chore: improve error message when missing stdlib

https://github.com/plantuml/plantuml/pull/1692#issuecomment-1952831187

src/net/sourceforge/plantuml/preproc/Stdlib.java

@@ -332,6 +332,9 @@ public class Stdlib {
 	private static Collection<String> getAll() throws IOException {
 		final Set<String> result = new TreeSet<>();
 		final InputStream home = getInternalInputStream("home", ".repx");
+		if (home == null)
+			throw new IOException("Cannot access to /stdlib/*.repx files");
+
 		final BufferedReader br = new BufferedReader(new InputStreamReader(home));
 		String name;
 		while ((name = br.readLine()) != null)

src/net/sourceforge/plantuml/tim/TFunctionImpl.java

@@ -69,6 +69,7 @@ public class TFunctionImpl implements TFunction {
 		this.functionType = functionType;
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArguments) {
 		for (String n : namedArguments)
 			if (signature.getNamedArguments().contains(n) == false)
@@ -140,8 +141,9 @@ public class TFunctionImpl implements TFunction {
 		context.executeLines(copy, body, TFunctionType.PROCEDURE, false);
 	}
 
-	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> args,
-			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
+	@Override
+	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location,
+			List<TValue> args, Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		if (functionType == TFunctionType.LEGACY_DEFINE)
 			return executeReturnLegacyDefine(location, context, memory, args);
 

src/net/sourceforge/plantuml/tim/stdlib/AlwaysFalse.java

@@ -52,10 +52,12 @@ public class AlwaysFalse extends SimpleReturnFunction {
 		return new TFunctionSignature("%false", 0);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0;
 	}
-
+	
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		return TValue.fromBoolean(false);

src/net/sourceforge/plantuml/tim/stdlib/AlwaysTrue.java

@@ -52,10 +52,12 @@ public class AlwaysTrue extends SimpleReturnFunction {
 		return new TFunctionSignature("%true", 0);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		return TValue.fromBoolean(true);

src/net/sourceforge/plantuml/tim/stdlib/CallUserFunction.java

@@ -53,10 +53,12 @@ public class CallUserFunction extends SimpleReturnFunction {
 		return new TFunctionSignature("%call_user_func", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg > 0;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String fname = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/Chr.java

@@ -52,10 +52,12 @@ public class Chr extends SimpleReturnFunction {
 		return new TFunctionSignature("%chr", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		try {

src/net/sourceforge/plantuml/tim/stdlib/Darken.java

@@ -56,10 +56,12 @@ public class Darken extends SimpleReturnFunction {
 		return new TFunctionSignature("%darken", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String colorString = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/DateFunction.java

@@ -54,10 +54,12 @@ public class DateFunction extends SimpleReturnFunction {
 		return new TFunctionSignature("%date", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0 || nbArg == 1 || nbArg == 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		if (values.size() == 0)

src/net/sourceforge/plantuml/tim/stdlib/Dec2hex.java

@@ -52,10 +52,12 @@ public class Dec2hex extends SimpleReturnFunction {
 		return new TFunctionSignature("%dec2hex", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		try {

src/net/sourceforge/plantuml/tim/stdlib/Dirpath.java

@@ -59,10 +59,12 @@ public class Dirpath extends SimpleReturnFunction {
 		return new TFunctionSignature("%dirpath", 0);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		if (value == null) {

src/net/sourceforge/plantuml/tim/stdlib/Eval.java

@@ -53,10 +53,12 @@ public class Eval extends SimpleReturnFunction {
 		return new TFunctionSignature("%eval", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String exp = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/Feature.java

@@ -52,10 +52,12 @@ public class Feature extends SimpleReturnFunction {
 		return new TFunctionSignature("%feature", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String arg = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/FileExists.java

@@ -53,10 +53,12 @@ public class FileExists extends SimpleReturnFunction {
 		return new TFunctionSignature("%file_exists", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		// ::comment when __CORE__

src/net/sourceforge/plantuml/tim/stdlib/Filename.java

@@ -59,10 +59,12 @@ public class Filename extends SimpleReturnFunction {
 		return new TFunctionSignature("%filename", 0);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		if (value == null) {

src/net/sourceforge/plantuml/tim/stdlib/FunctionExists.java

@@ -53,10 +53,12 @@ public class FunctionExists extends SimpleReturnFunction {
 		return new TFunctionSignature("%function_exists", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String name = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/GetAllTheme.java

