10 #include "script/parser.h"
11 #include "system/lt.h"
12 #include "system/lt/lt_adapters.h"
14 #define MAX_BUFFER_LENGTH (5 * 1000 * 1000)
16 static struct ParseResult parse_expr(Gc *gc, struct Token current_token);
18 static struct ParseResult parse_cdr(Gc *gc, struct Token current_token)
20 if (*current_token.begin != '.') {
21 return parse_failure("Expected .", current_token.begin);
24 struct ParseResult cdr = read_expr_from_string(gc, current_token.end);
29 current_token = next_token(cdr.end);
31 if (*current_token.begin != ')') {
32 return parse_failure("Expected )", current_token.begin);
35 return parse_success(cdr.expr, current_token.end);
38 static struct ParseResult parse_list_end(Gc *gc, struct Token current_token)
40 if (*current_token.begin != ')') {
41 return parse_failure("Expected )", current_token.begin);
44 return parse_success(atom_as_expr(create_symbol_atom(gc, "nil", NULL)),
48 static struct ParseResult parse_list(Gc *gc, struct Token current_token)
50 if (*current_token.begin != '(') {
51 return parse_failure("Expected (", current_token.begin);
54 current_token = next_token(current_token.end);
56 if (*current_token.begin == ')') {
57 return parse_list_end(gc, current_token);
60 struct ParseResult car = parse_expr(gc, current_token);
65 struct Cons *list = create_cons(gc, car.expr, void_expr());
66 struct Cons *cons = list;
67 current_token = next_token(car.end);
69 while (*current_token.begin != '.' &&
70 *current_token.begin != ')' &&
71 *current_token.begin != 0) {
72 car = parse_expr(gc, current_token);
77 cons->cdr = cons_as_expr(create_cons(gc, car.expr, void_expr()));
78 cons = cons->cdr.cons;
80 current_token = next_token(car.end);
83 struct ParseResult cdr = *current_token.begin == '.'
84 ? parse_cdr(gc, current_token)
85 : parse_list_end(gc, current_token);
93 return parse_success(cons_as_expr(list), cdr.end);
96 static struct ParseResult parse_string(Gc *gc, struct Token current_token)
98 if (*current_token.begin != '"') {
99 return parse_failure("Expected \"", current_token.begin);
102 if (*(current_token.end - 1) != '"') {
103 return parse_failure("Unclosed string", current_token.begin);
106 if (current_token.begin + 1 == current_token.end) {
107 return parse_success(atom_as_expr(create_string_atom(gc, "", NULL)),
111 return parse_success(
113 create_string_atom(gc, current_token.begin + 1, current_token.end - 1)),
117 static struct ParseResult parse_number(Gc *gc, struct Token current_token)
120 const long int x = strtoimax(current_token.begin, &endptr, 10);
122 if (current_token.begin == endptr || current_token.end != endptr) {
123 return parse_failure("Expected number", current_token.begin);
126 return parse_success(
127 atom_as_expr(create_number_atom(gc, x)),
131 static struct ParseResult parse_symbol(Gc *gc, struct Token current_token)
133 if (*current_token.begin == 0) {
134 return parse_failure("EOF", current_token.begin);
137 return parse_success(
138 atom_as_expr(create_symbol_atom(gc, current_token.begin, current_token.end)),
142 static struct ParseResult parse_expr(Gc *gc, struct Token current_token)
144 if (*current_token.begin == 0) {
145 return parse_failure("EOF", current_token.begin);
148 switch (*current_token.begin) {
149 case '(': return parse_list(gc, current_token);
150 /* TODO(#292): parser does not support escaped string characters */
151 case '"': return parse_string(gc, current_token);
155 if (isdigit(*current_token.begin)) {
156 return parse_number(gc, current_token);
159 return parse_symbol(gc, current_token);
162 struct ParseResult read_expr_from_string(Gc *gc, const char *str)
165 return parse_expr(gc, next_token(str));
168 struct ParseResult read_expr_from_file(Gc *gc, const char *filename)
172 Lt *lt = create_lt();
174 return parse_failure("Could not create Lt object", NULL);
177 FILE *stream = PUSH_LT(lt, fopen(filename, "rb"), fclose_lt);
179 /* TODO(#307): ParseResult should not be used for reporting IO failures */
180 RETURN_LT(lt, parse_failure(strerror(errno), NULL));
183 if (fseek(stream, 0, SEEK_END) != 0) {
184 RETURN_LT(lt, parse_failure("Could not find the end of the file", NULL));
187 const long int buffer_length = ftell(stream);
189 if (buffer_length < 0) {
190 RETURN_LT(lt, parse_failure("Couldn't get the size of file", NULL));
193 if (buffer_length == 0) {
194 RETURN_LT(lt, parse_failure("File is empty", NULL));
197 if (buffer_length >= MAX_BUFFER_LENGTH) {
198 RETURN_LT(lt, parse_failure("File is too big", NULL));
201 if (fseek(stream, 0, SEEK_SET) != 0) {
202 RETURN_LT(lt, parse_failure("Could not find the beginning of the file", NULL));
205 char * const buffer = PUSH_LT(lt, malloc((size_t) buffer_length + 1), free);
206 if (buffer == NULL) {
207 RETURN_LT(lt, parse_failure(strerror(errno), NULL));
210 if (fread(buffer, 1, (size_t) buffer_length, stream) != (size_t) buffer_length) {
211 RETURN_LT(lt, parse_failure("Could not read the file", NULL));
214 struct ParseResult result = read_expr_from_string(gc, buffer);
216 RETURN_LT(lt, result);
219 struct ParseResult parse_success(struct Expr expr,
222 struct ParseResult result = {
231 struct ParseResult parse_failure(const char *error_message,
234 struct ParseResult result = {
236 .error_message = error_message,
243 void print_parse_error(FILE *stream,
245 struct ParseResult result)
247 /* TODO(#294): print_parse_error doesn't support multiple lines */
248 if (!result.is_error) {
253 fprintf(stream, "%s\n", str);
254 for (size_t i = 0; i < (size_t) (result.end - str); ++i) {
255 fprintf(stream, " ");
257 fprintf(stream, "^\n");
260 fprintf(stream, "%s\n", result.error_message);