asm/main now tokenises and prints the tokens of a given file

With error checking!

asm/main.cpp

@@ -15,6 +15,8 @@
 #include <iostream>
 #include <optional>
 #include <string>
+#include <tuple>
+#include <vector>
 
 #include <lib/inst.h>
 
@@ -53,4 +55,62 @@ int main(int argc, const char *argv[])
 {
   usage(argv[1], stdout);
   return 0;
+  if (argc == 1 || argc > 3)
+  {
+    usage(argv[0], stderr);
+    return -1;
+  }
+  int ret               = 0;
+  const char *file_name = argv[1];
+  auto file_source      = read_file(file_name);
+
+  string source_str;
+  string_view original;
+  string_view src;
+  vector<token_t> tokens;
+  lerr_t lerr;
+
+  if (file_source.has_value())
+    source_str = file_source.value();
+  else
+  {
+    std::cerr << "ERROR: file `" << file_name << "` does not exist!"
+              << std::endl;
+    ret = -1;
+    goto end;
+  }
+  original = string_view{source_str};
+  src      = string_view{source_str};
+  lerr     = tokenise_buffer(src, tokens);
+
+  if (lerr != lerr_t::OK)
+  {
+    size_t col = 0, line = 1;
+    // TODO: Fix this UB (probably a change in API)
+    auto diff = src.begin() - original.begin();
+    for (auto i = 0; i < diff; ++i)
+    {
+      if (source_str[i] == '\n')
+      {
+        col = 0;
+        ++line;
+      }
+      else
+        ++col;
+    }
+    std::cerr << file_name << ":" << line << ":" << col << ":"
+              << lerr_as_cstr(lerr) << std::endl;
+    ret = 255 - lerr;
+    goto end;
+  }
+  else
+  {
+    for (auto token : tokens)
+    {
+      std::cout << "\t" << token << std::endl;
+    }
+  }
+
+end:
+  return ret;
 }