tree schema helpers REFACTOR
merge similar functions from yin and yang parser into one helper function
diff --git a/src/parser_yang.c b/src/parser_yang.c
index 5b24afe..f8735ba 100644
--- a/src/parser_yang.c
+++ b/src/parser_yang.c
@@ -765,197 +765,14 @@
         ++(*data);
     }
 
-#define IF_KW(STR, LEN, STMT) if (!strncmp(*(data), STR, LEN)) {MOVE_INPUT(ctx, data, LEN);*kw=STMT;}
-#define IF_KW_PREFIX(STR, LEN) if (!strncmp(*(data), STR, LEN)) {MOVE_INPUT(ctx, data, LEN);
-#define IF_KW_PREFIX_END }
-
 keyword_start:
     word_start = *data;
-    *kw = YANG_NONE;
+    *kw = match_kw(ctx, data);
 
-    /* read the keyword itself */
-    switch (**data) {
-    case 'a':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("rgument", 7, YANG_ARGUMENT)
-        else IF_KW("ugment", 6, YANG_AUGMENT)
-        else IF_KW("ction", 5, YANG_ACTION)
-        else IF_KW_PREFIX("ny", 2)
-            IF_KW("data", 4, YANG_ANYDATA)
-            else IF_KW("xml", 3, YANG_ANYXML)
-        IF_KW_PREFIX_END
-        break;
-    case 'b':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("ase", 3, YANG_BASE)
-        else IF_KW("elongs-to", 9, YANG_BELONGS_TO)
-        else IF_KW("it", 2, YANG_BIT)
-        break;
-    case 'c':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("ase", 3, YANG_CASE)
-        else IF_KW("hoice", 5, YANG_CHOICE)
-        else IF_KW_PREFIX("on", 2)
-            IF_KW("fig", 3, YANG_CONFIG)
-            else IF_KW_PREFIX("ta", 2)
-                IF_KW("ct", 2, YANG_CONTACT)
-                else IF_KW("iner", 4, YANG_CONTAINER)
-            IF_KW_PREFIX_END
-        IF_KW_PREFIX_END
-        break;
-    case 'd':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW_PREFIX("e", 1)
-            IF_KW("fault", 5, YANG_DEFAULT)
-            else IF_KW("scription", 9, YANG_DESCRIPTION)
-            else IF_KW_PREFIX("viat", 4)
-                IF_KW("e", 1, YANG_DEVIATE)
-                else IF_KW("ion", 3, YANG_DEVIATION)
-            IF_KW_PREFIX_END
-        IF_KW_PREFIX_END
-        break;
-    case 'e':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("num", 3, YANG_ENUM)
-        else IF_KW_PREFIX("rror-", 5)
-            IF_KW("app-tag", 7, YANG_ERROR_APP_TAG)
-            else IF_KW("message", 7, YANG_ERROR_MESSAGE)
-        IF_KW_PREFIX_END
-        else IF_KW("xtension", 8, YANG_EXTENSION)
-        break;
-    case 'f':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("eature", 6, YANG_FEATURE)
-        else IF_KW("raction-digits", 14, YANG_FRACTION_DIGITS)
-        break;
-    case 'g':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("rouping", 7, YANG_GROUPING)
-        break;
-    case 'i':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("dentity", 7, YANG_IDENTITY)
-        else IF_KW("f-feature", 9, YANG_IF_FEATURE)
-        else IF_KW("mport", 5, YANG_IMPORT)
-        else IF_KW_PREFIX("n", 1)
-            IF_KW("clude", 5, YANG_INCLUDE)
-            else IF_KW("put", 3, YANG_INPUT)
-        IF_KW_PREFIX_END
-        break;
-    case 'k':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("ey", 2, YANG_KEY)
-        break;
-    case 'l':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW_PREFIX("e", 1)
-            IF_KW("af-list", 7, YANG_LEAF_LIST)
-            else IF_KW("af", 2, YANG_LEAF)
-            else IF_KW("ngth", 4, YANG_LENGTH)
-        IF_KW_PREFIX_END
-        else IF_KW("ist", 3, YANG_LIST)
