tools,doc: fix json for grouped optional params

Current tools/doc/json.js only supports one bracket style for optional
params methodName(param0[,param1],param2). Add support to other styles
such as methodName(param0,[param1,]param2) or
methodName(param0[,param1,param2]) or
methodName(param0[,param1[,param2]]).
PR-URL: #5977Fixes: #5976
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Robert Lindstädt <robert.lindstaedt@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>

Author: firedfox

tools/doc/json.js

@@ -280,21 +280,30 @@ function parseSignature(text, sig) {
 varparams=text.match(paramExpr);
 if(!params)return;
 params=params[1];
-// the [ is irrelevant. ] indicates optionalness.
-params=params.replace(/\[/g,'');
 params=params.split(/,/);
+varoptionalLevel=0;
+varoptionalCharDict={'[': 1,' ': 0,']': -1};
 params.forEach(function(p,i,_){
 p=p.trim();
 if(!p)return;
 varparam=sig.params[i];
 varoptional=false;
 vardef;
-// [foo] -> optional
-if(p.charAt(p.length-1)===']'){
-optional=true;
-p=p.replace(/\]/g,'');
-p=p.trim();
+
+// for grouped optional params such as someMethod(a[, b[, c]])
+varpos;
+for(pos=0;pos<p.length;pos++){
+if(optionalCharDict[p[pos]]===undefined){break;}
+optionalLevel+=optionalCharDict[p[pos]];
+}
+p=p.substring(pos);
+optional=(optionalLevel>0);
+for(pos=p.length-1;pos>=0;pos--){
+if(optionalCharDict[p[pos]]===undefined){break;}
+optionalLevel+=optionalCharDict[p[pos]];
 }
+p=p.substring(0,pos+1);
+
 vareq=p.indexOf('=');
 if(eq!==-1){
 def=p.substr(eq+1);