Add rudimentary error checks and reformat comments

There were a number of functions assigning their return value to
`error` without much explanation.  I added in some rudimentary
error checking to help flesh out the example.

Also, I reformatted all of the comments down to 80 cols (and in
some cases, slightly updated the wording).

examples/general.c

@@ -1,19 +1,20 @@
-// [**libgit2**][lg] is a portable, pure C implementation of the Git core methods
+// [**libgit2**][lg] is a portable, pure C implementation of the Git core
-// provided as a re-entrant linkable library with a solid API, allowing you
+// methods provided as a re-entrant linkable library with a solid API,
-// to write native speed custom Git applications in any language which
+// allowing you to write native speed custom Git applications in any
-// supports C bindings.
+// language which supports C bindings.
 //
 // This file is an example of using that API in a real, compilable C file.
-// As the API is updated, this file will be updated to demonstrate the
+// As the API is updated, this file will be updated to demonstrate the new
-// new functionality.
+// functionality.
 //
-// If you're trying to write something in C using [libgit2][lg], you will also want
+// If you're trying to write something in C using [libgit2][lg], you should
-// to check out the generated [API documentation][ap]. We've
+// also check out the generated [API documentation][ap]. We try to link to
-// tried to link to the relevant sections of the API docs in each section in this file.
+// the relevant sections of the API docs in each section in this file.
 //
-// **libgit2** only implements the core plumbing functions, not really the higher
+// **libgit2** (for the most part) only implements the core plumbing
-// level porcelain stuff. For a primer on Git Internals that you will need to know
+// functions, not really the higher level porcelain stuff. For a primer on
-// to work with Git at this level, check out [Chapter 9][pg] of the Pro Git book.
+// Git Internals that you will need to know to work with Git at this level,
+// check out [Chapter 9][pg] of the Pro Git book.
 //
 // [lg]: http://libgit2.github.com
 // [ap]: http://libgit2.github.com/libgit2
@@ -21,43 +22,63 @@
 
 // ### Includes
 
-// Including the `git2.h` header will include all the other libgit2 headers that you need.
+// Including the `git2.h` header will include all the other libgit2 headers
-// It should be the only thing you need to include in order to compile properly and get
+// that you need.  It should be the only thing you need to include in order
-// all the libgit2 API.
+// to compile properly and get all the libgit2 API.
 #include <git2.h>
 #include <stdio.h>
 
+// Almost all libgit2 functions return 0 on success or negative on error.
+// This is not production quality error checking, but should be sufficient
+// as an example.
+static void check_error(int error_code, const char *action)
+{
+	if (!error_code)
+		return;
+
+	const git_error *error = giterr_last();
+
+	printf("Error %d %s - %s\n", error_code, action,
+		   (error && error->message) ? error->message : "???");
+
+	exit(1);
+}
+
 int main (int argc, char** argv)
 {
   // ### Opening the Repository
 
-  // There are a couple of methods for opening a repository, this being the simplest.
+  // There are a couple of methods for opening a repository, this being the
-  // There are also [methods][me] for specifying the index file and work tree locations, here
+  // simplest.  There are also [methods][me] for specifying the index file
-  // we are assuming they are in the normal places.
+  // and work tree locations, here we assume they are in the normal places.
   //
   // [me]: http://libgit2.github.com/libgit2/#HEAD/group/repository
+  int error;
+  const char *repo_path = (argc > 1) ? argv[1] : "/opt/libgit2-test/.git";
   git_repository *repo;
-  if (argc > 1) {
+
-    git_repository_open(&repo, argv[1]);
+  error = git_repository_open(&repo, repo_path);
-  } else {
+  check_error(error, "opening repository");
-    git_repository_open(&repo, "/opt/libgit2-test/.git");
-  }
 
   // ### SHA-1 Value Conversions
 
-  // For our first example, we will convert a 40 character hex value to the 20 byte raw SHA1 value.
+  // For our first example, we will convert a 40 character hex value to the
+  // 20 byte raw SHA1 value.
   printf("*Hex to Raw*\n");
   char hex[] = "fd6e612585290339ea8bf39c692a7ff6a29cb7c3";
 
