diff options
Diffstat (limited to 'src/lexer')
| -rw-r--r-- | src/lexer/lexer.c | 136 | ||||
| -rw-r--r-- | src/lexer/lexer.h | 48 |
2 files changed, 184 insertions, 0 deletions
diff --git a/src/lexer/lexer.c b/src/lexer/lexer.c new file mode 100644 index 0000000..7c5ca8f --- /dev/null +++ b/src/lexer/lexer.c @@ -0,0 +1,136 @@ +#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 char peek(struct Lexer* lexer) +{ + return *lexer->current; +} + +static char advance(struct Lexer* lexer) +{ + char c = *lexer->current; + lexer->current += 1; + return c; +} + +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 + 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.source = source; + lexer.current = source; + lexer.line = 1; + return lexer; +} + +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, TOKEN_IDENTIFIER, start); + } + + if (is_digit(character)) + { + while (is_digit(peek(lexer))) + advance(lexer); + return make_token(lexer, TOKEN_INTEGER, start); + } + + switch (character) + { + case '=': return make_token(lexer, TOKEN_EQUAL, start); + case '+': return make_token(lexer, TOKEN_PLUS, start); + case '-': return make_token(lexer, TOKEN_MINUS, start); + case '*': return make_token(lexer, TOKEN_STAR, start); + case '/': return make_token(lexer, 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_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_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_UNKNOWN: return "unknown"; + } + + return "unknown"; +} diff --git a/src/lexer/lexer.h b/src/lexer/lexer.h new file mode 100644 index 0000000..4c40354 --- /dev/null +++ b/src/lexer/lexer.h @@ -0,0 +1,48 @@ +#pragma once + +#include <stddef.h> +#include <stdint.h> + +enum TokenType +{ + TOKEN_EOF, + TOKEN_IDENTIFIER, + TOKEN_INTEGER, + + TOKEN_EQUAL, + TOKEN_PLUS, + TOKEN_MINUS, + TOKEN_STAR, + TOKEN_SLASH, + TOKEN_CARET, + TOKEN_DOT, + TOKEN_COMMA, + TOKEN_COLON, + TOKEN_LEFT_PAREN, + TOKEN_RIGHT_PAREN, + TOKEN_LEFT_BRACKET, + TOKEN_RIGHT_BRACKET, + TOKEN_LEFT_BRACE, + TOKEN_RIGHT_BRACE, + + TOKEN_UNKNOWN, +}; + +struct Token +{ + enum TokenType type; + const char* start; + size_t length; + uint32_t line; +}; + +struct Lexer +{ + const char* source; + const char* current; + uint32_t line; +}; + +struct Lexer create_lexer(const char* source); +struct Token scan_token(struct Lexer* lexer); +const char* token_type_name(enum TokenType type); |