docs(web),SystemVerilog: add parser-verilog.rst

docs/parser-verilog.rst

@@ -0,0 +1,73 @@
+.. _verilog:
+
+======================================================================
+Verilog/SystemVerilog parser
+======================================================================
+
+Introduction
+---------------------------------------------------------------------
+
+The Verilog/SystemVerilog parser is used for Verilog or SystemVerilog files.
+
+It assumes the input file is written in the correct grammer.  Otherwise output of
+ctags is undefined.
+
+Notable New Features
+---------------------------------------------------------------------
+
+Some of the notable new features are described below.
+
+parameter
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+If the field ``parameter`` is enabled, a tagfield ``parameter:overridden`` is added on a parameter whose
+value can be overridden on an instantiated module, interface, or program.
+
+.. code-block:: console
+
+	$ ctags ... --fields-Verilog=+{parameter} ...
+	$ ctags ... --fields-SystemVerilog=+{parameter} ...
+
+On the following source code tagfields ``parameter:overridden`` are added on
+parameter ``P*``, not on ``L*``.  Note that ``L4`` and ``L6`` is declared by
+``parameter`` statement, but tagfields ``parameter:overridden`` are not added,
+because they cannot be overridden.
+
+.. code-block:: systemverilog
+
+	// compilation unit scope
+	parameter L1 = 0;  //  synonym for the localparam
+
+	module module_with_parameter_port_list #(P1, P2, localparam L2 = P1+1, L3=P2*2, parameter P3, P4)
+		( /*port list...*/ );
+		parameter  L4 = "local parameter";  // synonym for the localparam
+		localparam L5 = "local parameter";
+		// ...
+	endmodule
+
+	module module_with_empty_parameter_port_list #()
+		( /*port list...*/ );
+		parameter  L6 = "local parameter";  // synonym for the localparam
+		localparam L7 = "local parameter";
+		// ...
+	endmodule
+
+	module module_no_parameter_port_list
+		( /*port list...*/ );
+		parameter  P5 = "parameter";
+		localparam L8 = "local parameter";
+		// ...
+	endmodule
+
+Incompatible Changes
+---------------------------------------------------------------------
+
+The parser is mostly compatible with the old one. There are some minor
+incompatible changes which are described below.
+
+TBD
+
+Known Issues
+---------------------------------------------------------------------
+
+See https://github.com/universal-ctags/ctags/issues/TBD.