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#include <string.h>
#include <stdbool.h>
#include "lexer/lexer.h"
static bool is_alpha(char character)
{
return (character >= 'a' && character <= 'z') ||
(character >= 'A' && character <= 'Z') ||
character == '_';
}
static bool is_digit(char character)
{
return character >= '0' && character <= '9';
}
static bool is_hex_digit(char character)
{
return is_digit(character)
|| (character >= 'a' && character <= 'f')
|| (character >= 'A' && character <= 'F');
}
static enum TokenType identifier_type(const char* start, size_t length)
{
static const struct Keyword
{
const char* text;
size_t length;
enum TokenType type;
} keywords[] =
{
{ "const", 5, TOKEN_CONST },
{ "data", 4, TOKEN_DATA },
{ "proc", 4, TOKEN_PROC },
{ "stack", 5, TOKEN_STACK },
{ "if", 2, TOKEN_IF },
{ "goto", 4, TOKEN_GOTO },
{ "syscall", 7, TOKEN_SYSCALL },
{ "byte", 4, TOKEN_BYTE },
{ "word", 4, TOKEN_WORD },
{ "dword", 5, TOKEN_DWORD },
{ "qword", 5, TOKEN_QWORD },
};
for (size_t i = 0; i < sizeof(keywords) / sizeof(keywords[0]); i += 1)
{
const struct Keyword* keyword = &keywords[i];
if (keyword->length == length && memcmp(start, keyword->text, length) == 0)
return keyword->type;
}
return TOKEN_IDENTIFIER;
}
static char peek(struct Lexer* lexer)
{
return *lexer->current;
}
static char advance(struct Lexer* lexer)
{
char c = *lexer->current;
lexer->current += 1;
return c;
}
static bool match(struct Lexer* lexer, char expected)
{
if (*lexer->current != expected)
return false;
lexer->current += 1;
return true;
}
static void skip_whitespace(struct Lexer* lexer)
{
for (;;)
{
char c = peek(lexer);
if (c == ' ' || c == '\t' || c == '\r')
advance(lexer);
else if (c == '\n')
{
lexer->line += 1;
advance(lexer);
}
else if (c == '/' && lexer->current[1] == '/')
{
while (peek(lexer) != '\n' && peek(lexer) != '\0')
advance(lexer);
}
else if (c == '/' && lexer->current[1] == '*')
{
advance(lexer);
advance(lexer);
while (!(peek(lexer) == '*' && lexer->current[1] == '/') && peek(lexer) != '\0')
{
if (peek(lexer) == '\n')
lexer->line += 1;
advance(lexer);
}
if (peek(lexer) != '\0')
{
advance(lexer);
advance(lexer);
}
}
else
return;
}
}
static struct Token make_token(struct Lexer* lexer, enum TokenType type, const char* start)
{
struct Token token;
token.type = type;
token.start = start;
token.length = (size_t)(lexer->current - start);
token.line = lexer->line;
return token;
}
struct Lexer create_lexer(const char* source)
{
struct Lexer lexer;
lexer.name = NULL;
lexer.source = source;
lexer.current = source;
lexer.line = 1;
return lexer;
}
static struct Token scan_string(struct Lexer* lexer, const char* start)
{
while (peek(lexer) != '"')
{
char character = peek(lexer);
if (character == '\0')
return make_token(lexer, TOKEN_UNKNOWN, start);
if (character == '\n')
lexer->line += 1;
if (character == '\\' && lexer->current[1] != '\0')
advance(lexer);
advance(lexer);
}
advance(lexer);
return make_token(lexer, TOKEN_STRING, start);
}
static struct Token scan_char(struct Lexer* lexer, const char* start)
{
while (peek(lexer) != '\'')
{
char character = peek(lexer);
if (character == '\0' || character == '\n')
return make_token(lexer, TOKEN_UNKNOWN, start);
if (character == '\\' && lexer->current[1] != '\0')
advance(lexer);
advance(lexer);
}
advance(lexer);
return make_token(lexer, TOKEN_CHAR, start);
}
struct Token scan_token(struct Lexer* lexer)
{
skip_whitespace(lexer);
const char* start = lexer->current;
if (peek(lexer) == '\0')
return make_token(lexer, TOKEN_EOF, start);
char character = advance(lexer);
if (is_alpha(character))
{
while (is_alpha(peek(lexer)) || is_digit(peek(lexer)))
advance(lexer);
return make_token(lexer, identifier_type(start, (size_t)(lexer->current - start)), start);
