shift-reduce did not work, not works (not very good) with no nonassoc

2 files changed, 38 insertions, 18 deletions

diff --git a/parts/grammar.h b/parts/grammar.h
index 4505b1a..594e61e 100644
--- a/parts/grammar.h
+++ b/parts/grammar.h
@@ -4,9 +4,9 @@
 #include <stddef.h> // size_t
 
 enum precedence_flag {
-    PRECEDENCE_NO_ASSOC,
-    PRECEDENCE_RIGHT_ASSOC,
     PRECEDENCE_LEFT_ASSOC,
+    PRECEDENCE_RIGHT_ASSOC,
+    PRECEDENCE_NO_ASSOC,
 };
 
 #define PRECEDENCE_NUM(prec) ((prec) >> 2)
diff --git a/parts/table.h b/parts/table.h
index ff4601f..01a6bbf 100644
--- a/parts/table.h
+++ b/parts/table.h
@@ -9,7 +9,8 @@
     X(ACTION_SHIFT)    \
     X(ACTION_GOTO)     \
     X(ACTION_REDUCE)   \
-    X(ACTION_ACCEPT)
+    X(ACTION_ACCEPT)   \
+    X(ACTION_ERROR)
 
 const char * const action_type_to_char[] = {
     ACTION_TYPE(X_TO_STR)
@@ -37,7 +38,7 @@ void table_print()
     for(size_t sym = 0; sym < total_symbols; sym++) printf("%2zu  ", sym);
     printf("\n");
 
-    char action_to_char[] = {[ACTION_SHIFT] = 's', [ACTION_REDUCE] = 'r', [ACTION_GOTO] = 'g'};
+    char action_to_char[] = {[ACTION_SHIFT] = 's', [ACTION_REDUCE] = 'r', [ACTION_GOTO] = 'g', [ACTION_ERROR] = 'e'};
     for(size_t i = 0; i < table_states; i++) {
         printf("%2zu  ", i);
         for(size_t sym = 0; sym < total_symbols; sym++)
@@ -73,36 +74,55 @@ int table_insert(size_t state, symbol sym, struct action a)
     }
 
     int r = 0, report = 0, set_tbl_a = 0,
-    reduce_reduce = 0, shift_reduce = 0;
-    struct action *shift_a;
+        reduce_reduce = 0, shift_reduce = 0,
+        shift_p, reduce_p, tbl_is_reduce;
 
     if((tbl_a->type == ACTION_REDUCE && new_a->type == ACTION_REDUCE))       reduce_reduce = 1;
     else if((tbl_a->type == ACTION_REDUCE && new_a->type == ACTION_SHIFT))   { shift_reduce = 1;
-        shift_a = new_a;
+        tbl_is_reduce = 1;
     } else if((tbl_a->type == ACTION_SHIFT && new_a->type == ACTION_REDUCE)) { shift_reduce = 1;
-        shift_a = tbl_a;
+        tbl_is_reduce = 0;
+    }
+
+    // bad hack to get precedence of the symbol
+    if(shift_reduce) {
+        for(size_t i = 0; i < total_productions; i++)
+            for(size_t j = 0; j < grammar[i].nRHS; j++)
+                if(grammar[i].RHS[j] == sym) {
+                    shift_p = grammar[i].precedence;
+                    goto out;
+                }
+    out:
+        if(tbl_is_reduce) reduce_p = grammar[tbl_a->arg].precedence;
+        else reduce_p = grammar[new_a->arg].precedence;
     }
 
 #define prec_num(a)  PRECEDENCE_NUM(grammar[(a)->arg].precedence)
 #define prec_flag(a) PRECEDENCE_FLAG(grammar[(a)->arg].precedence)
 
-    if(reduce_reduce || shift_reduce) {
+    if(reduce_reduce) {
         if(prec_num(tbl_a) == 0 || prec_num(new_a) == 0) report = 1;
 
         if(prec_num(tbl_a) > prec_num(new_a))      set_tbl_a = 0;
         else if(prec_num(tbl_a) < prec_num(new_a)) set_tbl_a = 1;
-        else if(reduce_reduce) {
+        else {
             report = 1;
             if(new_a->arg > tbl_a->arg) set_tbl_a = 1;
-        } else {
-            if(prec_flag(tbl_a) == PRECEDENCE_NO_ASSOC && tbl_a->arg == new_a->arg) {
-                report = 1; r = 2;
-            } else if(prec_flag(shift_a) == PRECEDENCE_LEFT_ASSOC) {
-                if(shift_a == tbl_a) set_tbl_a = 1; // favor reduce
-            }else {
-                if(shift_a == new_a) set_tbl_a = 1; // favor shift
-            }
         }
+    } else if(shift_reduce) {
+        int favor_shift = 0;
+        if(shift_p == 0 || reduce_p == 0) { favor_shift = 1; report = 1; }
+        else if(PRECEDENCE_NUM(shift_p) > PRECEDENCE_NUM(reduce_p)) favor_shift = 1;
+        else if(PRECEDENCE_NUM(reduce_p) > PRECEDENCE_NUM(shift_p)) favor_shift = 1;
+        else {
+            if(PRECEDENCE_FLAG(shift_p) == PRECEDENCE_LEFT_ASSOC)       favor_shift = 1;
+            else if(PRECEDENCE_FLAG(shift_p) == PRECEDENCE_RIGHT_ASSOC) favor_shift = 0;
+            // else if(PRECEDENCE_FLAG(shift_p)  == PRECEDENCE_NO_ASSOC &&
+                    // PRECEDENCE_FLAG(reduce_p) == PRECEDENCE_NO_ASSOC) { set_tbl_a = 1; a.type = ACTION_ERROR; a.arg = 0; }
+            else { favor_shift = 1, report = 1; }
+        }
+
+        if(favor_shift && tbl_is_reduce || !favor_shift && !tbl_is_reduce) set_tbl_a = 1;
     } else {
         r = 1; report = 1;
     }