-  // The `git_oid` is the structure that keeps the SHA value. We will use this throughout the example
+  // The `git_oid` is the structure that keeps the SHA value. We will use
-  // for storing the value of the current SHA key we're working with.
+  // this throughout the example for storing the value of the current SHA
+  // key we're working with.
   git_oid oid;
   git_oid_fromstr(&oid, hex);
 
-  // Once we've converted the string into the oid value, we can get the raw value of the SHA.
+  // Once we've converted the string into the oid value, we can get the raw
+  // value of the SHA.
   printf("Raw 20 bytes: [%.20s]\n", (&oid)->id);
 
-  // Next we will convert the 20 byte raw SHA1 value to a human readable 40 char hex value.
+  // Next we will convert the 20 byte raw SHA1 value to a human readable 40
+  // char hex value.
   printf("\n*Raw to Hex*\n");
   char out[41];
   out[40] = '\0';
@@ -67,10 +88,12 @@ int main (int argc, char** argv)
   printf("SHA hex string: %s\n", out);
 
   // ### Working with the Object Database
-  // **libgit2** provides [direct access][odb] to the object database.
+
-  // The object database is where the actual objects are stored in Git. For
+  // **libgit2** provides [direct access][odb] to the object database.  The
+  // object database is where the actual objects are stored in Git. For
   // working with raw objects, we'll need to get this structure from the
   // repository.
+  //
   // [odb]: http://libgit2.github.com/libgit2/#HEAD/group/odb
   git_odb *odb;
   git_repository_odb(&odb, repo);
@@ -82,55 +105,60 @@ int main (int argc, char** argv)
   git_otype otype;
   const unsigned char *data;
   const char *str_type;
-  int error;
 
-  // We can read raw objects directly from the object database if we have the oid (SHA)
+  // We can read raw objects directly from the object database if we have
-  // of the object.  This allows us to access objects without knowing thier type and inspect
+  // the oid (SHA) of the object.  This allows us to access objects without
-  // the raw bytes unparsed.
+  // knowing thier type and inspect the raw bytes unparsed.
   error = git_odb_read(&obj, odb, &oid);
+  check_error(error, "finding object in repository");
 
-  // A raw object only has three properties - the type (commit, blob, tree or tag), the size
+  // A raw object only has three properties - the type (commit, blob, tree
-  // of the raw data and the raw, unparsed data itself.  For a commit or tag, that raw data
+  // or tag), the size of the raw data and the raw, unparsed data itself.
-  // is human readable plain ASCII text. For a blob it is just file contents, so it could be
+  // For a commit or tag, that raw data is human readable plain ASCII
-  // text or binary data. For a tree it is a special binary format, so it's unlikely to be
+  // text. For a blob it is just file contents, so it could be text or
-  // hugely helpful as a raw object.
+  // binary data. For a tree it is a special binary format, so it's unlikely
+  // to be hugely helpful as a raw object.
   data = (const unsigned char *)git_odb_object_data(obj);
   otype = git_odb_object_type(obj);
 
-  // We provide methods to convert from the object type which is an enum, to a string
+  // We provide methods to convert from the object type which is an enum, to
-  // representation of that value (and vice-versa).
+  // a string representation of that value (and vice-versa).
   str_type = git_object_type2string(otype);
   printf("object length and type: %d, %s\n",
       (int)git_odb_object_size(obj),
       str_type);
 
-  // For proper memory management, close the object when you are done with it or it will leak
+  // For proper memory management, close the object when you are done with
-  // memory.
+  // it or it will leak memory.
   git_odb_object_free(obj);
 
   // #### Raw Object Writing
 
   printf("\n*Raw Object Write*\n");
 
