100 lines
2.4 KiB
C
100 lines
2.4 KiB
C
#include <stdint.h>
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#include <string.h>
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#include <tree_sitter/parser.h>
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enum TokenType {
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COMMENT,
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};
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static int32_t advance(TSLexer *lexer) {
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int32_t last = lexer->lookahead;
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lexer->advance(lexer, false);
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return last;
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}
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static bool expect(TSLexer *lexer, int32_t expected) {
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if (lexer->eof(lexer) || lexer->lookahead != expected) {
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return false;
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}
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advance(lexer);
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return true;
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}
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static void skip_whitespace(TSLexer *lexer) {
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while (!lexer->eof(lexer)) {
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switch (lexer->lookahead) {
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case ' ':
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case '\t':
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case '\n':
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case '\r':
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lexer->advance(lexer, true);
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break;
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default:
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return;
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}
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}
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}
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// Comments start with "/*", end with "*/", and can be nested like OCaml
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static bool scan_comment(TSLexer *lexer) {
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// '/' already consumed outside of the function
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if (!expect(lexer, '*')) {
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return false; // Division etc...
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}
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unsigned long level = 1;
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while (level > 0 && !lexer->eof(lexer)) {
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switch (advance(lexer)) {
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case '/':
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if (expect(lexer, '*')) {
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++level;
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}
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break;
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case '*':
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if (expect(lexer, '/')) {
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--level;
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}
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break;
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}
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}
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return level == 0;
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}
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void *tree_sitter_tiger_external_scanner_create() {
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return NULL;
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}
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void tree_sitter_tiger_external_scanner_destroy(void *payload) {}
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unsigned tree_sitter_tiger_external_scanner_serialize(void *payload,
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char *buffer) {
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return 0;
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}
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void tree_sitter_tiger_external_scanner_deserialize(void *payload,
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char const *buffer,
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unsigned length) {}
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bool tree_sitter_tiger_external_scanner_scan(void *payload,
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TSLexer *lexer,
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bool const *valid_symbols) {
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// Only try to scan when appropriate
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if (!valid_symbols[COMMENT]) {
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return false;
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}
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// Apparently it is expected of us to skip all whitespace by ourselves...
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skip_whitespace(lexer);
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// Comments start with "/*", scan_comment expects '/' to have been consumed
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if (expect(lexer, '/')) {
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lexer->result_symbol = COMMENT;
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return scan_comment(lexer);
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}
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return false;
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}
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