feat: started project and lexer

include/mrk/common.h

@@ -0,0 +1,19 @@
+#ifndef MRK_COMMON
+#define MRK_COMMON
+
+#include <stdlib.h>
+
+#define MRK_CALLOC(out, n, size)                                               \
+  {                                                                            \
+    void *temp = calloc(n, size);                                              \
+    if (temp == NULL)                                                          \
+      return mrk_err_failed_alloc;                                             \
+    *out = temp;                                                               \
+  }
+
+typedef enum mrk_err {
+  mrk_err_ok = 0,
+  mrk_err_failed_alloc,
+} mrk_err;
+
+#endif

include/mrk/lexer.h

@@ -0,0 +1,51 @@
+#ifndef MRK_LEXER
+#define MRK_LEXER
+
+#include <stdbool.h>
+
+#include "mrk/common.h"
+
+typedef struct mrk_lexer mrk_lexer;
+
+typedef enum mrk_lexer_err {
+  mrk_lexer_err_ok = 0,
+  mrk_lexer_err_done,
+  mrk_lexer_err_unexpected_char,
+} mrk_lexer_err;
+
+typedef enum mrk_token_type {
+  mrk_token_type_pound = 0,
+} mrk_token_type;
+
+typedef struct mrk_token {
+  mrk_token_type type;
+  size_t start;
+  size_t end;
+} mrk_token;
+
+/**
+ * Initialize a new lexer struct.
+ */
+mrk_err mrk_lexer_init(mrk_lexer **out);
+
+/**
+ * Open the buffer with the given lexer struct. `buf` is expected to live for
+ * the duration of the lexing.
+ *
+ * The lexer will run either until `len` characters have been matched, or until
+ * a nul character has been reached. If `len` is set to 0, only the nul check is
+ * used to determine the end of the buffer.
+ */
+void mrk_lexer_open(mrk_lexer *lexer, const char *buf, size_t len);
+
+/**
+ * Returns whether the lexer is done.
+ */
+bool mrk_lexer_at_end(const mrk_lexer *lexer);
+
+/**
+ * Output the next lexed token for the given input.
+ */
+mrk_lexer_err mrk_lexer_next(mrk_token *out, mrk_lexer *lexer);
+
+#endif