Fixed some bugs with newline skipping. Improved error handling when a tag is

not closed properly and another tag follows it on the same line. Added support
for -first and -last special variables. Fixed problem with resolving outermost
component of a compound key in parent contexts.

src/main/java/com/samskivert/mustache/Mustache.java

@@ -94,6 +94,7 @@ public class Mustache
                 // if we just parsed an open section or close section task, we'll skip the first
                 // newline character following it, if desired; TODO: handle CR, sigh
                 if (skipNewline) {
+                    skipNewline = false;
                     continue;
                 }
             } else {
@@ -133,6 +134,7 @@ public class Mustache
                         if (text.charAt(0) == '=') {
                             // TODO: change delimiters
                         } else {
+                            sanityCheckTag(text, line, start1, start2);
                             accum = accum.addTagSegment(text, line);
                             skipNewline = accum.skipNewline();
                         }
@@ -150,6 +152,7 @@ public class Mustache
                     if (text.charAt(0) == '=') {
                         // TODO: change delimiters
                     } else {
+                        sanityCheckTag(text, line, start1, start2);
                         accum = accum.addTagSegment(text, line);
                         skipNewline = accum.skipNewline();
                     }
@@ -187,6 +190,19 @@ public class Mustache
 
     private Mustache () {} // no instantiateski
 
+    protected static void sanityCheckTag (StringBuilder accum, int line, char start1, char start2)
+    {
+        for (int ii = 0, ll = accum.length(); ii < ll; ii++) {
+            if (accum.charAt(ii) == start1) {
+                if (start2 == -1 || (ii < ll-1 && accum.charAt(ii+1) == start2)) {
+                    throw new MustacheException(
+                        "Tag contains start tag delimiter, probably missing close delimiter " +
+                        "[line=" + line + ", tag=" + accum + "]");
+                }
+            }
+        }
+    }
+
     protected static String escapeHTML (String text)
     {
         for (int ii = 0; ii < ATTR_ESCAPES.length; ii++) {
@@ -234,7 +250,7 @@ public class Mustache
                     }
                     @Override public Template.Segment[] finish () {
                         throw new MustacheException("Section missing close tag " +
-                                                    "[line=" + line + ", name=" + tag1 + "]");
+                                                    "[line=" + line + ", tag=" + tag1 + "]");
                     }
                     @Override protected Accumulator addCloseSectionSegment (String itag, int line) {
                         requireSameName(tag1, itag, line);
@@ -252,7 +268,7 @@ public class Mustache
                     }
                     @Override public Template.Segment[] finish () {
                         throw new MustacheException("Inverted section missing close tag " +
-                                                    "[line=" + line + ", name=" + tag1 + "]");
+                                                    "[line=" + line + ", tag=" + tag1 + "]");
                     }
                     @Override protected Accumulator addCloseSectionSegment (String itag, int line) {
                         requireSameName(tag1, itag, line);
@@ -287,13 +303,13 @@ public class Mustache
 
         protected Accumulator addCloseSectionSegment (String tag, int line) {
             throw new MustacheException("Section close tag with no open tag " +
-                                        "[line=" + line + ", name=" + tag + "]");
+                                        "[line=" + line + ", tag=" + tag + "]");
         }
 
         protected static void requireNoNewlines (String tag, int line) {
             if (tag.indexOf("\n") != -1 || tag.indexOf("\r") != -1) {
                 throw new MustacheException("Invalid tag name: contains newlne " +
-                                            "[line=" + line + ", name=" + tag + "]");
+                                            "[line=" + line + ", tag=" + tag + "]");
             }
         }
 
@@ -324,7 +340,7 @@ public class Mustache
     /** A helper class for named segments. */
     protected static abstract class NamedSegment extends Template.Segment {
         protected NamedSegment (String name) {
-            _name = name;
+            _name = name.intern();
         }
         protected final String _name;
     }
@@ -371,9 +387,12 @@ public class Mustache
                 return; // TODO: configurable behavior on missing values
             }
             if (value instanceof Iterable<?>) {
-                Iterable<?> iable = (Iterable<?>)value;
+                Template.Mode mode = null;
-                for (Object elem : iable) {
+                for (Iterator<?> iter = ((Iterable<?>)value).iterator(); iter.hasNext(); ) {
-                    executeSegs(tmpl, ctx.nest(elem), out);
+                    Object elem = iter.next();
+                    mode = (mode == null) ? Template.Mode.FIRST :
+                        (iter.hasNext() ? Template.Mode.OTHER : Template.Mode.LAST);
+                    executeSegs(tmpl, ctx.nest(elem, mode), out);
                 }
             } else if (value instanceof Boolean) {
                 if ((Boolean)value) {
@@ -381,15 +400,20 @@ public class Mustache
                 }
             } else if (value.getClass().isArray()) {
                 for (int ii = 0, ll = Array.getLength(value); ii < ll; ii++) {
-                    executeSegs(tmpl, ctx.nest(Array.get(value, ii)), out);
+                    Template.Mode mode = (ii == 0) ? Template.Mode.FIRST :
+                        ((ii == ll-1) ? Template.Mode.LAST : Template.Mode.OTHER);
+                    executeSegs(tmpl, ctx.nest(Array.get(value, ii), mode), out);
                 }
             } else if (value instanceof Iterator<?>) {
-                Iterator<?> iter = (Iterator<?>)value;
+                Template.Mode mode = null;
-                while (iter.hasNext()) {
+                for (Iterator<?> iter = (Iterator<?>)value; iter.hasNext(); ) {
-                    executeSegs(tmpl, ctx.nest(iter.next()), out);
+                    Object elem = iter.next();
+                    mode = (mode == null) ? Template.Mode.FIRST :
+                        (iter.hasNext() ? Template.Mode.OTHER : Template.Mode.LAST);
+                    executeSegs(tmpl, ctx.nest(elem, mode), out);
                 }
             } else {
-                executeSegs(tmpl, ctx.nest(value), out);
+                executeSegs(tmpl, ctx.nest(value, Template.Mode.OTHER), out);
             }
         }
     }

