cellhelp: Add default format parse for simcells

Since `simcells.v` uses consistent formatting we can handle it specifically to help tidy up sphinx warnings about the truth tables, and instead chuck them in a code block which when printing to rst.
Also has the side effect that rst code blocks can be added manually with `//- ::` followed by a blank line.

kernel/register.cc

@@ -988,10 +988,14 @@ struct HelpPass : public Pass {
 			}
 			else if (cell_help_messages.cell_help.count(args[1])) {
 				SimHelper help_cell = cell_help_messages.cell_help.at(args[1]);
-				if (help_cell.ver == "2") {
-					log("\n    %s %s\n", help_cell.name.c_str(), help_cell.ports.c_str());
-					log("\n%s\n", help_cell.title.c_str());
-					log("%s\n", help_cell.desc.c_str());
+				if (help_cell.ver == "2" || help_cell.ver == "2a") {
+					log("\n    %s %s\n\n", help_cell.name.c_str(), help_cell.ports.c_str());
+					if (help_cell.title != "") log("%s\n", help_cell.title.c_str());
+					std::stringstream ss;
+					ss << help_cell.desc;
+					for (std::string line; std::getline(ss, line, '\n');) {
+						if (line != "::") log("%s\n", line.c_str());
+					}
 					log("Run 'help %s+' to display the Verilog model for this cell type.\n", args[1].c_str());
 					log("\n");
 				} else {

techlibs/common/cellhelp.py

@@ -36,6 +36,24 @@ def __str__(self) -> str:
         val += f'cell_code[{json.dumps(self.name + "+")}] = tempCell;'
         return val
 
+def simcells_reparse(cell: SimHelper):
+    # cut manual signature
+    cell.desc = cell.desc[3:]
+
+    # code-block truth table
+    new_desc = []
+    indent = ""
+    for line in cell.desc:
+        if line.startswith("Truth table:"):
+            indent = "   "
+            new_desc.pop()
+            new_desc.extend(["::", ""])
+        new_desc.append(indent + line)
+    cell.desc = new_desc
+
+    # set version
+    cell.ver = "2a"
+
 simHelper = SimHelper()
 
 for line in fileinput.input():
@@ -62,7 +80,12 @@ def __str__(self) -> str:
         # no module definition, ignore line
         pass
     if line.startswith("endmodule"):
+        short_filename = Path(fileinput.filename()).name
+        if simHelper.ver == "1" and short_filename == "simcells.v":
+            # default simcells parsing
+            simcells_reparse(simHelper)
         if not simHelper.desc:
+            # no help
             simHelper.desc.append("No help message for this cell type found.\n")
         print(simHelper)
         simHelper = SimHelper()