code suggestions

src/main/java/carpet/script/ExpressionInspector.java

@@ -1,6 +1,13 @@
 package carpet.script;
 
+import carpet.CarpetServer;
+import org.apache.commons.lang3.StringUtils;
+
+import java.util.Collections;
 import java.util.List;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.stream.Collectors;
 
 /**
  * sole purpose of this package is to provide public access to package-private methods of Expression and CarpetExpression
@@ -17,4 +24,29 @@ public class ExpressionInspector
     {
         return e.getName();
     }
+
+    private static TreeSet<String> scarpetFunctions;
+    private static TreeSet<String> APIFunctions;
+    static
+    {
+        Set<String> allFunctions = (new CarpetExpression("null", null, null)).getExpr().getFunctionNames();
+        scarpetFunctions = new TreeSet<>(new Expression("null").getFunctionNames());
+        APIFunctions = new TreeSet<>(allFunctions.stream().filter(s -> !scarpetFunctions.contains(s)).collect(Collectors.toSet()));
+    }
+
+    public static List<String> suggestFunctions(String previous, String prefix)
+    {
+        previous = previous.replace("\\'", "");
+        int quoteCount = StringUtils.countMatches(previous,'\'');
+        if (quoteCount % 2 == 1)
+            return Collections.emptyList();
+        int maxLen = prefix.length()<3 ? (prefix.length()*2+1) : 1234;
+        List<String> scarpetMatches = scarpetFunctions.stream().
+                filter(s -> s.startsWith(prefix) && s.length() <= maxLen).map(s -> s+"(").collect(Collectors.toList());
+        scarpetMatches.addAll(APIFunctions.stream().
+                filter(s -> s.startsWith(prefix) && s.length() <= maxLen).map(s -> s+"(").collect(Collectors.toList()));
+        scarpetMatches.addAll(CarpetServer.scriptServer.globalHost.globalVariables.keySet().stream().
+                filter(s -> s.startsWith(prefix)).collect(Collectors.toList()));
+        return scarpetMatches;
+    }
 }