Changes between Version 5 and Version 6 of Taskforces/FCS/FCS-QL

Timestamp:

08/05/15 12:40:31 (9 years ago)

Author:

peter.beinema@mpi.nl

Comment:

--

Taskforces/FCS/FCS-QL

@@ -114 +114 @@
  * rule 5: option marker '?' makes "[]" a valid query. Propose to remove question mark.
  * expression [11] / basic expression [12]: structural ambiguity. See proposed alternative below.
+== ENBF ==
 {{{
-// rules presented in antlr format
-//--- [2v2] no left recursion or ambiguity, 1 (optional) quantifier
-main_query :
-      simple_query
-    | simple_query '|' main_query       // 'or'
-    | simple_query main_query           // sequence
-    | simple_query quantifier           // quantification
-    ;
+[2 v2]   /* in combination with [3 v2] no more left recursion or ambiguity, max 1 quantifier per simple-query */
+main-query ::=
+      simple-query
+    | simple-query '|' main-query       /* 'or' */
+    | simple-query main-query           /* sequence */
+    | simple-query quantifier           /* quantification */
 
-//--- [3v2]
-simple_query :
-      '(' main_query ')'
-    | implicit_query
-    | segment_query
-    ;
+[3 v2]
 
-//--- [5v2] 'expression no longer optional
-segment_query :
+simple_query ::=
+      '(' main_query ')'  /* embedding moved from main-query to simple-query
+    | implicit-query
+    | segment-query
+
+[5 v2]  /* expression no longer optional */
+segment-query :
       '[' expression ']'
-    ;
 
-//--- [11v2]
+[11 v2]  /* in combination with [12 v2] no longer left recursive or ambiguous
 expression :
-      basic_expression
-    | basic_expression '|' expression   // or
-    | basic_expression '&' expression   // and
-    ;
+      basic-expression
+    | basic-expression '|' expression   // or
+    | basic-expression '&' expression   // and
 
-//--- [12v2]
-basic_expression :
+[12 v2]
+basic-expression :
       '(' expression ')'        // grouping
     | '!' expression            // not
     | attribute operator flagged_regexp
-    ;
 
 }}}