address pr comments remove matrix subscript grammar, update accessor grammar to be inclusive to swizzling, and simplify memory style accessor description.

Author: farzonl

specs/language/expressions.tex

@@ -169,22 +169,35 @@
 
 \Sec{Matrix Member Expression(s)}{Expr.Post.Member.Matrix}
 \begin{grammar}
-  \define{postfix-expression}\br
-  primary-expression\br
-  postfix-expression [ expression ][ expression ]\br %
-  postfix-expression matrix-zero-indexed-accessor\br
-  postfix-expression matrix-one-indexed-accessor\br
+  \define {matrix-accessor-sequence}\br
+  matrix-zero-indexed-accessor-sequence\br
+  matrix-one-indexed-accessor-sequence\br
+
+  \define{matrix-zero-indexed-accessor-sequence}\br
+  matrix-zero-indexed-accessor\br
+  matrix-zero-indexed-accessor-sequence matrix-zero-indexed-accessor\br
+
   \define{matrix-zero-indexed-accessor}\br
-    \opt{matrix-zero-indexed-accessor} \terminal{\_m} integer-literal\br
+  \terminal{\_m} zero-index-value\br
+
+  \define{zero-index-value}\br
+  \terminal{0 1 2 3 }\br
+
+  \define{matrix-one-indexed-accessor-sequence}\br
+  matrix-one-indexed-accessor\br
+  matrix-one-indexed-accessor-sequence matrix-one-indexed-accessor\br
+
   \define{matrix-one-indexed-accessor}\br
-    \opt{matrix-one-indexed-accessor} \terminal{\_} integer-literal\br
+  \terminal{\_m} one-index-value\br
+
+  \define{one-index-value}\br
+  \terminal{1 2 3 4 }\br
 \end{grammar}
 \begin{itemize}
 \item \textbf{.\_} (math-style): subsequent subscripts use \textbf{1-based}
  indexing for both row and column.
 \item \textbf{.\_m} (memory-style): subsequent subscripts use \textbf{0-based}
- indexing for both row and column. This is equivalent to the double square
- brackets subscript expression of the form \texttt{E0[E1][E2]}.
+ indexing for both row and column.
 \end{itemize}
 
 \Sec{Function Calls}{Expr.Post.Call}