feat: add base parser

Signed-off-by: kjuulh <contact@kjuulh.io>

feat: with basic assignment

Signed-off-by: kjuulh <contact@kjuulh.io>

feat: remove target

Signed-off-by: kjuulh <contact@kjuulh.io>

src/scanner.c

@@ -0,0 +1,191 @@
+#include <tree_sitter/parser.h>
+#include <wctype.h>
+
+enum TokenType {
+  STRING_CONTENT,
+  RAW_STRING_LITERAL,
+  FLOAT_LITERAL,
+  BLOCK_COMMENT,
+};
+
+void *tree_sitter_rhai_external_scanner_create() { return NULL; }
+void tree_sitter_rhai_external_scanner_destroy(void *p) {}
+void tree_sitter_rhai_external_scanner_reset(void *p) {}
+unsigned tree_sitter_rhai_external_scanner_serialize(void *p, char *buffer) {
+  return 0;
+}
+void tree_sitter_rhai_external_scanner_deserialize(void *p, const char *b,
+                                                   unsigned n) {}
+
+static void advance(TSLexer *lexer) { lexer->advance(lexer, false); }
+
+static bool is_num_char(int32_t c) { return c == '_' || iswdigit(c); }
+
+bool tree_sitter_rhai_external_scanner_scan(void *payload, TSLexer *lexer,
+                                            const bool *valid_symbols) {
+  if (valid_symbols[STRING_CONTENT] && !valid_symbols[FLOAT_LITERAL]) {
+    bool has_content = false;
+    for (;;) {
+      if (lexer->lookahead == '\"' || lexer->lookahead == '\\') {
+        break;
+      } else if (lexer->lookahead == 0) {
+        return false;
+      }
+      has_content = true;
+      advance(lexer);
+    }
+    lexer->result_symbol = STRING_CONTENT;
+    return has_content;
+  }
+
+  while (iswspace(lexer->lookahead))
+    lexer->advance(lexer, true);
+
+  if (valid_symbols[RAW_STRING_LITERAL] &&
+      (lexer->lookahead == 'r' || lexer->lookahead == 'b')) {
+    lexer->result_symbol = RAW_STRING_LITERAL;
+    if (lexer->lookahead == 'b')
+      advance(lexer);
+    if (lexer->lookahead != 'r')
+      return false;
+    advance(lexer);
+
+    unsigned opening_hash_count = 0;
+    while (lexer->lookahead == '#') {
+      advance(lexer);
+      opening_hash_count++;
+    }
+
+    if (lexer->lookahead != '"')
+      return false;
+    advance(lexer);
+
+    for (;;) {
+      if (lexer->lookahead == 0) {
+        return false;
+      } else if (lexer->lookahead == '"') {
+        advance(lexer);
+        unsigned hash_count = 0;
+        while (lexer->lookahead == '#' && hash_count < opening_hash_count) {
+          advance(lexer);
+          hash_count++;
+        }
+        if (hash_count == opening_hash_count) {
+          return true;
+        }
+      } else {
+        advance(lexer);
+      }
+    }
+  }
+
+  if (valid_symbols[FLOAT_LITERAL] && iswdigit(lexer->lookahead)) {
+    lexer->result_symbol = FLOAT_LITERAL;
+
+    advance(lexer);
+    while (is_num_char(lexer->lookahead)) {
+      advance(lexer);
+    }
+
+    bool has_fraction = false, has_exponent = false;
+
+    if (lexer->lookahead == '.') {
+      has_fraction = true;
+      advance(lexer);
+      if (iswalpha(lexer->lookahead)) {
+        // The dot is followed by a letter: 1.max(2) => not a float but an
+        // integer
+        return false;
+      }
+
+      if (lexer->lookahead == '.') {
+        return false;
+      }
+      while (is_num_char(lexer->lookahead)) {
+        advance(lexer);
+      }
+    }
+
+    lexer->mark_end(lexer);
+
+    if (lexer->lookahead == 'e' || lexer->lookahead == 'E') {
+      has_exponent = true;
+      advance(lexer);
+      if (lexer->lookahead == '+' || lexer->lookahead == '-') {
+        advance(lexer);
+      }
+      if (!is_num_char(lexer->lookahead)) {
+        return true;
+      }
+      advance(lexer);
+      while (is_num_char(lexer->lookahead)) {
+        advance(lexer);
+      }
+
+      lexer->mark_end(lexer);
+    }
+
+    if (!has_exponent && !has_fraction)
+      return false;
+
+    if (lexer->lookahead != 'u' && lexer->lookahead != 'i' &&
+        lexer->lookahead != 'f') {
+      return true;
+    }
+    advance(lexer);
+    if (!iswdigit(lexer->lookahead)) {
+      return true;
+    }
+
+    while (iswdigit(lexer->lookahead)) {
+      advance(lexer);
+    }
+
+    lexer->mark_end(lexer);
+    return true;
+  }
+
+  if (lexer->lookahead == '/') {
+    advance(lexer);
+    if (lexer->lookahead != '*')
+      return false;
+    advance(lexer);
+
+    bool after_star = false;
+    unsigned nesting_depth = 1;
+    for (;;) {
+      switch (lexer->lookahead) {
+      case '\0':
+        return false;
+      case '*':
+        advance(lexer);
+        after_star = true;
+        break;
+      case '/':
+        if (after_star) {
+          advance(lexer);
+          after_star = false;
+          nesting_depth--;
+          if (nesting_depth == 0) {
+            lexer->result_symbol = BLOCK_COMMENT;
+            return true;
+          }
+        } else {
+          advance(lexer);
+          after_star = false;
+          if (lexer->lookahead == '*') {
+            nesting_depth++;
+            advance(lexer);
+          }
+        }
+        break;
+      default:
+        advance(lexer);
+        after_star = false;
+        break;
+      }
+    }
+  }
+
+  return false;
+}