}
if (is_digit(character))
{
if (character == '0' && (peek(lexer) == 'x' || peek(lexer) == 'X'))
{
advance(lexer);
while (is_hex_digit(peek(lexer)))
advance(lexer);
}
else if (character == '0' && (peek(lexer) == 'b' || peek(lexer) == 'B'))
{
advance(lexer);
while (peek(lexer) == '0' || peek(lexer) == '1')
advance(lexer);
}
else
{
while (is_digit(peek(lexer)))
advance(lexer);
}
return make_token(lexer, TOKEN_INTEGER, start);
}
if (character == '"')
return scan_string(lexer, start);
if (character == '\'')
return scan_char(lexer, start);
switch (character)
{
case '=': return make_token(lexer, match(lexer, '=') ? TOKEN_EQUAL_EQUAL : TOKEN_EQUAL, start);
case '!': return make_token(lexer, match(lexer, '=') ? TOKEN_BANG_EQUAL : TOKEN_BANG, start);
case '<': return make_token(lexer, match(lexer, '=') ? TOKEN_LESS_EQUAL : TOKEN_LESS, start);
case '>': return make_token(lexer, match(lexer, '=') ? TOKEN_GREATER_EQUAL : TOKEN_GREATER, start);
case '+': return make_token(lexer, match(lexer, '=') ? TOKEN_PLUS_EQUAL : TOKEN_PLUS, start);
case '-': return make_token(lexer, match(lexer, '=') ? TOKEN_MINUS_EQUAL : TOKEN_MINUS, start);
case '*': return make_token(lexer, match(lexer, '=') ? TOKEN_STAR_EQUAL : TOKEN_STAR, start);
case '/': return make_token(lexer, match(lexer, '=') ? TOKEN_SLASH_EQUAL : TOKEN_SLASH, start);
case '^': return make_token(lexer, TOKEN_CARET, start);
case '.': return make_token(lexer, TOKEN_DOT, start);
case ',': return make_token(lexer, TOKEN_COMMA, start);
case ':': return make_token(lexer, TOKEN_COLON, start);
case '(': return make_token(lexer, TOKEN_LEFT_PAREN, start);
case ')': return make_token(lexer, TOKEN_RIGHT_PAREN, start);
case '[': return make_token(lexer, TOKEN_LEFT_BRACKET, start);
case ']': return make_token(lexer, TOKEN_RIGHT_BRACKET, start);
case '{': return make_token(lexer, TOKEN_LEFT_BRACE, start);
case '}': return make_token(lexer, TOKEN_RIGHT_BRACE, start);
}
return make_token(lexer, TOKEN_UNKNOWN, start);
}
const char* token_type_name(enum TokenType type)
{
switch (type)
{
case TOKEN_EOF: return "eof";
case TOKEN_IDENTIFIER: return "identifier";
case TOKEN_INTEGER: return "integer";
case TOKEN_STRING: return "string";
case TOKEN_CHAR: return "char";
case TOKEN_CONST: return "const";
case TOKEN_DATA: return "data";
case TOKEN_PROC: return "proc";
case TOKEN_STACK: return "stack";
case TOKEN_IF: return "if";
case TOKEN_GOTO: return "goto";
case TOKEN_SYSCALL: return "syscall";
case TOKEN_BYTE: return "byte";
case TOKEN_WORD: return "word";
case TOKEN_DWORD: return "dword";
case TOKEN_QWORD: return "qword";
case TOKEN_EQUAL: return "equal";
case TOKEN_PLUS: return "plus";
case TOKEN_MINUS: return "minus";
case TOKEN_STAR: return "star";
case TOKEN_SLASH: return "slash";
case TOKEN_CARET: return "caret";
case TOKEN_BANG: return "bang";
case TOKEN_LESS: return "less";
case TOKEN_GREATER: return "greater";
case TOKEN_DOT: return "dot";
case TOKEN_COMMA: return "comma";
case TOKEN_COLON: return "colon";
case TOKEN_LEFT_PAREN: return "left_paren";
case TOKEN_RIGHT_PAREN: return "right_paren";
case TOKEN_LEFT_BRACKET: return "left_bracket";
case TOKEN_RIGHT_BRACKET: return "right_bracket";
case TOKEN_LEFT_BRACE: return "left_brace";
case TOKEN_RIGHT_BRACE: return "right_brace";
case TOKEN_EQUAL_EQUAL: return "equal_equal";
case TOKEN_BANG_EQUAL: return "bang_equal";
case TOKEN_PLUS_EQUAL: return "plus_equal";
case TOKEN_MINUS_EQUAL: return "minus_equal";
case TOKEN_STAR_EQUAL: return "star_equal";
case TOKEN_SLASH_EQUAL: return "slash_equal";
case TOKEN_LESS_EQUAL: return "less_equal";
case TOKEN_GREATER_EQUAL: return "greater_equal";
case TOKEN_UNKNOWN: return "unknown";
}
return "unknown";
}
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