-  // You can also write raw object data to Git. This is pretty cool because it gives you
+  // You can also write raw object data to Git. This is pretty cool because
-  // direct access to the key/value properties of Git.  Here we'll write a new blob object
+  // it gives you direct access to the key/value properties of Git.  Here
-  // that just contains a simple string.  Notice that we have to specify the object type as
+  // we'll write a new blob object that just contains a simple string.
-  // the `git_otype` enum.
+  // Notice that we have to specify the object type as the `git_otype` enum.
   git_odb_write(&oid, odb, "test data", sizeof("test data") - 1, GIT_OBJ_BLOB);
 
-  // Now that we've written the object, we can check out what SHA1 was generated when the
+  // Now that we've written the object, we can check out what SHA1 was
-  // object was written to our database.
+  // generated when the object was written to our database.
   git_oid_fmt(out, &oid);
   printf("Written Object: %s\n", out);
 
   // ### Object Parsing
-  // libgit2 has methods to parse every object type in Git so you don't have to work directly
+
-  // with the raw data. This is much faster and simpler than trying to deal with the raw data
+  // libgit2 has methods to parse every object type in Git so you don't have
-  // yourself.
+  // to work directly with the raw data. This is much faster and simpler
+  // than trying to deal with the raw data yourself.
 
   // #### Commit Parsing
-  // [Parsing commit objects][pco] is simple and gives you access to all the data in the commit
+
-  // - the // author (name, email, datetime), committer (same), tree, message, encoding and parent(s).
+  // [Parsing commit objects][pco] is simple and gives you access to all the
+  // data in the commit - the author (name, email, datetime), committer
+  // (same), tree, message, encoding and parent(s).
+  //
   // [pco]: http://libgit2.github.com/libgit2/#HEAD/group/commit
 
   printf("\n*Commit Parsing*\n");
@@ -139,27 +167,31 @@ int main (int argc, char** argv)
   git_oid_fromstr(&oid, "f0877d0b841d75172ec404fc9370173dfffc20d1");
 
   error = git_commit_lookup(&commit, repo, &oid);
+  check_error(error, "looking up commit");
 
   const git_signature *author, *cmtter;
   const char *message;
   time_t ctime;
   unsigned int parents, p;
 
-  // Each of the properties of the commit object are accessible via methods, including commonly
+  // Each of the properties of the commit object are accessible via methods,
-  // needed variations, such as `git_commit_time` which returns the author time and `_message`
+  // including commonly needed variations, such as `git_commit_time` which
-  // which gives you the commit message.
+  // returns the author time and `git_commit_message` which gives you the
+  // commit message (as a NUL-terminated string).
   message  = git_commit_message(commit);
   author   = git_commit_author(commit);
   cmtter   = git_commit_committer(commit);
   ctime    = git_commit_time(commit);
 
-  // The author and committer methods return [git_signature] structures, which give you name, email
+  // The author and committer methods return [git_signature] structures,
-  // and `when`, which is a `git_time` structure, giving you a timestamp and timezone offset.
+  // which give you name, email and `when`, which is a `git_time` structure,
+  // giving you a timestamp and timezone offset.
   printf("Author: %s (%s)\n", author->name, author->email);
 
-  // Commits can have zero or more parents. The first (root) commit will have no parents, most commits
+  // Commits can have zero or more parents. The first (root) commit will
-  // will have one, which is the commit it was based on, and merge commits will have two or more.
+  // have no parents, most commits will have one (i.e. the commit it was
-  // Commits can technically have any number, though it's pretty rare to have more than two.
+  // based on) and merge commits will have two or more.  Commits can
+  // technically have any number, though it's rare to have more than two.
   parents  = git_commit_parentcount(commit);
   for (p = 0;p < parents;p++) {
     git_commit *parent;
@@ -169,15 +201,17 @@ int main (int argc, char** argv)
     git_commit_free(parent);
   }
 
-  // Don't forget to close the object to prevent memory leaks. You will have to do this for
+  // Don't forget to close the object to prevent memory leaks. You will have
-  // all the objects you open and parse.
+  // to do this for all the objects you open and parse.
   git_commit_free(commit);
 
