the parser in the C runtime can now detect incomplete sentences just like the parser in the Haskell runtime. This is also reflected in all bindings.

src/compiler/GF/Command/Commands2.hs

@@ -636,10 +636,12 @@ pgfCommands = Map.fromList [
        cncs = optConcs env opts
        parsed rs = Piped (Exprs ts,unlines msgs)
           where
-            ts = [hsExpr t|Right ts<-rs,(t,p)<-takeOptNum opts ts]
-            msgs = concatMap (either err ok) rs
-            err msg = ["Parse failed: "++msg]
-            ok = map (PGF2.showExpr [] . fst).takeOptNum opts
+            ts = [hsExpr t|ParseOk ts<-rs,(t,p)<-takeOptNum opts ts]
+            msgs = concatMap mkMsg rs
+
+            mkMsg (ParseOk ts) = (map (PGF2.showExpr [] . fst).takeOptNum opts) ts
+            mkMsg (ParseFailed _ tok) = ["Parse failed: "++tok]
+            mkMsg (ParseIncomplete)   = ["The sentence is incomplete"]
 
    optLins env opts ts = case opts of
      _ | isOpt "groups" opts ->

src/runtime/c/pgf/parser.c

@@ -2139,30 +2139,37 @@ pgf_parse_result_enum_next(GuEnum* self, void* to, GuPool* pool)
 	*(PgfExprProb**)to = pgf_parse_result_next(ps);
 }
 
-static GuString
-pgf_parsing_last_token(PgfParsing* ps, GuPool* pool)
+static PgfParseError*
+pgf_parsing_new_exception(PgfParsing* ps, GuPool* pool)
 {
-	if (ps->before == NULL)
-		return "";
+	const uint8_t* p   = (uint8_t*) ps->sentence;
+	const uint8_t* end = p + (ps->before ? ps->before->end_offset : 0);
 
-	const uint8_t* start = (uint8_t*) ps->sentence;
-	const uint8_t* end   = (uint8_t*) ps->sentence + ps->before->end_offset;
+	PgfParseError* err = gu_new(PgfParseError, pool);
+	err->incomplete= (*end == 0);
+	err->offset    = 0;
+	err->token_ptr = (char*) p;
 
-	const uint8_t* p = start;
 	while (p < end) {
 		if (gu_ucs_is_space(gu_utf8_decode(&p))) {
-			start = p;
+			err->token_ptr = (char*) p;
 		}
+		err->offset++;
+	}
+
+	if (err->incomplete) {
+		err->token_ptr = NULL;
+		err->token_len = 0;
+		return err;
 	}
 
 	while (*p && !gu_ucs_is_space(gu_utf8_decode(&p))) {
 		end = p;
 	}
 
-	char* tok = gu_malloc(pool, end-start+1);
-	memcpy(tok, start, (end-start));
-	tok[end-start] = 0;
-	return tok;
+	err->token_len = ((char*)end)-err->token_ptr;
+
+	return err;
 }
 
 PGF_API GuEnum*
@@ -2204,7 +2211,7 @@ pgf_parse_with_heuristics(PgfConcr* concr, PgfType* typ, GuString sentence,
 	while (gu_buf_length(ps->expr_queue) == 0) {
 		if (!pgf_parsing_proceed(ps)) {
 			GuExnData* exn = gu_raise(err, PgfParseError);
-			exn->data = (void*) pgf_parsing_last_token(ps, exn->pool);
+			exn->data = (void*) pgf_parsing_new_exception(ps, exn->pool);
 			return NULL;
 		}
 
@@ -2249,7 +2256,7 @@ pgf_parse_with_oracle(PgfConcr* concr, PgfType* typ,
 	while (gu_buf_length(ps->expr_queue) == 0) {
 		if (!pgf_parsing_proceed(ps)) {
 			GuExnData* exn = gu_raise(err, PgfParseError);
-			exn->data = (void*) pgf_parsing_last_token(ps, exn->pool);
+			exn->data = (void*) pgf_parsing_new_exception(ps, exn->pool);
 			return NULL;
 		}
 
@@ -2312,7 +2319,7 @@ pgf_complete(PgfConcr* concr, PgfType* type, GuString sentence,
 	while (ps->before->end_offset < len) {
 		if (!pgf_parsing_proceed(ps)) {
 			GuExnData* exn = gu_raise(err, PgfParseError);
-			exn->data = (void*) pgf_parsing_last_token(ps, exn->pool);
+			exn->data = (void*) pgf_parsing_new_exception(ps, exn->pool);
 			return NULL;
 		}
 

src/runtime/c/pgf/pgf.h

@@ -122,6 +122,13 @@ PGF_API_DECL PgfExprEnum*
 pgf_generate_all(PgfPGF* pgf, PgfType* ty,
                  GuExn* err, GuPool* pool, GuPool* out_pool);
 