@@ -56,10 +56,12 @@ public class GetAllTheme extends SimpleReturnFunction {
 		return new TFunctionSignature("%get_all_theme", 0);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final JsonArray result = new JsonArray();

src/net/sourceforge/plantuml/tim/stdlib/GetJsonKey.java

@@ -55,10 +55,12 @@ public class GetJsonKey extends SimpleReturnFunction {
 		return new TFunctionSignature("%get_json_keys", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final TValue data = values.get(0);

src/net/sourceforge/plantuml/tim/stdlib/GetJsonType.java

@@ -53,10 +53,12 @@ public class GetJsonType extends SimpleReturnFunction {
 		return new TFunctionSignature("%get_json_type", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final TValue data = values.get(0);

src/net/sourceforge/plantuml/tim/stdlib/GetVariableValue.java

@@ -52,10 +52,12 @@ public class GetVariableValue extends SimpleReturnFunction {
 		return new TFunctionSignature("%get_variable_value", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String name = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/GetVersion.java

@@ -53,10 +53,12 @@ public class GetVersion extends SimpleReturnFunction {
 		return new TFunctionSignature("%version", 0);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		return TValue.fromString(Version.versionString());

src/net/sourceforge/plantuml/tim/stdlib/Getenv.java

@@ -53,10 +53,12 @@ public class Getenv extends SimpleReturnFunction {
 		return new TFunctionSignature("%getenv", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		// ::comment when __CORE__

src/net/sourceforge/plantuml/tim/stdlib/Hex2dec.java

@@ -52,10 +52,12 @@ public class Hex2dec extends SimpleReturnFunction {
 		return new TFunctionSignature("%hex2dec", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		try {

src/net/sourceforge/plantuml/tim/stdlib/HslColor.java

@@ -55,10 +55,12 @@ public class HslColor extends SimpleReturnFunction {
 		return new TFunctionSignature("%hsl_color", 3);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 3 || nbArg == 4;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final int h = values.get(0).toInt();

src/net/sourceforge/plantuml/tim/stdlib/IntVal.java

@@ -53,10 +53,12 @@ public class IntVal extends SimpleReturnFunction {
 		return new TFunctionSignature("%intval", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String s = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/InvokeProcedure.java

@@ -54,6 +54,7 @@ public class InvokeProcedure implements TFunction {
 		return new TFunctionSignature("%invoke_procedure", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg > 0;
 	}
@@ -75,6 +76,7 @@ public class InvokeProcedure implements TFunction {
 		func.executeProcedureInternal(context, memory, sublist, named);
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) {
 		throw new UnsupportedOperationException();

src/net/sourceforge/plantuml/tim/stdlib/IsDark.java

@@ -56,10 +56,12 @@ public class IsDark extends SimpleReturnFunction {
 		return new TFunctionSignature("%is_dark", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String colorString = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/IsLight.java

@@ -56,10 +56,12 @@ public class IsLight extends SimpleReturnFunction {
 		return new TFunctionSignature("%is_light", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String colorString = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/JsonKeyExists.java

@@ -54,10 +54,12 @@ public class JsonKeyExists extends SimpleReturnFunction {
 		return new TFunctionSignature("%json_key_exists", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final TValue arg0 = values.get(0);

src/net/sourceforge/plantuml/tim/stdlib/Lighten.java

@@ -56,10 +56,12 @@ public class Lighten extends SimpleReturnFunction {
 		return new TFunctionSignature("%lighten", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String colorString = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/LoadJson.java

@@ -102,10 +102,12 @@ public class LoadJson extends SimpleReturnFunction {
 		return new TFunctionSignature("%load_json", 3);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1 || nbArg == 2 || nbArg == 3;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String path = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/LogicalAnd.java

@@ -52,10 +52,12 @@ public class LogicalAnd extends SimpleReturnFunction {
 		return new TFunctionSignature("%and", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg >= 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		for (TValue v : values)

src/net/sourceforge/plantuml/tim/stdlib/LogicalNand.java

@@ -52,10 +52,12 @@ public class LogicalNand extends SimpleReturnFunction {
 		return new TFunctionSignature("%nand", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg >= 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		for (TValue v : values)

src/net/sourceforge/plantuml/tim/stdlib/LogicalNor.java

@@ -52,10 +52,12 @@ public class LogicalNor extends SimpleReturnFunction {
 		return new TFunctionSignature("%nor", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg >= 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		for (TValue v : values)

src/net/sourceforge/plantuml/tim/stdlib/LogicalNot.java

@@ -52,10 +52,12 @@ public class LogicalNot extends SimpleReturnFunction {
 		return new TFunctionSignature("%not", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final boolean arg = values.get(0).toBoolean();

src/net/sourceforge/plantuml/tim/stdlib/LogicalNxor.java

@@ -52,10 +52,12 @@ public class LogicalNxor extends SimpleReturnFunction {
 		return new TFunctionSignature("%nxor", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg >= 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		int cpt = 0;

src/net/sourceforge/plantuml/tim/stdlib/LogicalOr.java

@@ -52,10 +52,12 @@ public class LogicalOr extends SimpleReturnFunction {
 		return new TFunctionSignature("%or", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg >= 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		for (TValue v : values)