   // #### Writing Commits
+
+  // libgit2 provides a couple of methods to create commit objects easily as
+  // well. There are four different create signatures, we'll just show one
+  // of them here.  You can read about the other ones in the [commit API
+  // docs][cd].
   //
-  // libgit2 provides a couple of methods to create commit objects easily as well. There are four
-  // different create signatures, we'll just show one of them here.  You can read about the other
-  // ones in the [commit API docs][cd].
   // [cd]: http://libgit2.github.com/libgit2/#HEAD/group/commit
 
   printf("\n*Commit Writing*\n");
@@ -185,24 +219,27 @@ int main (int argc, char** argv)
   git_tree *tree;
   git_commit *parent;
 
-  // Creating signatures for an authoring identity and time is pretty simple - you will need to have
+  // Creating signatures for an authoring identity and time is simple.  You
-  // this to create a commit in order to specify who created it and when.  Default values for the name
+  // will need to do this to specify who created a commit and when.  Default
-  // and email should be found in the `user.name` and `user.email` configuration options.  See the `config`
+  // values for the name and email should be found in the `user.name` and
-  // section of this example file to see how to access config values.
+  // `user.email` configuration options.  See the `config` section of this
-  git_signature_new((git_signature **)&author, "Scott Chacon", "schacon@gmail.com",
+  // example file to see how to access config values.
-      123456789, 60);
+  git_signature_new((git_signature **)&author,
-  git_signature_new((git_signature **)&cmtter, "Scott A Chacon", "scott@github.com",
+      "Scott Chacon", "schacon@gmail.com", 123456789, 60);
-      987654321, 90);
+  git_signature_new((git_signature **)&cmtter,
+      "Scott A Chacon", "scott@github.com", 987654321, 90);
 
-  // Commit objects need a tree to point to and optionally one or more parents.  Here we're creating oid
+  // Commit objects need a tree to point to and optionally one or more
-  // objects to create the commit with, but you can also use
+  // parents.  Here we're creating oid objects to create the commit with,
+  // but you can also use
   git_oid_fromstr(&tree_id, "28873d96b4e8f4e33ea30f4c682fd325f7ba56ac");
   git_tree_lookup(&tree, repo, &tree_id);
   git_oid_fromstr(&parent_id, "f0877d0b841d75172ec404fc9370173dfffc20d1");
   git_commit_lookup(&parent, repo, &parent_id);
 
-  // Here we actually create the commit object with a single call with all the values we need to create
+  // Here we actually create the commit object with a single call with all
-  // the commit.  The SHA key is written to the `commit_id` variable here.
+  // the values we need to create the commit.  The SHA key is written to the
+  // `commit_id` variable here.
   git_commit_create_v(
     &commit_id, /* out id */
     repo,
@@ -219,35 +256,42 @@ int main (int argc, char** argv)
   printf("New Commit: %s\n", out);
 
   // #### Tag Parsing
-  // You can parse and create tags with the [tag management API][tm], which functions very similarly
+
-  // to the commit lookup, parsing and creation methods, since the objects themselves are very similar.
+  // You can parse and create tags with the [tag management API][tm], which
+  // functions very similarly to the commit lookup, parsing and creation
+  // methods, since the objects themselves are very similar.
+  //
   // [tm]: http://libgit2.github.com/libgit2/#HEAD/group/tag
   printf("\n*Tag Parsing*\n");
   git_tag *tag;
   const char *tmessage, *tname;
   git_otype ttype;
 
-  // We create an oid for the tag object if we know the SHA and look it up in the repository the same
+  // We create an oid for the tag object if we know the SHA and look it up
-  // way that we would a commit (or any other) object.
+  // the same way that we would a commit (or any other object).
   git_oid_fromstr(&oid, "bc422d45275aca289c51d79830b45cecebff7c3a");
 
   error = git_tag_lookup(&tag, repo, &oid);
+  check_error(error, "looking up tag");
 