+typedef struct {
+	int incomplete;   // equal to !=0 if the sentence is incomplete, 0 otherwise
+	size_t offset;
+	const char*  token_ptr;
+	size_t       token_len;
+} PgfParseError;
+
 PGF_API_DECL PgfExprEnum*
 pgf_parse(PgfConcr* concr, PgfType* typ, GuString sentence,
           GuExn* err, GuPool* pool, GuPool* out_pool);

src/runtime/haskell-bind/PGF2.hsc

@@ -63,7 +63,7 @@ module PGF2 (-- * PGF
 
              alignWords,
              -- ** Parsing
-             parse, parseWithHeuristics,
+             ParseOutput(..), parse, parseWithHeuristics,
              -- ** Sentence Lookup
              lookupSentence,
              -- ** Generation
@@ -480,7 +480,15 @@ getAnalysis ref self c_lemma c_anal prob exn = do
   anal  <- peekUtf8CString c_anal
   writeIORef ref ((lemma, anal, prob):ans)
 
-parse :: Concr -> Type -> String -> Either String [(Expr,Float)]
+-- | This data type encodes the different outcomes which you could get from the parser.
+data ParseOutput
+  = ParseFailed Int String         -- ^ The integer is the position in number of unicode characters where the parser failed.
+                                   -- The string is the token where the parser have failed.
+  | ParseOk [(Expr,Float)]         -- ^ If the parsing and the type checking are successful we get a list of abstract syntax trees.
+                                   -- The list should be non-empty.
+  | ParseIncomplete                -- ^ The sentence is not complete.
+
+parse :: Concr -> Type -> String -> ParseOutput
 parse lang ty sent = parseWithHeuristics lang ty sent (-1.0) []
 
 parseWithHeuristics :: Concr      -- ^ the language with which we parse
@@ -497,7 +505,7 @@ parseWithHeuristics :: Concr      -- ^ the language with which we parse
                                   -- the input sentence; the current offset in the sentence.
                                   -- If a literal has been recognized then the output should
                                   -- be Just (expr,probability,end_offset)
-                    -> Either String [(Expr,Float)]
+                    -> ParseOutput
 parseWithHeuristics lang (Type ctype _) sent heuristic callbacks =
   unsafePerformIO $
     do exprPl  <- gu_new_pool
@@ -510,11 +518,19 @@ parseWithHeuristics lang (Type ctype _) sent heuristic callbacks =
        if failed
          then do is_parse_error <- gu_exn_caught exn gu_exn_type_PgfParseError
                  if is_parse_error
-                   then do c_tok <- (#peek GuExn, data.data) exn
-                           tok <- peekUtf8CString c_tok
-                           gu_pool_free parsePl
-                           gu_pool_free exprPl
-                           return (Left tok)
+                   then do c_err <- (#peek GuExn, data.data) exn
+                           c_incomplete <- (#peek PgfParseError, incomplete) c_err
+                           if (c_incomplete :: CInt) == 0
+                             then do c_offset <- (#peek PgfParseError, offset) c_err
+                                     token_ptr <- (#peek PgfParseError, token_ptr) c_err
+                                     token_len <- (#peek PgfParseError, token_len) c_err
+                                     tok <- peekUtf8CStringLen token_ptr token_len
+                                     gu_pool_free parsePl
+                                     gu_pool_free exprPl
+                                     return (ParseFailed (fromIntegral (c_offset :: CInt)) tok)
+                             else do gu_pool_free parsePl
+                                     gu_pool_free exprPl
+                                     return ParseIncomplete
                    else do is_exn <- gu_exn_caught exn gu_exn_type_PgfExn
                            if is_exn
                              then do c_msg <- (#peek GuExn, data.data) exn
@@ -528,7 +544,7 @@ parseWithHeuristics lang (Type ctype _) sent heuristic callbacks =
          else do parseFPl <- newForeignPtr gu_pool_finalizer parsePl
                  exprFPl  <- newForeignPtr gu_pool_finalizer exprPl
                  exprs    <- fromPgfExprEnum enum parseFPl (touchConcr lang >> touchForeignPtr exprFPl)
-                 return (Right exprs)
+                 return (ParseOk exprs)
 
