Wide Coverage Demo App: translate to all available target langauges at once

This means that the new translation is available instantly when switching
target languages. It can also reduce space leaks problems in the server
somewhat by avoiding repeated parsing of the source text.

src/www/js/gftranslate.js

@@ -13,6 +13,12 @@ gftranslate.call=function(querystring,cont) {
     http_get_json(gftranslate.jsonurl+querystring,cont,errcont)
 }
 
+function enc_langs(g,to) {
+    return Array.isArray(to)
+             ? to.map(function(l){return g+l}).join("+")
+	     : g+to
+}
+
 // Translate a sentence
 gftranslate.translate=function(source,from,to,start,limit,cont) {
     var g=gftranslate.grammar
@@ -22,7 +28,7 @@ gftranslate.translate=function(source,from,to,start,limit,cont) {
     function extract(result) { cont(result[0].translations) }
     if(encsrc.length<500)
 	gftranslate.call("?command=c-translate&input="+encsrc
-		      +lexer+"&unlexer=text&from="+g+from+"&to="+g+to
+		      +lexer+"&unlexer=text&from="+g+from+"&to="+enc_langs(g,to)
 		      +"&start="+start+"&limit="+limit,extract)
     else cont([{error:"sentence too long"}])
 }
@@ -34,9 +40,10 @@ gftranslate.wordforword=function(source,from,to,cont) {
     if(from=="Chi") lexer="",source=source.split("").join(" ")
     var encsrc=encodeURIComponent(source)
     function extract(result) { cont(result[0].translations) }
+    var enc_to = enc_langs(g,to)
     if(encsrc.length<500)
 	gftranslate.call("?command=c-wordforword&input="+encsrc
-			 +lexer+"&unlexer=text&from="+g+from+"&to="+g+to
+			 +lexer+"&unlexer=text&from="+g+from+"&to="+enc_to
 			 ,extract)
     else cont([{error:"sentence too long"}])
 }
@@ -77,12 +84,20 @@ function trans_text_quality(text) {
     return {quality:quality,text:text}
 }
 
-function trans_quality(r) {
-    var text=r.linearizations[0].text
+// find_to :: Lang -> [{to:Lang,...}] -> Int
+find_to=function(to,lins) {
+    for(var i=0;i<lins.length;i++)
+	if(lins[i].to==to) return i
+    return 0 // Hmm....
+}
+
+trans_quality=function(r,to) {
+    var ix=to ? find_to(to,r.linearizations) : 0
+    var text=r.linearizations[ix].text
     if(r.prob==0) return {quality:"high_quality",text:text}
     else {
 	var t=trans_text_quality(text)
-	if(t.quality=="default_quality" && r.tree[0]=="?")
+	if(t.quality=="default_quality" && r.tree && r.tree[0]=="?")
 	    t.quality="low_quality"
 	return t
     }