-  // Now that we have the tag object, we can extract the information it generally contains: the target
+  // Now that we have the tag object, we can extract the information it
-  // (usually a commit object), the type of the target object (usually 'commit'), the name ('v1.0'),
+  // generally contains: the target (usually a commit object), the type of
-  // the tagger (a git_signature - name, email, timestamp), and the tag message.
+  // the target object (usually 'commit'), the name ('v1.0'), the tagger (a
+  // git_signature - name, email, timestamp), and the tag message.
   git_tag_target((git_object **)&commit, tag);
-  tname = git_tag_name(tag);    // "test"
+  tname = git_tag_name(tag);		// "test"
-  ttype = git_tag_target_type(tag);    // GIT_OBJ_COMMIT (otype enum)
+  ttype = git_tag_target_type(tag);	// GIT_OBJ_COMMIT (otype enum)
-  tmessage = git_tag_message(tag); // "tag message\n"
+  tmessage = git_tag_message(tag);	// "tag message\n"
   printf("Tag Message: %s\n", tmessage);
 
   git_commit_free(commit);
 
   // #### Tree Parsing
-  // [Tree parsing][tp] is a bit different than the other objects, in that we have a subtype which is the
+
-  // tree entry.  This is not an actual object type in Git, but a useful structure for parsing and
+  // [Tree parsing][tp] is a bit different than the other objects, in that
-  // traversing tree entries.
+  // we have a subtype which is the tree entry.  This is not an actual
+  // object type in Git, but a useful structure for parsing and traversing
+  // tree entries.
   //
   // [tp]: http://libgit2.github.com/libgit2/#HEAD/group/tree
   printf("\n*Tree Parsing*\n");
@@ -259,31 +303,36 @@ int main (int argc, char** argv)
   git_oid_fromstr(&oid, "2a741c18ac5ff082a7caaec6e74db3075a1906b5");
   git_tree_lookup(&tree, repo, &oid);
 
-  // Getting the count of entries in the tree so you can iterate over them if you want to.
+  // Getting the count of entries in the tree so you can iterate over them
+  // if you want to.
   size_t cnt = git_tree_entrycount(tree); // 3
   printf("tree entries: %d\n", (int)cnt);
 
   entry = git_tree_entry_byindex(tree, 0);
   printf("Entry name: %s\n", git_tree_entry_name(entry)); // "hello.c"
 
-  // You can also access tree entries by name if you know the name of the entry you're looking for.
+  // You can also access tree entries by name if you know the name of the
+  // entry you're looking for.
   entry = git_tree_entry_byname(tree, "hello.c");
   git_tree_entry_name(entry); // "hello.c"
 
-  // Once you have the entry object, you can access the content or subtree (or commit, in the case
+  // Once you have the entry object, you can access the content or subtree
-  // of submodules) that it points to.  You can also get the mode if you want.
+  // (or commit, in the case of submodules) that it points to.  You can also
+  // get the mode if you want.
   git_tree_entry_to_object(&objt, repo, entry); // blob
 
   // Remember to close the looked-up object once you are done using it
   git_object_free(objt);
 
   // #### Blob Parsing
-  //
+
-  // The last object type is the simplest and requires the least parsing help. Blobs are just file
+  // The last object type is the simplest and requires the least parsing
-  // contents and can contain anything, there is no structure to it. The main advantage to using the
+  // help. Blobs are just file contents and can contain anything, there is
-  // [simple blob api][ba] is that when you're creating blobs you don't have to calculate the size
+  // no structure to it. The main advantage to using the [simple blob
-  // of the content.  There is also a helper for reading a file from disk and writing it to the db and
+  // api][ba] is that when you're creating blobs you don't have to calculate
-  // getting the oid back so you don't have to do all those steps yourself.
+  // the size of the content.  There is also a helper for reading a file
+  // from disk and writing it to the db and getting the oid back so you
+  // don't have to do all those steps yourself.
   //
   // [ba]: http://libgit2.github.com/libgit2/#HEAD/group/blob
 
@@ -294,19 +343,21 @@ int main (int argc, char** argv)
   git_blob_lookup(&blob, repo, &oid);
 