src/net/sourceforge/plantuml/tim/stdlib/LogicalXor.java

@@ -52,10 +52,12 @@ public class LogicalXor extends SimpleReturnFunction {
 		return new TFunctionSignature("%xor", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg >= 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		int cpt = 0;

src/net/sourceforge/plantuml/tim/stdlib/Lower.java

@@ -50,10 +50,12 @@ public class Lower extends SimpleReturnFunction {
 		return new TFunctionSignature("%lower", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) {
 		return TValue.fromString(values.get(0).toString().toLowerCase());

src/net/sourceforge/plantuml/tim/stdlib/Newline.java

@@ -50,10 +50,12 @@ public class Newline extends SimpleReturnFunction {
 		return new TFunctionSignature("%newline", 0);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) {
 		return TValue.fromString("\n");

src/net/sourceforge/plantuml/tim/stdlib/Now.java

@@ -52,10 +52,12 @@ public class Now extends SimpleReturnFunction {
 		return new TFunctionSignature("%now", 0);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final long now = System.currentTimeMillis() / 1000L;

src/net/sourceforge/plantuml/tim/stdlib/Ord.java

@@ -52,10 +52,12 @@ public class Ord extends SimpleReturnFunction {
 		return new TFunctionSignature("%ord", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		try {

src/net/sourceforge/plantuml/tim/stdlib/RandomFunction.java

@@ -53,12 +53,14 @@ public class RandomFunction extends SimpleReturnFunction {
 		return new TFunctionSignature("%random", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 0 || nbArg == 1 || nbArg == 2;
 	}
 
 	private final Random random = new Random();
 	
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		switch (values.size()) {

src/net/sourceforge/plantuml/tim/stdlib/RetrieveProcedure.java

@@ -54,10 +54,12 @@ public class RetrieveProcedure extends SimpleReturnFunction {
 		return new TFunctionSignature("%retrieve_procedure", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg > 0;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String fname = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/ReverseColor.java

@@ -55,10 +55,12 @@ public class ReverseColor extends SimpleReturnFunction {
 		return new TFunctionSignature("%reverse_color", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String colorString = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/ReverseHsluvColor.java

@@ -55,10 +55,12 @@ public class ReverseHsluvColor extends SimpleReturnFunction {
 		return new TFunctionSignature("%reverse_hsluv_color", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String colorString = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/SetVariableValue.java

@@ -53,10 +53,12 @@ public class SetVariableValue extends SimpleReturnFunction {
 		return new TFunctionSignature("%set_variable_value", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		// if (memory instanceof TMemoryLocal) {

src/net/sourceforge/plantuml/tim/stdlib/Size.java

@@ -55,10 +55,12 @@ public class Size extends SimpleReturnFunction {
 		return new TFunctionSignature("%size", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final TValue value = values.get(0);

src/net/sourceforge/plantuml/tim/stdlib/SplitStr.java

@@ -54,10 +54,12 @@ public class SplitStr extends SimpleReturnFunction {
 		return new TFunctionSignature("%splitstr", 3);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final JsonArray result = new JsonArray();

src/net/sourceforge/plantuml/tim/stdlib/StringFunction.java

@@ -50,10 +50,12 @@ public class StringFunction extends SimpleReturnFunction {
 		return new TFunctionSignature("%string", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) {
 		return TValue.fromString(values.get(0).toString());

src/net/sourceforge/plantuml/tim/stdlib/Strlen.java

@@ -52,10 +52,12 @@ public class Strlen extends SimpleReturnFunction {
 		return new TFunctionSignature("%strlen", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		return TValue.fromInt(values.get(0).toString().length());

src/net/sourceforge/plantuml/tim/stdlib/Strpos.java

@@ -52,10 +52,12 @@ public class Strpos extends SimpleReturnFunction {
 		return new TFunctionSignature("%strpos", 2);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 2;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String full = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/Substr.java

@@ -52,10 +52,12 @@ public class Substr extends SimpleReturnFunction {
 		return new TFunctionSignature("%substr", 3);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 2 || nbArg == 3;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String full = values.get(0).toString();

src/net/sourceforge/plantuml/tim/stdlib/Upper.java

@@ -50,10 +50,12 @@ public class Upper extends SimpleReturnFunction {
 		return new TFunctionSignature("%upper", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) {
 		return TValue.fromString(values.get(0).toString().toUpperCase());

src/net/sourceforge/plantuml/tim/stdlib/VariableExists.java

@@ -52,10 +52,12 @@ public class VariableExists extends SimpleReturnFunction {
 		return new TFunctionSignature("%variable_exists", 1);
 	}
 
+	@Override
 	public boolean canCover(int nbArg, Set<String> namedArgument) {
 		return nbArg == 1;
 	}
 
+	@Override
 	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> values,
 			Map<String, TValue> named) throws EaterException, EaterExceptionLocated {
 		final String name = values.get(0).toString();