 mkCallbacksMap :: Ptr PgfConcr -> [(String, Int -> Int -> Maybe (Expr,Float,Int))] -> Ptr GuPool -> IO (Ptr PgfCallbacksMap)
 mkCallbacksMap concr callbacks pool = do
@@ -595,7 +611,7 @@ parseWithOracle :: Concr      -- ^ the language with which we parse
                 -> Cat        -- ^ the start category
                 -> String     -- ^ the input sentence
                 -> Oracle
-                -> Either String [(Expr,Float)]
+                -> ParseOutput
 parseWithOracle lang cat sent (predict,complete,literal) =
   unsafePerformIO $
     do parsePl <- gu_new_pool
@@ -612,11 +628,19 @@ parseWithOracle lang cat sent (predict,complete,literal) =
        if failed
          then do is_parse_error <- gu_exn_caught exn gu_exn_type_PgfParseError
                  if is_parse_error
-                   then do c_tok <- (#peek GuExn, data.data) exn
-                           tok <- peekUtf8CString c_tok
-                           gu_pool_free parsePl
-                           gu_pool_free exprPl
-                           return (Left tok)
+                   then do c_err <- (#peek GuExn, data.data) exn
+                           c_incomplete <- (#peek PgfParseError, incomplete) c_err
+                           if (c_incomplete :: CInt) == 0
+                             then do c_offset <- (#peek PgfParseError, offset) c_err
+                                     token_ptr <- (#peek PgfParseError, token_ptr) c_err
+                                     token_len <- (#peek PgfParseError, token_len) c_err
+                                     tok <- peekUtf8CStringLen token_ptr token_len
+                                     gu_pool_free parsePl
+                                     gu_pool_free exprPl
+                                     return (ParseFailed (fromIntegral (c_offset :: CInt)) tok)
+                             else do gu_pool_free parsePl
+                                     gu_pool_free exprPl
+                                     return ParseIncomplete
                    else do is_exn <- gu_exn_caught exn gu_exn_type_PgfExn
                            if is_exn
                              then do c_msg <- (#peek GuExn, data.data) exn
@@ -630,7 +654,7 @@ parseWithOracle lang cat sent (predict,complete,literal) =
          else do parseFPl <- newForeignPtr gu_pool_finalizer parsePl
                  exprFPl  <- newForeignPtr gu_pool_finalizer exprPl
                  exprs    <- fromPgfExprEnum enum parseFPl (touchConcr lang >> touchForeignPtr exprFPl)
-                 return (Right exprs)
+                 return (ParseOk exprs)
   where
     oracleWrapper oracle catPtr lblPtr offset = do
       cat <- peekUtf8CString catPtr

src/runtime/haskell-bind/PGF2/FFI.hs

@@ -2,7 +2,7 @@
 
 module PGF2.FFI where
 
-import Foreign ( alloca, poke )
+import Foreign ( alloca, peek, poke )
 import Foreign.C
 import Foreign.Ptr
 import Foreign.ForeignPtr
@@ -116,6 +116,19 @@ peekUtf8CString ptr =
         else do cs <- decode pptr
                 return (((toEnum . fromEnum) x) : cs)
 
+peekUtf8CStringLen :: CString -> CInt -> IO String
+peekUtf8CStringLen ptr len =
+  alloca $ \pptr ->
+    poke pptr ptr >> decode pptr (ptr `plusPtr` fromIntegral len)
+  where
+    decode pptr end = do
+      ptr <- peek pptr
+      if ptr >= end
+        then return []
+        else do x <- gu_utf8_decode pptr
+                cs <- decode pptr end
+                return (((toEnum . fromEnum) x) : cs)
+
 newUtf8CString :: String -> Ptr GuPool -> IO CString
 newUtf8CString s pool = do
   -- An UTF8 character takes up to 6 bytes. We allocate enough

src/runtime/haskell-bind/examples/pgf-shell.hs

@@ -37,18 +37,18 @@ execute cmd =
     P lang s    -> do pgf <- gets fst
                       c <- getConcr' pgf lang
                       case parse c (startCat pgf) s of
-                        Left tok -> do put (pgf,[])
-                                       putln ("Parse error: "++tok)
-                        Right ts -> do put (pgf,map show ts)
-                                       pop
+                        ParseFailed _ tok -> do put (pgf,[])
+                                                putln ("Parse error: "++tok)
+                        ParseOk ts        -> do put (pgf,map show ts)
+                                                pop
     T from to s -> do pgf <- gets fst
                       cfrom <- getConcr' pgf from
                       cto   <- getConcr' pgf to
                       case parse cfrom (startCat pgf) s of
-                        Left tok -> do put (pgf,[])
-                                       putln ("Parse error: "++tok)
-                        Right ts -> do put (pgf,map (linearize cto.fst) ts)
-                                       pop
+                        ParseFailed _ tok -> do put (pgf,[])
+                                                putln ("Parse error: "++tok)
+                        ParseOk ts        -> do put (pgf,map (linearize cto.fst) ts)
+                                                pop
     I path -> do pgf <- liftIO (readPGF path)
                  putln . unwords . M.keys $ languages pgf
                  put (pgf,[])

