krzosa/smallprojects
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Extract lexer and switch token metadata to helpers

Browse Source
This commit is contained in:
Krzosa Karol
2026-05-12 08:42:11 +02:00
parent df7f1f27a1
commit 4cffa1f69a
4 changed files with 336 additions and 330 deletions
Download Patch File Download Diff File Expand all files Collapse all files

232
main.c
View File

@@ -8,206 +8,7 @@
#include <stdarg.h>
#include "base.c"
#include "meta_gen.c"
typedef struct Token {
Token_Kind kind;
char *str;
int len;
char *file;
int line, column;
union {
uint64_t u;
};
} Token;
typedef Vec(Token) Token_Array;
typedef struct Lexer {
char *at;
char *end;
char *file;
int line;
int column;
} Lexer;
void lex_advance(Lexer *lex) {
if (lex->at >= lex->end) {
return;
}
if (*lex->at == '\n') {
lex->line++;
lex->column = 0;
} else {
lex->column++;
}
lex->at += 1;
}
void eat_whitespace(Lexer *lex) {
while (lex->at < lex->end) {
switch (*lex->at) {
case ' ':
case '\t':
case '\r':
case '\n':
lex_advance(lex);
break;
default:
return;
}
}
}
Lexer make_lexer(char *file, char *src, int len) {
Lexer lex = {
.at = src,
.end = src + len,
.file = file,
.line = 0,
.column = 0,
};
return lex;
}
bool lex_peek_is(Lexer *lex, char c) {
return lex->at < lex->end && *lex->at == c;
}
bool lex_match(Lexer *lex, char c) {
if (lex_peek_is(lex, c)) {
lex_advance(lex);
return true;
}
return false;
}
Token_Kind lex_repeat_or_assign(Lexer *lex, char repeated_char, Token_Kind single, Token_Kind repeated, Token_Kind assigned) {
if (lex_match(lex, repeated_char)) return repeated;
if (lex_match(lex, '=')) return assigned;
return single;
}
Token_Kind lex_assign_variant(Lexer *lex, Token_Kind single, Token_Kind assigned) {
return lex_match(lex, '=') ? assigned : single;
}
Token_Kind lex_shift_family(Lexer *lex, char repeated_char, Token_Kind single, Token_Kind single_eq, Token_Kind doubled, Token_Kind doubled_eq) {
if (lex_match(lex, repeated_char)) {
return lex_match(lex, '=') ? doubled_eq : doubled;
}
return lex_match(lex, '=') ? single_eq : single;
}
Token lex_token(Lexer *lex) {
eat_whitespace(lex);
Token t = {
.str = lex->at,
.line = lex->line,
.column = lex->column,
.file = lex->file,
};
if (lex->at >= lex->end) {
t.kind = TOK_EOF;
t.len = 0;
return t;
}
char c = *lex->at;
if (isdigit(c)) {
t.kind = TOK_INT;
while (lex->at < lex->end && isdigit(*lex->at)) {
lex_advance(lex);
}
// @todo: proper lexing of floats (as well as postfixes)
if (lex->at < lex->end && *lex->at == '.') {
t.kind = TOK_FLOAT;
lex_advance(lex);
while (lex->at < lex->end && isdigit(*lex->at)) {
lex_advance(lex);
}
}
if (t.kind == TOK_INT) {
t.u = strtoull(t.str, NULL, 10);
}
t.len = (int)(lex->at - t.str);
return t;
}
lex_advance(lex);
switch (c) {
case 0: t.kind = TOK_EOF; break;
case '(': t.kind = TOK_LPAREN; break;
case ')': t.kind = TOK_RPAREN; break;
case '[': t.kind = TOK_LBRACKET; break;
case ']': t.kind = TOK_RBRACKET; break;
case '{': t.kind = TOK_LBRACE; break;
case '}': t.kind = TOK_RBRACE; break;
case ',': t.kind = TOK_COMMA; break;
case '.': t.kind = TOK_DOT; break;
case ':': t.kind = TOK_COLON; break;
case ';': t.kind = TOK_SEMICOLON; break;
case '?': t.kind = TOK_QUESTION; break;
case '#': t.kind = TOK_HASH; break;
case '+': t.kind = lex_repeat_or_assign(lex, '+', TOK_PLUS, TOK_INC, TOK_PLUS_ASSIGN); break;
case '-': {
if (lex_match(lex, '-')) t.kind = TOK_DEC;
else if (lex_match(lex, '=')) t.kind = TOK_MINUS_ASSIGN;
else if (lex_match(lex, '>')) t.kind = TOK_ARROW;
else t.kind = TOK_MINUS;
} break;
case '*': t.kind = lex_assign_variant(lex, TOK_STAR, TOK_MUL_ASSIGN); break;
case '/': t.kind = lex_assign_variant(lex, TOK_SLASH, TOK_DIV_ASSIGN); break;
