Refactored the C files out into libraries, started work on the BASIC repl (it can sorta do math!)

src/basic.h

@@ -0,0 +1,39 @@
+#ifndef _BASIC_H_
+#define _BASIC_H_
+
+#define BASIC_MATH_ADD 1
+#define BASIC_MATH_SUB 2
+#define BASIC_MATH_MUL 3
+#define BASIC_MATH_DIV 4
+#define BASIC_MATH_MOD 5
+
+#define BASIC_LVAL_EXPR  0
+#define BASIC_LVAL_VAR   1
+#define BASIC_RVAL_EXPR  2
+#define BASIC_RVAL_VAR   3
+#define BASIC_RVAL_CONST 4
+
+#define BASIC_FOUND_LVAL 0x0001
+#define BASIC_FOUND_RVAL 0x0002
+
+#define BASIC_ERR_SYNTAX_MULTIPLE_LVALUES 1
+#define BASIC_ERR_SYNTAX_TOKEN_LENGTH 2
+#define BASIC_ERR_SYNTAX_GENERAL 3
+#define BASIC_ERR_SYNTAX_MULTIPLE_RVALUES 4
+
+#define BASIC_TOKENIZER_MAX_LENGTH 512
+
+struct basic_math_expr {
+  char type;
+  char lval_type;
+  char rval_type;
+  char pad;
+  void *lval;
+  void *rval;
+};
+
+extern int basic_errno;
+
+void run_basic(void);
+
+#endif /* _BASIC_H_ */