imp(Help Wrapping): clap now ignores hard newlines in help messages a…

…nd properly re-aligns text, but still wraps if the term width is too small

Prior to this commit, clap would mangle help messages with hard newlines
(see #617). After this commit, clap will ignore hard newlines and treat
them like an inserted newline, properly wrapping and aligning text and
then restarting it's count until the next newline should be inserted.

This commit also removes the need for using `{n}` to insert a newline in
help text, now the traditional `\n` can be used. For backwards
compatibility, the `{n}` still works.

Closes #617

src/app/help.rs

@@ -365,6 +365,11 @@ impl<'a> Help<'a> {
                 }
                 lw
             };
+            help = if help.contains("{n}") {
+                help.replace("{n}", "\n")
+            } else {
+                help
+            };
             wrap_help(&mut help, longest_w, width);
         } else {
             sdebugln!("No");
@@ -445,6 +450,11 @@ impl<'a> Help<'a> {
                 }
                 lw
             };
+            help = if help.contains("{n}") {
+                help.replace("{n}", "\n")
+            } else {
+                help
+            };
             wrap_help(&mut help, longest_w, avail_chars);
         } else {
             sdebugln!("No");
@@ -458,11 +468,11 @@ impl<'a> Help<'a> {
             help.push_str(&*spec_vals);
             &*help
         };
-        if help.contains("{n}") {
-            if let Some(part) = help.split("{n}").next() {
+        if help.contains("\n") {
+            if let Some(part) = help.split("\n").next() {
                 try!(write!(self.writer, "{}", part));
             }
-            for part in help.split("{n}").skip(1) {
+            for part in help.split("\n").skip(1) {
                 try!(write!(self.writer, "\n"));
                 if nlh || force_next_line {
                     try!(write!(self.writer, "{}{}{}", TAB, TAB, TAB));
@@ -920,27 +930,37 @@ fn wrap_help(help: &mut String, longest_w: usize, avail_chars: usize) {
         sdebugln!("Yes");
         let mut prev_space = 0;
         let mut j = 0;
-        let mut i = 0;
+        // let mut i = 0;
         for (idx, g) in (&*help.clone()).grapheme_indices(true) {
             debugln!("iter;idx={},g={}", idx, g);
-            if g != " " {
-                continue;
-            }
-            if str_width(&help[j..idx + (2 * i)]) < avail_chars {
-                debugln!("Still enough space...");
+            if g == "\n" {
+                debugln!("Newline found...");
+                debugln!("Still space...{:?}", str_width(&help[j..idx]) < avail_chars);
+                if str_width(&help[j..idx]) < avail_chars {
+                    // i += 1;
+                    j = idx; // + i;
+                    continue;
+                }
+            } else if g != " " {
+                if idx != help.len() - 1 || str_width(&help[j..idx]) < avail_chars {
+                    continue;
+                }
+                debugln!("Reached the end of the line and we're over...");
+            } else if str_width(&help[j..idx]) < avail_chars { //(2 * i)]) < avail_chars {
+                debugln!("Space found with room...");
                 prev_space = idx;
                 continue;
             }
             debugln!("Adding Newline...");
-            j = prev_space + (2 * i);
-            debugln!("i={},prev_space={},j={}", i, prev_space, j);
+            j = prev_space; // + i;//(2 * i);
+            debugln!("prev_space={},j={}", prev_space, j);
             debugln!("removing: {}", j);
             debugln!("char at {}: {}", j, &help[j..j]);
             help.remove(j);
-            help.insert(j, '{');
-            help.insert(j + 1, 'n');
-            help.insert(j + 2, '}');
-            i += 1;
+            help.insert(j, '\n');
+            // help.insert(j + 1, 'n');
+            // help.insert(j + 2, '}');
+            // i += 1;
         }
     } else {
         sdebugln!("No");