case '%': t.kind = lex_assign_variant(lex, TOK_PERCENT, TOK_MOD_ASSIGN); break;
case '=': t.kind = lex_assign_variant(lex, TOK_ASSIGN, TOK_EQ); break;
case '<': t.kind = lex_shift_family(lex, '<', TOK_LT, TOK_LEQ, TOK_LSHIFT, TOK_LSHIFT_ASSIGN); break;
case '>': t.kind = lex_shift_family(lex, '>', TOK_GT, TOK_GEQ, TOK_RSHIFT, TOK_RSHIFT_ASSIGN); break;
case '!': t.kind = lex_assign_variant(lex, TOK_NOT, TOK_NEQ); break;
case '~': t.kind = TOK_BITNOT; break;
case '&': t.kind = lex_repeat_or_assign(lex, '&', TOK_BITAND, TOK_AND, TOK_AND_ASSIGN); break;
case '|': t.kind = lex_repeat_or_assign(lex, '|', TOK_BITOR, TOK_OR, TOK_OR_ASSIGN); break;
case '^': t.kind = lex_assign_variant(lex, TOK_BITXOR, TOK_XOR_ASSIGN); break;
default: {
// @todo: lexer perhaps should have a static buffer of size 1024, error message
// should be put there and piped to the upper program. The token should be filled
// with that message
t.kind = TOK_ERROR;
}
}
t.len = (int)(lex->at - t.str);
return t;
}
void assert_token(Token t, Token_Kind kind, char *text, int line, int column) {
assert(t.kind == kind);
assert(t.line == line);
assert(t.column == column);
assert(t.len == (int)strlen(text));
assert(strncmp(t.str, text, t.len) == 0);
}
Token_Array lex_file(char *file, char *src, int len) {
Lexer lex = make_lexer(file, src, len);
Token_Array result = {0};
for (;;) {
Token token = lex_token(&lex);
vec_push(&result, token);
if (token.kind == TOK_EOF) {
break;
}
}
return result;
}
#include "lex.c"
typedef struct Parser {
Token *at;
@@ -256,7 +57,7 @@ Token *expect_token(Parser *p, Token_Kind kind) {
if (p->at->kind == kind) {
return next_token(p);
}
panicf("expected token kind: %s, got instead: %s", token_to_name[p->at->kind], token_to_name[kind]);
panicf("expected token kind: %s, got instead: %s", token_to_name(p->at->kind), token_to_name(kind));
}
Ast *create_ast(Token *token, Ast_Kind kind) {
@@ -287,7 +88,7 @@ Ast *parse_atom(Parser *p) {
n = parse_expr(p, 0);
expect_token(p, TOK_RPAREN);
} else {
panicf("unknown token in %s. %.*s (%s/%d), ", __FUNCTION__, token->len, token->str, token_to_name[token->kind], token->kind);
panicf("unknown token in %s. %.*s (%s/%d), ", __FUNCTION__, token->len, token->str, token_to_name(token->kind), token->kind);
}
return n;
}
@@ -315,7 +116,7 @@ Ast *parse_valid_left_binding(Parser *p, Token *tok, Ast *left) {
case TOK_BITOR: case TOK_BITXOR: case TOK_AND: case TOK_OR: case TOK_LSHIFT: case TOK_RSHIFT: {
return create_binary_expr(tok, tok->kind, left, parse_expr(p, get_binding_power(tok)));
} break;
default: panicf("unknown token in %s. %.*s (%s/%d), ", __FUNCTION__, tok->len, tok->str, token_to_name[tok->kind], tok->kind);
default: panicf("unknown token in %s. %.*s (%s/%d), ", __FUNCTION__, tok->len, tok->str, token_to_name(tok->kind), tok->kind);
}
return NULL;
}
@@ -366,7 +167,7 @@ void print_expr(Ast *n) {
case AST_INT: printf("%lu", n->u); break;
case AST_BINARY: {
print_expr(n->l);
printf(" %s ", token_to_op[n->op]);
printf(" %s ", token_to_op(n->op));
print_expr(n->r);
} break;
default: panicf("encountered invalid ast kind in %s of kind: %d\n", __FUNCTION__, n->kind);
@@ -415,18 +216,17 @@ void parser_test(void) {
TEST_EVAL((2+3)*(4+5));
TEST_EVAL(9>3&1);
TEST_EVAL(8|1<4);
// TEST_EVAL(7<=3+4);
// TEST_EVAL(8>=2*4);
// TEST_EVAL(4==2+2);
// TEST_EVAL(5!=2+2);
// TEST_EVAL(1&&2);
// TEST_EVAL(0||3);
// TEST_EVAL(1||0&&0);
// TEST_EVAL(8<<2);
// TEST_EVAL(32>>3);
// TEST_EVAL(1+2<<3);
// TEST_EVAL(16>>1+1);
TEST_EVAL(7<=3+4);
TEST_EVAL(8>=2*4);
TEST_EVAL(4==2+2);
TEST_EVAL(5!=2+2);
TEST_EVAL(1&&2);
TEST_EVAL(0||3);
TEST_EVAL(1||0&&0);
TEST_EVAL(8<<2);
TEST_EVAL(32>>3);
TEST_EVAL(1+2<<3);
TEST_EVAL(16>>1+1);
#pragma clang diagnostic pop