src/runtime/java/jni_utils.c

@@ -34,10 +34,8 @@ gu2j_string(JNIEnv *env, GuString s) {
 }
 
 JPGF_INTERNAL jstring
-gu2j_string_buf(JNIEnv *env, GuStringBuf* sbuf) {
-	const char* s    = gu_string_buf_data(sbuf);
+gu2j_string_len(JNIEnv *env, const char* s, size_t len) {
 	const char* utf8 = s;
-	size_t len = gu_string_buf_length(sbuf);
 
 	jchar* utf16 = alloca(len*sizeof(jchar));
 	jchar* dst   = utf16;
@@ -56,6 +54,11 @@ gu2j_string_buf(JNIEnv *env, GuStringBuf* sbuf) {
 	return (*env)->NewString(env, utf16, dst-utf16);
 }
 
+JPGF_INTERNAL jstring
+gu2j_string_buf(JNIEnv *env, GuStringBuf* sbuf) {
+	return gu2j_string_len(env, gu_string_buf_data(sbuf), gu_string_buf_length(sbuf));
+}
+
 JPGF_INTERNAL GuString
 j2gu_string(JNIEnv *env, jstring s, GuPool* pool) {
 	GuString str = (*env)->GetStringUTFChars(env, s, 0);

src/runtime/java/jni_utils.h

@@ -20,6 +20,9 @@
 JPGF_INTERNAL_DECL jstring
 gu2j_string(JNIEnv *env, GuString s);
 
+JPGF_INTERNAL_DECL jstring
+gu2j_string_len(JNIEnv *env, const char* s, size_t len);
+
 JPGF_INTERNAL_DECL jstring
 gu2j_string_buf(JNIEnv *env, GuStringBuf* sbuf);
 

src/runtime/java/jpgf.c

@@ -591,6 +591,30 @@ JNIEXPORT void JNICALL Java_org_grammaticalframework_pgf_Parser_addLiteralCallba
                                   j2gu_string(env, jcat, pool), &callback->callback);
 }
 
+static void
+throw_parse_error(JNIEnv *env, PgfParseError* err)
+{
+	jstring jtoken;
+	if (err->incomplete)
+		jtoken = NULL;
+	else {
+		jtoken = gu2j_string_len(env, err->token_ptr, err->token_len);
+		if (!jtoken)
+			return;
+	}
+
+	jclass exception_class = (*env)->FindClass(env, "org/grammaticalframework/pgf/ParseError");
+	if (!exception_class)
+		return;
+	jmethodID constrId = (*env)->GetMethodID(env, exception_class, "<init>", "(Ljava/lang/String;IZ)V");
+	if (!constrId)
+		return;
+	jobject exception = (*env)->NewObject(env, exception_class, constrId, jtoken, err->offset, err->incomplete);
+	if (!exception)
+		return;
+	(*env)->Throw(env, exception);
+}
+
 JNIEXPORT jobject JNICALL 
 Java_org_grammaticalframework_pgf_Parser_parseWithHeuristics
   (JNIEnv* env, jclass clazz, jobject jconcr, jstring jstartCat, jstring js, jdouble heuristics, jlong callbacksRef, jobject jpool)
@@ -615,8 +639,7 @@ Java_org_grammaticalframework_pgf_Parser_parseWithHeuristics
 			GuString msg = (GuString) gu_exn_caught_data(parse_err);
 			throw_string_exception(env, "org/grammaticalframework/pgf/PGFError", msg);
 		} else if (gu_exn_caught(parse_err, PgfParseError)) {
-			GuString tok = (GuString) gu_exn_caught_data(parse_err);
-			throw_string_exception(env, "org/grammaticalframework/pgf/ParseError", tok);
+			throw_parse_error(env, (PgfParseError*) gu_exn_caught_data(parse_err));
 		}
 
 		gu_pool_free(out_pool);
@@ -656,8 +679,7 @@ Java_org_grammaticalframework_pgf_Completer_complete(JNIEnv* env, jclass clazz,
 			GuString msg = (GuString) gu_exn_caught_data(parse_err);
 			throw_string_exception(env, "org/grammaticalframework/pgf/PGFError", msg);
 		} else if (gu_exn_caught(parse_err, PgfParseError)) {
-			GuString tok = (GuString) gu_exn_caught_data(parse_err);
-			throw_string_exception(env, "org/grammaticalframework/pgf/ParseError", tok);
+			throw_parse_error(env, (PgfParseError*) gu_exn_caught_data(parse_err));
 		}
 
 		gu_pool_free(pool);

src/runtime/java/org/grammaticalframework/pgf/ParseError.java

@@ -4,11 +4,26 @@ package org.grammaticalframework.pgf;
 public class ParseError extends Exception {
 	private static final long serialVersionUID = -6086991674218306569L;
 
