support for $comment, $date, $timescale, $version

test/basic.js

@@ -32,6 +32,7 @@ describe('basic', () => {
       ' \n $comment some text $end $comment more text $end ???'
     ))).to.eq(true);
     expect(inst.info).to.deep.eq({
+      comment: ' more text ',
       stack: [{}],
       status: 'declaration',
       wires: {}
@@ -81,6 +82,9 @@ b0000000000001111 {u
 
     expect(inst.info).to.deep.eq({
       status: 'simulation',
+      date: ' Wed Sep 18 22:59:07 2019\n ',
+      version: ' Generated by VerilatedVcd ',
+      timescale: '   1ns ',
       varId: 'u)',
       wires: {
         top: {

test/events.js

@@ -10,6 +10,9 @@ describe('events', () => {
     inst.on('$enddefinitions', () => {
       expect(inst.info).to.deep.eq({
         status: 'simulation',
+        date: ' Wed Sep 18 22:59:07 2019\n ',
+        version: ' Generated by VerilatedVcd ',
+        timescale: '   1ns ',
         varId: 'u)',
         wires: {
           top: {

test/wasm_basic.js

@@ -31,6 +31,7 @@ describe('wasm basic', () => {
       ' \n $comment some text $end $comment more text $end ???'
     ))).to.eq(true);
     expect(inst.info).to.deep.eq({
+      comment: ' more text ',
       stack: [{}],
       status: 'declaration',
       wires: {}
@@ -79,6 +80,9 @@ b0000000000001111 {u
 
     expect(inst.info).to.deep.eq({
       status: 'simulation',
+      date: ' Wed Sep 18 22:59:07 2019\n ',
+      version: ' Generated by VerilatedVcd ',
+      timescale: '   1ns ',
       varId: 'u)',
       wires: {
         top: {

test/wasm_events.js

@@ -18,6 +18,9 @@ describe('wasm events', () => {
     inst.on('$enddefinitions', () => {
       expect(inst.info).to.deep.eq({
         status: 'simulation',
+        timescale: '   1ns ',
+        date: ' Wed Sep 18 22:59:07 2019\n ',
+        version: ' Generated by VerilatedVcd ',
         varId: 'u)',
         wires: {
           top: {

vcd_spans.c

@@ -74,6 +74,30 @@ int commandSpan(vcd_parser_t* state, const unsigned char* p, const unsigned char
     return 0;
   }
 
+  if (
+    (state->command == 1) || // $comment
+    (state->command == 2) || // $date
+    (state->command == 4) || // $timescale
+    (state->command == 7)    // $version
+  ) {
+    char* key;
+    switch(state->command) {
+    case 1: key = "comment"; break;
+    case 2: key = "date"; break;
+    case 4: key = "timescale"; break;
+    case 7: key = "version"; break;
+    }
+#ifndef VCDWASM
+    napi_value val;
+    ASSERT(val, napi_create_string_latin1(env, (char*)p, (endp - p - 4), &val))
+    ASSERT(state->info, napi_set_named_property(env, state->info, key, val))
+#else
+    strcopy(p, endp - 3, state->tmpStr);
+    set_property_string(key, state->tmpStr);
+#endif
+    return 0;
+  }
+
   if (state->command == 8) { // $enddefinitions
 #ifndef VCDWASM
     napi_value status, undefined, eventName, eventPayload, return_val;