lexer.h

#ifndef LEXER_H
#define LEXER_H

#include "types.h"
#include "idtable.h"

enum TokenType {
 	TOKEN_UNKNOWN = 0, TOKEN_BEGIN, TOKEN_END, TOKEN_ID,		/* 0 - 3 */
	TOKEN_ASSIGNMENT, TOKEN_NUMBER, TOKEN_SEMICOLON,			/* 4 - 6 */
	TOKEN_AND, TOKEN_OR, TOKEN_NOT, TOKEN_LT, TOKEN_EQ,			/* 7 - 11 */
	TOKEN_GT, TOKEN_LTE, TOKEN_GTE,	TOKEN_PLUS,					/* 12 - 14 */
	TOKEN_MINUS, TOKEN_STAR, TOKEN_SLASH, TOKEN_LEFTBRACKET,	/* 15 - 18 */
	TOKEN_RIGHTBRACKET, TOKEN_WHILE, TOKEN_DO, TOKEN_IF,		/* 19 - 22 */
	TOKEN_THEN, TOKEN_ELSE,	TOKEN_EOF, TOKEN_CALL, TOKEN_PRINT,	/* 23 - 28 */
	TOKEN_INTREAD, TOKEN_READ, TOKEN_STRING, TOKEN_FUNCTION,	/* 29 - 32 */
	TOKEN_COMMA, TOKEN_LOCAL, TOKEN_RETURN, TOKEN_ARRAY,		/* 33 - 36 */
	TOKEN_LEFT_SQUARE_BRACKET, TOKEN_RIGHT_SQUARE_BRACKET,		/* 37 - 38 */
	TOKEN_DOT, TOKEN_FIELD, TOKEN_OBJECT, TOKEN_INCLUDE,		/* 39 - 42 */
	TOKEN_NEW, TOKEN_LOAD
};

extern char* token_name[];

#define MAX_TOKEN_SIZE		255
#define READ_BUF_SIZE	4096
#define COMMENT_CHAR	'#'


typedef struct {
	enum TokenType	type;
	int				line_num;
	Value*			value; /* For constants - value, for ids - index in id table */
} Token;

typedef struct {
	FILE* stream;
	char stream_buffer[READ_BUF_SIZE];
	char token_buffer[MAX_TOKEN_SIZE];
	IDTable* id_table;
	int head;
	int absolute_head_position;
	int buffer_size;
	int line_num;
	int field_name_following;
} LexerState;

void StartLexer(LexerState *lex, const char *filename, IDTable *id_table);
void StopLexer(LexerState *lex);
Token GetNextToken(LexerState *lex);
int HasNextToken(LexerState *lex);

#endif /* LEXER_H */