static boolean findFunctionInvocations_debug;

// these prefix tokens mark a non-invocation (TODO: expand)
static Set<S> findFunctionInvocations_pre = new HashSet(litlist(".", "void", "S", "String", "int", "bool", "boolean", "A", "Object", "O", "]", "double", "float", "short", "char", "long"));

static Set<String> findFunctionInvocations(S src, SS sf) {
  ret findFunctionInvocations(javaTok(src), sf);
}

static Set<String> findFunctionInvocations(L<S> tok, SS sf) {
  ret findFunctionInvocations(tok, sf, null);
}

// sf = set of functions to search for or null for any function
static Set<String> findFunctionInvocations(L<S> tok, SS sf, Collection<S> hardReferences) {
  ret findFunctionInvocations(tok, sf, hardReferences, null);
}

static Set<String> findFunctionInvocations(L<S> tok, SS sf, Collection<S> hardReferences, Set<S> haveFunctions) {
  ret findFunctionInvocations(tok, sf, hardReferences, haveFunctions, false);
}

// tok: the code
// sf: map of functions (keys) to look for - null to record every function call
// hardReferences (out parameter): records every "please include"  statement if not null
// haveFunctions: functions to skip (or null)
// includePossiblyMapLikes: include calls with pre-brackets argument (e.g. map l(...))
// mainClassName: name of program's main class (calls to this class will be skipped)
static Set<S> findFunctionInvocations(LS tok, SS sf, Cl<S> hardReferences, Set<S> haveFunctions, bool includePossiblyMapLikes, S mainClassName default "main") {
  new LinkedHashSet<S> l;
  for (int i : jfindAll(tok, "please include functions")) {
    int j = i + 6;
    while licensed {
      String fname = tok.get(j);
      assertIdentifier("in please include functions section", get(tok, j));
      l.add(fname);
      add(hardReferences, fname);
      j += 2;
      if (eqGet(tok, j, ".")) break;
      while (eqGetOneOf(tok, j, ",", "and")) j += 2;
    }
    clearAllTokens(tok.subList(i, j+2));
  }
  
  for (int i : jfindAll(tok, "please include function *.")) {
    String fname = tok.get(i+6);
    l.add(fname);
    add(hardReferences, fname);
    clearAllTokens(tok.subList(i, i+10));
  }

  int i, n = tok.size();
  boolean result = false;
  for (i = 1; i+2 < n; i += 2) {
    S f = tok.get(i);
    if (!isIdentifier_quick(f)) continue;
    
    // main.<A>bla()
    if (eq(mainClassName, f) && eq(tok.get(i+2), ".") && eqGet(tok, i+4, "<")) {
      i = findEndOfTypeArgs(tok, i+4)+1;
      f = tok.get(i);
      if (!isIdentifier(f)) continue;
    }
    
    if (findFunctionInvocations_debug)
      print("Testing identifier " + f);
      
    // e.g. ... html_findLIs(LS [auto htmlTok] tok) { ... }
    if (eqGet(tok, i-4, "[") && eqGet(tok, i-2, "auto")) {
      // ok
    } else if (eqGet(tok, i-2, ":") && eqGet(tok, i-4, ":") && eqGet(tok, i-6, mainClassName)) {
      // ok, function reference (main::bla)
    } else if (eqGet(tok, i+2, "(")) {
      // ok, normal function invocation
    } else if (includePossiblyMapLikes && eqGet(tok, i+4, "(") && isIdentifier(get(tok, i+2))) {
      // ok, mapLike invocation (bla blubb(...))
    } else
      // not an invocation
      continue;

    if (i == 1
        || !findFunctionInvocations_pre.contains(tok.get(i-2))
        || eqGet(tok, i-2, ".") && eqGet(tok, i-4, mainClassName)) {
      boolean inSF = sf == null || sf.containsKey(f);
      if (findFunctionInvocations_debug)
        print("Possible invocation: " + f + ", inSF: " + inSF);
      if (inSF && !contains(haveFunctions, f) && l.add(f))
        if (findFunctionInvocations_debug)
          print("Found reference to standard function " + f + ": " + lineAroundToken(tok, i));
    }
  }
  
  return l;
}