From 8255f3f9fe76554e837e557463ee2f5bf69d74d5 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Mon, 25 May 2020 18:41:47 -0400
Subject: [PATCH] Internals: Parser cleanup of parameters, first part.

---
 src/V3LinkParse.cpp |  4 ++++
 src/verilog.y       | 16 +++++++++-------
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/V3LinkParse.cpp b/src/V3LinkParse.cpp
index ed78d7546..aae9f23c3 100644
--- a/src/V3LinkParse.cpp
+++ b/src/V3LinkParse.cpp
@@ -173,6 +173,10 @@ private:
 
     virtual void visit(AstVar* nodep) VL_OVERRIDE {
         cleanFileline(nodep);
+        if (nodep->isParam() && !nodep->valuep()
+            && nodep->fileline()->language() < V3LangCode::L1800_2009) {
+            nodep->v3error("Parameter requires default value, or use IEEE 1800-2009 or later.");
+        }
         if (VN_IS(nodep->subDTypep(), ParseTypeDType)) {
             // It's a parameter type. Use a different node type for this.
             AstNodeDType* dtypep = VN_CAST(nodep->valuep(), NodeDType);
diff --git a/src/verilog.y b/src/verilog.y
index 908a8a720..28ab64e8c 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -2431,12 +2431,14 @@ packed_dimension<rangep>:	// ==IEEE: packed_dimension
 param_assignment<varp>:		// ==IEEE: param_assignment
 	//			// IEEE: constant_param_expression
 	//			// constant_param_expression: '$' is in expr
-		id/*new-parameter*/ variable_dimensionListE sigAttrListE '=' expr
-	/**/		{ $$ = VARDONEA($<fl>1,*$1, $2, $3); $$->valuep($5); }
-	|	id/*new-parameter*/ variable_dimensionListE sigAttrListE
-	/**/		{ $$ = VARDONEA($<fl>1,*$1, $2, $3);
-		          if ($<fl>1->language() < V3LangCode::L1800_2009) {
-			     $<fl>1->v3error("Parameter requires default value, or use IEEE 1800-2009 or later."); } }
+		id/*new-parameter*/ variable_dimensionListE sigAttrListE param_assignmentEqE
+			{ $$ = VARDONEA($<fl>1, *$1, $2, $3); if ($4) $$->valuep($4); }
+	;
+
+param_assignmentEqE<nodep>:	//IEEE: part of param_assignment ('=' expr or empty)
+	//			// constant_param_expression: '$' is in expr
+		/*empty*/				{ $$ = NULL; }
+	|	'=' expr				{ $$ = $2; }
 	;
 
 list_of_param_assignments<varp>:	// ==IEEE: list_of_param_assignments
@@ -2447,7 +2449,7 @@ list_of_param_assignments<varp>:	// ==IEEE: list_of_param_assignments
 type_assignment<varp>:		// ==IEEE: type_assignment
 	//			// note exptOrDataType being a data_type is only for yPARAMETER yTYPE
 		idAny/*new-parameter*/ sigAttrListE '=' data_type
-	/**/		{ $$ = VARDONEA($<fl>1,*$1, NULL, $2); $$->valuep($4); }
+			{ $$ = VARDONEA($<fl>1, *$1, NULL, $2); $$->valuep($4); }
 	;
 
 list_of_type_assignments<varp>:		// ==IEEE: list_of_type_assignments