Rename lexer struct, param, and functions (#35)

1. `lexerstate` should be `rbs_lexer_t` instead
2. Params representing `rbs_lexer_t` should be named `lexer` instead of
`state`
3. `rbsparser_next_token` should be called `rbs_lexer_next_token`

After this PR, all structs & functions we want to expose should have
`rbs_` prefix.

Author: st0012

ext/rbs_extension/main.c

@@ -129,7 +129,7 @@ static VALUE parse_type_try(VALUE a) {
   return ruby_ast;
 }
 
-static lexstate *alloc_lexer_from_buffer(rbs_allocator_t *allocator, VALUE string, rb_encoding *encoding, int start_pos, int end_pos) {
+static rbs_lexer_t *alloc_lexer_from_buffer(rbs_allocator_t *allocator, VALUE string, rb_encoding *encoding, int start_pos, int end_pos) {
   if (start_pos < 0 || end_pos < 0) {
     rb_raise(rb_eArgError, "negative position range: %d...%d", start_pos, end_pos);
   }
@@ -286,12 +286,12 @@ static VALUE rbsparser_lex(VALUE self, VALUE buffer, VALUE end_pos) {
 
   rbs_allocator_t allocator;
   rbs_allocator_init(&allocator);
-  lexstate *lexer = alloc_lexer_from_buffer(&allocator, string, encoding, 0, FIX2INT(end_pos));
+  rbs_lexer_t *lexer = alloc_lexer_from_buffer(&allocator, string, encoding, 0, FIX2INT(end_pos));
 
   VALUE results = rb_ary_new();
   rbs_token_t token = NullToken;
   while (token.type != pEOF) {
-    token = rbsparser_next_token(lexer);
+    token = rbs_lexer_next_token(lexer);
     VALUE type = ID2SYM(rb_intern(rbs_token_type_str(token.type)));
     VALUE location = rbs_new_location(buffer, token.range);
     VALUE pair = rb_ary_new3(2, type, location);

include/rbs/lexer.h

@@ -134,13 +134,13 @@ typedef struct {
   bool first_token_of_line;       /* This flag is used for tLINECOMMENT */
   unsigned int last_char;         /* Last peeked character */
   const rbs_encoding_t *encoding;
-} lexstate;
+} rbs_lexer_t;
 
 extern rbs_token_t NullToken;
 extern rbs_position_t NullPosition;
 extern rbs_range_t NULL_RANGE;
 
-char *rbs_peek_token(lexstate *state, rbs_token_t tok);
+char *rbs_peek_token(rbs_lexer_t *lexer, rbs_token_t tok);
 int rbs_token_chars(rbs_token_t tok);
 int rbs_token_bytes(rbs_token_t tok);
 
@@ -154,29 +154,29 @@ const char *rbs_token_type_str(enum RBSTokenType type);
 /**
  * Read next character.
  * */
-unsigned int rbs_peek(lexstate *state);
+unsigned int rbs_peek(rbs_lexer_t *lexer);
 
 /**
  * Skip one character.
  * */
-void rbs_skip(lexstate *state);
+void rbs_skip(rbs_lexer_t *lexer);
 
 /**
  * Skip n characters.
  * */
-void rbs_skipn(lexstate *state, size_t size);
+void rbs_skipn(rbs_lexer_t *lexer, size_t size);
 
 /**
  * Return new rbs_token_t with given type.
  * */
-rbs_token_t rbs_next_token(lexstate *state, enum RBSTokenType type);
+rbs_token_t rbs_next_token(rbs_lexer_t *lexer, enum RBSTokenType type);
 
 /**
  * Return new rbs_token_t with EOF type.
  * */
-rbs_token_t rbs_next_eof_token(lexstate *state);
+rbs_token_t rbs_next_eof_token(rbs_lexer_t *lexer);
 
-rbs_token_t rbsparser_next_token(lexstate *state);
+rbs_token_t rbs_lexer_next_token(rbs_lexer_t *lexer);
 
 void rbs_print_token(rbs_token_t tok);
 

include/rbs/parser.h

@@ -44,7 +44,7 @@ typedef struct rbs_error_t {
  * An RBS parser is a LL(3) parser.
  * */
 typedef struct {
-  lexstate *lexstate;
+  rbs_lexer_t *rbs_lexer_t;
 
   rbs_token_t current_token;
   rbs_token_t next_token;       /* The first lookahead token */
@@ -83,14 +83,14 @@ void rbs_parser_push_typevar_table(rbs_parser_t *parser, bool reset);
 NODISCARD bool rbs_parser_insert_typevar(rbs_parser_t *parser, rbs_constant_id_t id);
 
 /**
- * Allocate new lexstate object.
+ * Allocate new rbs_lexer_t object.
  *
  * ```
  * VALUE string = rb_funcall(buffer, rb_intern("content"), 0);
- * rbs_lexer_new(string, 0, 31)    // New lexstate with buffer content
+ * rbs_lexer_new(string, 0, 31)    // New rbs_lexer_t with buffer content
  * ```
  * */
-lexstate *rbs_lexer_new(rbs_allocator_t *, rbs_string_t string, const rbs_encoding_t *encoding, int start_pos, int end_pos);
+rbs_lexer_t *rbs_lexer_new(rbs_allocator_t *, rbs_string_t string, const rbs_encoding_t *encoding, int start_pos, int end_pos);
 
 /**
  * Allocate new rbs_parser_t object.