   // You can access a buffer with the raw contents of the blob directly.
-  // Note that this buffer may not be contain ASCII data for certain blobs (e.g. binary files):
+  // Note that this buffer may not be contain ASCII data for certain blobs
-  // do not consider the buffer a NULL-terminated string, and use the `git_blob_rawsize` attribute to
+  // (e.g. binary files): do not consider the buffer a NULL-terminated
-  // find out its exact size in bytes
+  // string, and use the `git_blob_rawsize` attribute to find out its exact
+  // size in bytes
   printf("Blob Size: %ld\n", (long)git_blob_rawsize(blob)); // 8
   git_blob_rawcontent(blob); // "content"
 
   // ### Revwalking
-  //
+
-  // The libgit2 [revision walking api][rw] provides methods to traverse the directed graph created
+  // The libgit2 [revision walking api][rw] provides methods to traverse the
-  // by the parent pointers of the commit objects.  Since all commits point back to the commit that
+  // directed graph created by the parent pointers of the commit objects.
-  // came directly before them, you can walk this parentage as a graph and find all the commits that
+  // Since all commits point back to the commit that came directly before
-  // were ancestors of (reachable from) a given starting point.  This can allow you to create `git log`
+  // them, you can walk this parentage as a graph and find all the commits
-  // type functionality.
+  // that were ancestors of (reachable from) a given starting point.  This
+  // can allow you to create `git log` type functionality.
   //
   // [rw]: http://libgit2.github.com/libgit2/#HEAD/group/revwalk
 
@@ -316,11 +367,13 @@ int main (int argc, char** argv)
 
   git_oid_fromstr(&oid, "f0877d0b841d75172ec404fc9370173dfffc20d1");
 
-  // To use the revwalker, create a new walker, tell it how you want to sort the output and then push
+  // To use the revwalker, create a new walker, tell it how you want to sort
-  // one or more starting points onto the walker.  If you want to emulate the output of `git log` you
+  // the output and then push one or more starting points onto the walker.
-  // would push the SHA of the commit that HEAD points to into the walker and then start traversing them.
+  // If you want to emulate the output of `git log` you would push the SHA
-  // You can also 'hide' commits that you want to stop at or not see any of their ancestors.  So if you
+  // of the commit that HEAD points to into the walker and then start
-  // want to emulate `git log branch1..branch2`, you would push the oid of `branch2` and hide the oid
+  // traversing them.  You can also 'hide' commits that you want to stop at
+  // or not see any of their ancestors.  So if you want to emulate `git log
+  // branch1..branch2`, you would push the oid of `branch2` and hide the oid
   // of `branch1`.
   git_revwalk_new(&walk, repo);
   git_revwalk_sorting(walk, GIT_SORT_TOPOLOGICAL | GIT_SORT_REVERSE);
@@ -329,28 +382,32 @@ int main (int argc, char** argv)
   const git_signature *cauth;
   const char *cmsg;
 
-  // Now that we have the starting point pushed onto the walker, we can start asking for ancestors. It
+  // Now that we have the starting point pushed onto the walker, we start
-  // will return them in the sorting order we asked for as commit oids.
+  // asking for ancestors. It will return them in the sorting order we asked
-  // We can then lookup and parse the commited pointed at by the returned OID;
+  // for as commit oids.  We can then lookup and parse the commited pointed
-  // note that this operation is specially fast since the raw contents of the commit object will
+  // at by the returned OID; note that this operation is specially fast
-  // be cached in memory
+  // since the raw contents of the commit object will be cached in memory
   while ((git_revwalk_next(&oid, walk)) == 0) {
     error = git_commit_lookup(&wcommit, repo, &oid);
+	check_error(error, "looking up commit during revwalk");
+
     cmsg  = git_commit_message(wcommit);
     cauth = git_commit_author(wcommit);
     printf("%s (%s)\n", cmsg, cauth->email);
+
     git_commit_free(wcommit);
   }
 
