Merge branch 'debugger'

This add a very basic implementation of debug info. Right now the only info
that this command will find are global function names. The plan is to first
parse table syntax, ie. `foo.bar.baz`, and actually go down the stack until
we react that `baz` function of table bar of table foo. Next would be
ordered tables since that will be a bit more trick which the name tables are
similar to just the `laco_line_to_words` only with dots instead of spaces.

Author: sourrust

src/CMakeLists.txt

@@ -4,6 +4,7 @@ include_directories("${laco_SOURCE_DIR}/src" "${DEPS_DIR}/linenoise")
 
 set(SOURCE ${DEPS_DIR}/linenoise/linenoise.c
            main.c util.c util/print.c
+           commands/debugger.c
            flags.c commands.c laco.c)
 
 add_executable(laco ${SOURCE})

src/commands.c

@@ -2,16 +2,23 @@
 
 #include <stdbool.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
 #include "util.h"
+#include "commands/debugger.h"
 
 static const char* quit_matches[] = {"quit", "q"};
 static const char* help_matches[] = {"help", "?"};
 
+/* Debugger commands */
+static const char* debug_info_matches[] = {"info"};
+
 static void print_commands_help() {
   puts("  Commands available:\n");
-  puts("    :quit, :q  \tExit laco");
-  puts("    :help, :?  \tDisplay this list of commands");
+  puts("    :quit, :q     \tExit laco");
+  puts("    :help, :?     \tDisplay this list of commands");
+  puts("    :info <name>  \tShow information on given function");
 }
 
 static inline bool is_quit(const char* command) {
@@ -22,17 +29,31 @@ static inline bool is_help(const char* command) {
   return laco_is_match(help_matches, command);
 }
 
+static inline bool is_debug_info(const char* command) {
+  return laco_is_match(debug_info_matches, command);
+}
+
 void laco_handle_command(struct LacoState* laco, char* line) {
   if(laco != NULL && line != NULL) {
-    const char* command = line + 1;
+    char* command_line   = strdup(line + 1);
+    char** command_words = laco_line_to_words(command_line);
+
+    /* Alias for  */
+    const char* command    = command_words[0];
+    const char** arguments = (const char**) command_words + 1;
 
     if(is_quit(command)) {
       laco_kill(laco, 0, "Exiting laco...");
     } else if(is_help(command))  {
       print_commands_help();
+    } else if(is_debug_info(command)) {
+      laco_print_debug_info(laco, arguments[0]);
     }
 
-    /* Make it seem like this was an empty line */
+    free(command_line);
+    free(command_words);
+
+    /* Make it seems like this was an empty line */
     line[0] = '\0';
   }
 }

src/commands/debugger.c

@@ -0,0 +1,24 @@
+#include "debugger.h"
+
+#include <stdio.h>
+#include <lua.h>
+
+#include "laco.h"
+
+void laco_print_debug_info(struct LacoState* laco,
+                           const char* function_name) {
+  lua_State* L = laco_get_laco_lua_state(laco);
+  lua_Debug debug_info = {0};
+
+  lua_getfield(L, LUA_GLOBALSINDEX, function_name);
+
+  lua_getinfo(L, ">Sl", &debug_info);
+
+  printf(
+    "What:            \t%s\n"
+    "Source file:     \t%s\n"
+    "Line defined on: \t%d\n"
+    "Current line:    \t%d\n",
+    debug_info.what, debug_info.source,
+    debug_info.linedefined, debug_info.currentline);
+}

src/commands/debugger.h

@@ -0,0 +1,12 @@
+#ifndef LACO_DEBUGGER_H
+#define LACO_DEBUGGER_H
+
+struct LacoState;
+
+/**
+ * Prints out debug info of a give function name.
+ */
+void laco_print_debug_info(struct LacoState* laco,
+                           const char* function_name);
+
+#endif /* LACO_DEBUGGER_H */

src/util.c

@@ -100,6 +100,14 @@ static bool pushline(LacoState* laco, bool isFirstLine) {
   return result;
 }
 
+static inline void ignore_extra_spaces(char** string_ptr) {
+  if(*string_ptr == NULL) return;
+
+  while(**string_ptr == ' ') {
+    *string_ptr += 1;
+  }
+}
+
 /* External API */
 
 int laco_load_line(LacoState* laco) {
@@ -170,3 +178,22 @@ int laco_is_match(const char** matches, const char* test_string) {
 
   return false;
 }
+
+char** laco_line_to_words(char* line) {
+  if(line == NULL) return NULL;
+
+  char** result = calloc(16, sizeof(char*));
+  size_t i = 0;
+
+  while(1) {
+    result[i] = strsep(&line, " ");
+
+    if(result[i] == NULL) break;
+
+    ignore_extra_spaces(&line);
+
+    i += 1;
+  }
+
+  return result;
+}

src/util.h

@@ -38,4 +38,10 @@ void laco_report_error(struct LacoState* laco, int status);
  */
 int laco_is_match(const char** matches, const char* test_string);
 
+/**
+ * Takes a line, seperated by spaces, and changes it into an array of the
+ * words that make up the line. The last value of this array will be NULL.
+ */
+char** laco_line_to_words(char* line);
+
 #endif /* LACO_UTIL_H */