-        break;
-    case 'm':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW_PREFIX("a", 1)
-            IF_KW("ndatory", 7, YANG_MANDATORY)
-            else IF_KW("x-elements", 10, YANG_MAX_ELEMENTS)
-        IF_KW_PREFIX_END
-        else IF_KW("in-elements", 11, YANG_MIN_ELEMENTS)
-        else IF_KW("ust", 3, YANG_MUST)
-        else IF_KW_PREFIX("od", 2)
-            IF_KW("ule", 3, YANG_MODULE)
-            else IF_KW("ifier", 5, YANG_MODIFIER)
-        IF_KW_PREFIX_END
-        break;
-    case 'n':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("amespace", 8, YANG_NAMESPACE)
-        else IF_KW("otification", 11, YANG_NOTIFICATION)
-        break;
-    case 'o':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW_PREFIX("r", 1)
-            IF_KW("dered-by", 8, YANG_ORDERED_BY)
-            else IF_KW("ganization", 10, YANG_ORGANIZATION)
-        IF_KW_PREFIX_END
-        else IF_KW("utput", 5, YANG_OUTPUT)
-        break;
-    case 'p':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("ath", 3, YANG_PATH)
-        else IF_KW("attern", 6, YANG_PATTERN)
-        else IF_KW("osition", 7, YANG_POSITION)
-        else IF_KW_PREFIX("re", 2)
-            IF_KW("fix", 3, YANG_PREFIX)
-            else IF_KW("sence", 5, YANG_PRESENCE)
-        IF_KW_PREFIX_END
-        break;
-    case 'r':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("ange", 4, YANG_RANGE)
-        else IF_KW_PREFIX("e", 1)
-            IF_KW_PREFIX("f", 1)
-                IF_KW("erence", 6, YANG_REFERENCE)
-                else IF_KW("ine", 3, YANG_REFINE)
-            IF_KW_PREFIX_END
-            else IF_KW("quire-instance", 14, YANG_REQUIRE_INSTANCE)
-            else IF_KW("vision-date", 11, YANG_REVISION_DATE)
-            else IF_KW("vision", 6, YANG_REVISION)
-        IF_KW_PREFIX_END
-        else IF_KW("pc", 2, YANG_RPC)
-        break;
-    case 's':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("tatus", 5, YANG_STATUS)
-        else IF_KW("ubmodule", 8, YANG_SUBMODULE)
-        break;
-    case 't':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("ypedef", 6, YANG_TYPEDEF)
-        else IF_KW("ype", 3, YANG_TYPE)
-        break;
-    case 'u':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW_PREFIX("ni", 2)
-            IF_KW("que", 3, YANG_UNIQUE)
-            else IF_KW("ts", 2, YANG_UNITS)
-        IF_KW_PREFIX_END
-        else IF_KW("ses", 3, YANG_USES)
-        break;
-    case 'v':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("alue", 4, YANG_VALUE)
-        break;
-    case 'w':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("hen", 3, YANG_WHEN)
-        break;
-    case 'y':
-        MOVE_INPUT(ctx, data, 1);
-        IF_KW("ang-version", 11, YANG_YANG_VERSION)
-        else IF_KW("in-element", 10, YANG_YIN_ELEMENT)
-        break;
-    case ';':
-        MOVE_INPUT(ctx, data, 1);
-        *kw = YANG_SEMICOLON;
+    if (*kw == YANG_SEMICOLON || *kw == YANG_LEFT_BRACE || *kw == YANG_RIGHT_BRACE) {
         goto success;
-    case '{':
-        MOVE_INPUT(ctx, data, 1);
-        *kw = YANG_LEFT_BRACE;
-        goto success;
-    case '}':
-        MOVE_INPUT(ctx, data, 1);
-        *kw = YANG_RIGHT_BRACE;
-        goto success;
-    default:
-        break;
     }
 
-#undef IF_KW
-#undef IF_KW_PREFIX
-#undef IF_KW_PREFIX_END
-
     if (*kw != YANG_NONE) {
         /* make sure we have the whole keyword */
         switch (**data) {