9 #include "script/parser.h"
10 #include "system/lt.h"
11 #include "system/lt/lt_adapters.h"
13 #define MAX_BUFFER_LENGTH (5 * 1000 * 1000)
15 static struct ParseResult parse_expr(Gc *gc, struct Token current_token);
17 static struct ParseResult parse_cdr(Gc *gc, struct Token current_token)
19 if (*current_token.begin != '.') {
20 return parse_failure("Expected .", current_token.begin);
23 struct ParseResult cdr = read_expr_from_string(gc, current_token.end);
28 current_token = next_token(cdr.end);
30 if (*current_token.begin != ')') {
31 return parse_failure("Expected )", current_token.begin);
34 return parse_success(cdr.expr, current_token.end);
37 static struct ParseResult parse_list_end(Gc *gc, struct Token current_token)
39 if (*current_token.begin != ')') {
40 return parse_failure("Expected )", current_token.begin);
43 return parse_success(atom_as_expr(create_symbol_atom(gc, "nil", NULL)),
47 static struct ParseResult parse_list(Gc *gc, struct Token current_token)
49 if (*current_token.begin != '(') {
50 return parse_failure("Expected (", current_token.begin);
53 current_token = next_token(current_token.end);
55 if (*current_token.begin == ')') {
56 return parse_list_end(gc, current_token);
59 struct ParseResult car = parse_expr(gc, current_token);
64 struct Cons *list = create_cons(gc, car.expr, void_expr());
65 struct Cons *cons = list;
66 current_token = next_token(car.end);
68 while (*current_token.begin != '.' &&
69 *current_token.begin != ')' &&
70 *current_token.begin != 0) {
71 car = parse_expr(gc, current_token);
76 cons->cdr = cons_as_expr(create_cons(gc, car.expr, void_expr()));
77 cons = cons->cdr.cons;
79 current_token = next_token(car.end);
82 struct ParseResult cdr = *current_token.begin == '.'
83 ? parse_cdr(gc, current_token)
84 : parse_list_end(gc, current_token);
92 return parse_success(cons_as_expr(list), cdr.end);
95 static struct ParseResult parse_string(Gc *gc, struct Token current_token)
97 if (*current_token.begin != '"') {
98 return parse_failure("Expected \"", current_token.begin);
101 if (*(current_token.end - 1) != '"') {
102 return parse_failure("Unclosed string", current_token.begin);
105 if (current_token.begin + 1 == current_token.end) {
106 return parse_success(atom_as_expr(create_string_atom(gc, "", NULL)),
110 return parse_success(
112 create_string_atom(gc, current_token.begin + 1, current_token.end - 1)),
116 static struct ParseResult parse_number(Gc *gc, struct Token current_token)
119 const float x = strtof(current_token.begin, &endptr);
121 if (current_token.begin == endptr || current_token.end != endptr) {
122 return parse_failure("Expected number", current_token.begin);
125 return parse_success(
126 atom_as_expr(create_number_atom(gc, x)),
130 static struct ParseResult parse_symbol(Gc *gc, struct Token current_token)
132 if (*current_token.begin == 0) {
133 return parse_failure("EOF", current_token.begin);
136 return parse_success(
137 atom_as_expr(create_symbol_atom(gc, current_token.begin, current_token.end)),
141 static struct ParseResult parse_expr(Gc *gc, struct Token current_token)
143 if (*current_token.begin == 0) {
144 return parse_failure("EOF", current_token.begin);
147 switch (*current_token.begin) {
148 case '(': return parse_list(gc, current_token);
149 /* TODO(#292): parser does not support escaped string characters */
150 case '"': return parse_string(gc, current_token);
154 if (isdigit(*current_token.begin)) {
155 return parse_number(gc, current_token);
158 return parse_symbol(gc, current_token);
161 struct ParseResult read_expr_from_string(Gc *gc, const char *str)
164 return parse_expr(gc, next_token(str));
167 struct ParseResult read_expr_from_file(Gc *gc, const char *filename)
171 Lt *lt = create_lt();
173 return parse_failure("Could not create Lt object", NULL);
176 FILE *stream = PUSH_LT(lt, fopen(filename, "rb"), fclose_lt);
178 /* TODO(#307): ParseResult should not be used for reporting IO failures */
179 RETURN_LT(lt, parse_failure(strerror(errno), NULL));
182 if (fseek(stream, 0, SEEK_END) != 0) {
183 RETURN_LT(lt, parse_failure("Could not find the end of the file", NULL));
186 const long int buffer_length = ftell(stream);
188 if (buffer_length < 0) {
189 RETURN_LT(lt, parse_failure("Couldn't get the size of file", NULL));
192 if (buffer_length == 0) {
193 RETURN_LT(lt, parse_failure("File is empty", NULL));
196 if (buffer_length >= MAX_BUFFER_LENGTH) {
197 RETURN_LT(lt, parse_failure("File is too big", NULL));
200 if (fseek(stream, 0, SEEK_SET) != 0) {
201 RETURN_LT(lt, parse_failure("Could not find the beginning of the file", NULL));
204 char * const buffer = PUSH_LT(lt, malloc((size_t) buffer_length + 1), free);
205 if (buffer == NULL) {
206 RETURN_LT(lt, parse_failure(strerror(errno), NULL));
209 if (fread(buffer, 1, (size_t) buffer_length, stream) != (size_t) buffer_length) {
210 RETURN_LT(lt, parse_failure("Could not read the file", NULL));
213 struct ParseResult result = read_expr_from_string(gc, buffer);
215 RETURN_LT(lt, result);
218 struct ParseResult parse_success(struct Expr expr,
221 struct ParseResult result = {
230 struct ParseResult parse_failure(const char *error_message,
233 struct ParseResult result = {
235 .error_message = error_message,
242 void print_parse_error(FILE *stream,
244 struct ParseResult result)
246 /* TODO(#294): print_parse_error doesn't support multiple lines */
247 if (!result.is_error) {
252 fprintf(stream, "%s\n", str);
253 for (size_t i = 0; i < (size_t) (result.end - str); ++i) {
254 fprintf(stream, " ");
256 fprintf(stream, "^\n");
259 fprintf(stream, "%s\n", result.error_message);