-	public ParseError(String token) {
-		super(token);
+	private String  token;
+	private int     offset;
+	private boolean incomplete;
+
+	public ParseError(String token, int offset, boolean incomplete) {
+		super(incomplete ? "The sentence is incomplete" : "Unexpected token: \""+token+"\"");
+		this.token      = token;
+		this.offset     = offset;
+		this.incomplete = incomplete;
+	}
+
+	public String getToken() {
+		return token;
+	}
+
+	public int getOffset() {
+		return offset;
 	}
 	
-	public String getToken() {
-		return getMessage();
+	public boolean isIncomplete() {
+		return incomplete;
 	}
 }

src/runtime/python/pypgf.c

@@ -1545,13 +1545,28 @@ Concr_parse(ConcrObject* self, PyObject *args, PyObject *keywds)
 			GuString msg = (GuString) gu_exn_caught_data(parse_err);
 			PyErr_SetString(PGFError, msg);
 		} else if (gu_exn_caught(parse_err, PgfParseError)) {
-			GuString tok = (GuString) gu_exn_caught_data(parse_err);
-			PyObject* py_tok = PyString_FromString(tok);
-			PyObject_SetAttrString(ParseError, "token", py_tok);
-			PyErr_Format(ParseError, "Unexpected token: \"%s\"", tok);
-			Py_DECREF(py_tok);
+			PgfParseError* err = (PgfParseError*) gu_exn_caught_data(parse_err);
+			PyObject* py_offset = PyInt_FromLong(err->offset);
+			if (err->incomplete) {
+	            PyObject_SetAttrString(ParseError, "incomplete",  Py_True);
+	            PyObject_SetAttrString(ParseError, "offset",      py_offset);
+				PyErr_Format(ParseError, "The sentence is incomplete");
+			} else {
+				PyObject* py_tok    = PyString_FromStringAndSize(err->token_ptr,
+	                                                             err->token_len);
+	            PyObject_SetAttrString(ParseError, "incomplete",  Py_False);
+				PyObject_SetAttrString(ParseError, "offset",      py_offset);
+				PyObject_SetAttrString(ParseError, "token",       py_tok);
+#if PY_MAJOR_VERSION >= 3
+				PyErr_Format(ParseError, "Unexpected token: \"%U\"", py_tok);
+#else
+				PyErr_Format(ParseError, "Unexpected token: \"%s\"", PyString_AsString(py_tok));
+#endif
+				Py_DECREF(py_tok);
+			}
+			Py_DECREF(py_offset);
 		}
-		
+
 		Py_DECREF(pyres);
 		pyres = NULL;
 	}

src/server/PGFService.hs

@@ -191,10 +191,11 @@ cpgfMain qsem command (t,(pgf,pc)) =
 
     -- Without caching parse results:
     parse' start mlimit ((from,concr),input) =
-        return $ maybe id take mlimit . drop start # cparse
+        case C.parseWithHeuristics concr cat input (-1) callbacks of
+          C.ParseOk ts        -> return (Right (maybe id take mlimit (drop start ts)))
+          C.ParseFailed _ tok -> return (Left tok)
+          C.ParseIncomplete   -> return (Left "")
       where
-      --cparse = C.parse concr cat input
-        cparse = C.parseWithHeuristics concr cat input (-1) callbacks
         callbacks = maybe [] cb $ lookup (C.abstractName pgf) C.literalCallbacks
         cb fs = [(cat,f pgf (from,concr) input)|(cat,f)<-fs]
 {-
@@ -277,8 +278,9 @@ cpgfMain qsem command (t,(pgf,pc)) =
                         | isUpper c -> toLower c : cs
                    s                -> s
 
-            parse1 = either (const Nothing) (fmap fst . listToMaybe) .
-                     C.parse concr cat
+            parse1 s = case C.parse concr cat s of
+                         C.ParseOk ((t,_):ts) -> Just t
+                         _                    -> Nothing
             morph w = listToMaybe
                         [t | (f,a,p)<-C.lookupMorpho concr w,
                              t<-maybeToList (C.readExpr f)]