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#include "parser.h"
#include "darray.h"
Node *
alloc_node(NodeType type) {
// TODO: Use a bump allocator?
// TODO: Free memory!
Node *node = malloc(sizeof(Node));
node->type = type;
return node;
}
Token
next_token(Parser *parser) {
return parser->tokens[parser->current++];
}
Token
peek_token(Parser *parser) {
return parser->tokens[parser->current];
}
bool
has_next(Parser *parser) {
return parser->current < array_size(parser->tokens);
}
Node *
parse_number(Parser *parser) {
Token tok = next_token(parser);
bool negative = false;
int base = 10;
char c = sv_next(&tok.value);
if (c == '-') {
negative = true;
c = sv_next(&tok.value);
}
if (c == '+') {
c = sv_next(&tok.value);
}
if (c == '0') {
c = sv_next(&tok.value);
if (c == 'x') {
base = 16;
c = sv_next(&tok.value);
} else if (c == 'b') {
base = 2;
c = sv_next(&tok.value);
} else if (!(c >= '0' && c <= '9')){
push_error(ERR_TYPE_PARSER, ERR_MALFORMED_NUMBER, tok.line, tok.col);
return NULL;
}
}
// Integral part.
u64 integral = 0;
while (c != '\0') {
ssize_t current = 0;
if (c >= 'a' && c <= 'z' && base == 16) {
current = (c - 'a') + 10;
} else if (c >= 'A' && c <= 'Z' && base == 16) {
current = (c - 'A') + 10;
} else if (c >= '0' && c <= '9') {
current = (c - '0');
} else if (c == '.') {
c = sv_next(&tok.value);
break;
} else {
push_error(ERR_TYPE_PARSER, ERR_MALFORMED_NUMBER, tok.line, tok.col);
return NULL;
}
integral = integral * base + current;
c = sv_next(&tok.value);
}
// Fractional part.
u64 fractional = 0;
while (c != '\0') {
ssize_t current = 0;
if (c >= 'a' && c <= 'z' && base == 16) {
current = (c - 'a') + 10;
} else if (c >= 'A' && c <= 'Z' && base == 16) {
current = (c - 'A') + 10;
} else if (c >= '0' && c <= '9') {
current = (c - '0');
} else {
push_error(ERR_TYPE_PARSER, ERR_MALFORMED_NUMBER, tok.line, tok.col);
return NULL;
}
fractional = fractional * base + current;
c = sv_next(&tok.value);
}
Node * node = alloc_node(NODE_NUMBER);
node->number.negative = negative;
node->number.integral = integral;
node->number.fractional = fractional;
return node;
}
Node *
parse_string(Parser *parser) {
Token tok = next_token(parser);
Node *node = alloc_node(NODE_STRING);
node->string = tok.value;
return node;
}
Node *
parse_builtin(Parser *parser) {
Token op = next_token(parser);
Node *node = alloc_node(NODE_BUILTIN);
node->builtin.type = op.type;
array_init(node->builtin.args, 0);
while (has_next(parser)) {
Token next = peek_token(parser);
if (next.type == TOKEN_RPAREN) {
next_token(parser);
return node;
}
Node *arg = parse_next(parser);
if (arg == NULL) {
break;
}
array_push(node->builtin.args, arg);
}
push_error(ERR_TYPE_PARSER, ERR_UNMATCHED_PAREN, op.line, op.col);
return NULL;
}
Node *
parse_paren(Parser *parser) {
next_token(parser); // Skip paren.
Token tok = peek_token(parser);
// TODO: is keyword?
switch (tok.type) {
case TOKEN_ADD:
case TOKEN_SUB:
case TOKEN_MUL:
case TOKEN_DIV:
case TOKEN_MOD: {
return parse_builtin(parser);
} break;
default: break;
}
// print_token(tok);
// TODO: is in symbol table and its value is a function?
return NULL; // TODO: Not implemented
}
Node *
parse_next(Parser *parser) {
Token tok = peek_token(parser);
switch (tok.type) {
case TOKEN_NUMBER: {
return parse_number(parser);
} break;
case TOKEN_STRING: {
return parse_string(parser);
} break;
case TOKEN_LPAREN: {
return parse_paren(parser);
} break;
case TOKEN_EOF: {
return NULL;
} break;
default: {
push_error(ERR_TYPE_PARSER, ERR_UNKNOWN_TOK_TYPE, tok.line, tok.col);
return NULL;
} break;
}
}
void
print_node(Node *node) {
switch (node->type) {
case NODE_NUMBER: {
if (node->number.negative) {
printf("-");
}
if (node->number.fractional != 0) {
printf("%zu.%zu", node->number.integral, node->number.fractional);
} else {
printf("%zu", node->number.integral);
}
} break;
case NODE_STRING: {
sv_write(&node->string);
} break;
case NODE_BUILTIN: {
printf("(");
printf("{#%s}", token_str[node->builtin.type]);
size_t n_args = array_size(node->builtin.args);
if (n_args != 0) {
printf(" ");
}
for (size_t i = 0; i < n_args; ++i) {
print_node(node->builtin.args[i]);
if (i < n_args - 1) {
printf(" ");
}
}
printf(")");
} break;
default: { printf("{#unk}"); } break;
}
}
void
parse(Token *tokens) {
Parser parser = {
.tokens = tokens,
.current = 0,
};
// DEBUG: TOKENS
printf("-- tokens --\n");
for (size_t i = 0; i < array_size(tokens); i++) {
print_token(tokens[i]);
}
printf("------------\n");
while (has_next(&parser)) {
Node *node = parse_next(&parser);
if (node == NULL) {
return;
}
print_node(node);
printf("\n");
}
}
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