src/main/java/com/samskivert/mustache/Template.java

@@ -42,7 +42,7 @@ public class Template
      */
     public void execute (Object context, Writer out) throws MustacheException
     {
-        Context ctx = new Context(context, null);
+        Context ctx = new Context(context, null, Mode.OTHER);
         for (Segment seg : _segs) {
             seg.execute(this, ctx, out);
         }
@@ -67,9 +67,41 @@ public class Template
     /**
      * Called by executing segments to obtain the value of the specified variable in the supplied
      * context.
+     *
+     * @param ctx the context in which to look up the variable.
+     * @param name the name of the variable to be resolved, which must be an interned string.
      */
     protected Object getValue (Context ctx, String name)
     {
+        // if we're dealing with a compound key, resolve each component and use the result to
+        // resolve the subsequent component and so forth
+        if (name.indexOf(".") != -1) {
+            String[] comps = name.split("\\.");
+            // we want to allow the first component of a compound key to be located in a parent
+            // context, but once we're selecting sub-components, they must only be resolved in the
+            // object that represents that component
+            Object data = getValue(ctx, comps[0].intern());
+            for (int ii = 1; ii < comps.length; ii++) {
+                // generate more helpful error message
+                if (data == null) {
+                    throw new NullPointerException(
+                        "Null context for compound variable '" + name + "'. " +
+                        "The component previous to '" + comps[ii] + "' resolved to null.");
+                }
+                // once we step into a composite key, we drop the ability to query our parent
+                // contexts; that would be weird and confusing
+                data = getValueIn(data, comps[ii].intern());
+            }
+            return data;
+        }
+
+        // handle our special variables
+        if (name == FIRST_NAME) {
+            return ctx.mode == Mode.FIRST;
+        } else if (name == LAST_NAME) {
+            return ctx.mode == Mode.LAST;
+        }
+
         while (ctx != null) {
             Object value = getValueIn(ctx.data, name);
             if (value != null) {
@@ -87,17 +119,6 @@ public class Template
             throw new NullPointerException("Null context for variable '" + name + "'");
         }
 
-        // if we're dealing with a composite key, resolve each component and use the result to
-        // resolve the subsequent component and so forth
-        if (name.indexOf(".") != -1) {
-            for (String comp : name.split("\\.")) {
-                // once we step into a composite key, we drop the ability to query our parent
-                // contexts; that would be weird and confusing
-                data = getValueIn(data, comp);
-            }
-            return data;
-        }
-
         Key key = new Key(data.getClass(), name);
         VariableFetcher fetcher = _fcache.get(key);
         if (fetcher != null) {
@@ -215,18 +236,22 @@ public class Template
         return null;
     }
 
+    protected static enum Mode { FIRST, OTHER, LAST };
+
     protected static class Context
     {
         public final Object data;
         public final Context parent;
+        public final Mode mode;
 
-        public Context (Object data, Context parent) {
+        public Context (Object data, Context parent, Mode mode) {
             this.data = data;
             this.parent = parent;
+            this.mode = mode;
         }
 
-        public Context nest (Object data) {
+        public Context nest (Object data, Mode mode) {
-            return new Context(data, this);
+            return new Context(data, this, mode);
         }
     }
 
@@ -252,7 +277,7 @@ public class Template
 
         public Key (Class<?> cclass, String name) {
             this.cclass = cclass;
-            this.name = name.intern();
+            this.name = name;
         }
 
         @Override public int hashCode () {
@@ -282,4 +307,6 @@ public class Template
     };
 
     protected static final String THIS_NAME = "this".intern();
+    protected static final String FIRST_NAME = "-first".intern();
+    protected static final String LAST_NAME = "-last".intern();
 }

src/test/java/com/samskivert/mustache/MustacheTest.java

@@ -178,6 +178,16 @@ public class MustacheTest
                      "things", Arrays.asList(context("name", "bar"), context("name", "baz"))));
     }
 
+    @Test public void testFirst () {
+        test("foo|bar|baz", "{{#things}}{{^-first}}|{{/-first}}{{this}}{{/things}}",
+             context("things", Arrays.asList("foo", "bar", "baz")));
+    }
+
+    @Test public void testLast () {
+        test("foo|bar|baz", "{{#things}}{{this}}{{^-last}}|{{/-last}}{{/things}}",
+             context("things", Arrays.asList("foo", "bar", "baz")));
+    }
+
     protected void test (String expected, String template, Object ctx)
     {
         assertEquals(expected, Mustache.compiler().compile(template).execute(ctx));