-  // Like the other objects, be sure to free the revwalker when you're done to prevent memory leaks.
+  // Like the other objects, be sure to free the revwalker when you're done
-  // Also, make sure that the repository being walked it not deallocated while the walk is in
+  // to prevent memory leaks.  Also, make sure that the repository being
-  // progress, or it will result in undefined behavior
+  // walked it not deallocated while the walk is in progress, or it will
+  // result in undefined behavior
   git_revwalk_free(walk);
 
   // ### Index File Manipulation
-  //
+
-  // The [index file API][gi] allows you to read, traverse, update and write the Git index file
+  // The [index file API][gi] allows you to read, traverse, update and write
-  // (sometimes thought of as the staging area).
+  // the Git index file (sometimes thought of as the staging area).
   //
   // [gi]: http://libgit2.github.com/libgit2/#HEAD/group/index
 
@@ -359,15 +416,18 @@ int main (int argc, char** argv)
   git_index *index;
   unsigned int i, ecount;
 
-  // You can either open the index from the standard location in an open repository, as we're doing
+  // You can either open the index from the standard location in an open
-  // here, or you can open and manipulate any index file with `git_index_open_bare()`. The index
+  // repository, as we're doing here, or you can open and manipulate any
-  // for the repository will be located and loaded from disk.
+  // index file with `git_index_open_bare()`. The index for the repository
+  // will be located and loaded from disk.
   git_repository_index(&index, repo);
 
-  // For each entry in the index, you can get a bunch of information including the SHA (oid), path
+  // For each entry in the index, you can get a bunch of information
-  // and mode which map to the tree objects that are written out.  It also has filesystem properties
+  // including the SHA (oid), path and mode which map to the tree objects
-  // to help determine what to inspect for changes (ctime, mtime, dev, ino, uid, gid, file_size and flags)
+  // that are written out.  It also has filesystem properties to help
-  // All these properties are exported publicly in the `git_index_entry` struct
+  // determine what to inspect for changes (ctime, mtime, dev, ino, uid,
+  // gid, file_size and flags) All these properties are exported publicly in
+  // the `git_index_entry` struct
   ecount = git_index_entrycount(index);
   for (i = 0; i < ecount; ++i) {
     const git_index_entry *e = git_index_get_byindex(index, i);
@@ -380,24 +440,25 @@ int main (int argc, char** argv)
   git_index_free(index);
 
   // ### References
-  //
+
-  // The [reference API][ref] allows you to list, resolve, create and update references such as
+  // The [reference API][ref] allows you to list, resolve, create and update
-  // branches, tags and remote references (everything in the .git/refs directory).
+  // references such as branches, tags and remote references (everything in
+  // the .git/refs directory).
   //
   // [ref]: http://libgit2.github.com/libgit2/#HEAD/group/reference
 
   printf("\n*Reference Listing*\n");
 
-  // Here we will implement something like `git for-each-ref` simply listing out all available
+  // Here we will implement something like `git for-each-ref` simply listing
-  // references and the object SHA they resolve to.
+  // out all available references and the object SHA they resolve to.
   git_strarray ref_list;
   git_reference_list(&ref_list, repo, GIT_REF_LISTALL);
 
   const char *refname;
   git_reference *ref;
 
-  // Now that we have the list of reference names, we can lookup each ref one at a time and
+  // Now that we have the list of reference names, we can lookup each ref
-  // resolve them to the SHA, then print both values out.
+  // one at a time and resolve them to the SHA, then print both values out.
   for (i = 0; i < ref_list.count; ++i) {
     refname = ref_list.strings[i];
     git_reference_lookup(&ref, repo, refname);
@@ -420,9 +481,9 @@ int main (int argc, char** argv)
   git_strarray_free(&ref_list);
 
   // ### Config Files
-  //
+
-  // The [config API][config] allows you to list and updatee config values in
+  // The [config API][config] allows you to list and updatee config values
-  // any of the accessible config file locations (system, global, local).
+  // in any of the accessible config file locations (system, global, local).
   //
   // [config]: http://libgit2.github.com/libgit2/#HEAD/group/config