token output_queue[256];
TokenQueue output = {0};
output.queue = output_queue;
output.capacity = 256;
return true;
}
bool
compile(char *source)
{
return true;
}