ScriQ Scripting Language

Get Started

Add the dependency to your project, e.g., for a Maven project.

    <dependency>
      <groupId>net.lizhao</groupId>
      <artifactId>scriq</artifactId>
      <version>0.0.11-multik</version>
    </dependency>

Evaluate ScriQ scripts

ScriQ is a tiny Python variant. This is an example to evaluate ScriQ scripts.

    @Test
    void testIfOrComp() {
        String code = "if True or 1==2:\n  return 3\nelse:\n  return 4";
        Evaluator eval = new Evaluator();
        var val = eval.eval(getTree(code), new HashMap<String, Value>());
        assert (val.equals(3));
    }

ScriQs allow the app to extend functions, instead of support function def in script.

1. Derive a class from Evaluator, and add public function, e.g., PV is a function return the first argument's value.

public class DemoFunc extends Evaluator {

    public Value PV(Value i) {
        return new Value(i);
    }
}

2. The script then can use the function:

i = 10
j = PV(i)
return j

Set Evaluation Context Memory

Second argument to eval(tree, map) is a map from String to Value. The String can be a variable name, which is recognised by the script as a variable in execution context.

    @Test
    void testEnv() {
        String code = "return i+j";
        Evaluator eval = new Evaluator();
        var map = new HashMap<String, Value>();
        map.put("i", new Value(BigDecimal.valueOf(2.1)));
        map.put("j", new Value(BigDecimal.valueOf(2.43)));
        var val = eval.eval(getTree(code), map);
        assert (val.equals(4.53));
    }

Retrospect Evaluation

ScriQ can record the arguments used calling a function, by giving the function start index in the script string. This is handy when the app needs to debug/analyze the execution.

    @Test
    void testFuncData() {
        String code = "j=PV(33,1)\ni=11\nPV(i,2)\nreturn i";
        DemoFunc eval = new DemoFunc();
        Map<Integer, Object> posMap = new HashMap<Integer, Object>();
        var val = eval.eval(getTree(code), new HashMap<String, Value>(), posMap);
        assert (val.equals(11));
        assert (((Value[])posMap.get(2))[0].equals(33));
        assert (((Value[])posMap.get(2))[1].equals(1));
        assert (((Value[])posMap.get(16))[0].equals(11));
        assert (((Value[])posMap.get(16))[1].equals(2));
    }

ScriQ also allows to preset argument values for each function calling.

    @Test
    void testPresetFuncArgs() {
        String code = "j=PV(10,1)\nreturn j";
        Map<Integer, Object> treeMap = new HashMap<Integer, Object>();
        treeMap.put(2, new Value[]{new Value(BigDecimal.valueOf(50)), new Value(BigDecimal.valueOf(0))});
        DemoFunc eval = new DemoFunc();
        var val = eval.eval(getTree(code), new HashMap<String, Value>(), treeMap);
        assert (val.equals(50));
    }

View of Grammar Tree

Serializer like Jackson ObjectMapper could be use to stringify the treeMap into json string.

    @Test
    void testTree() {
        String code = "j=PV(33,1)\ni=11\nPV(i,2)\nreturn i";
        Map<String, Object> treeMap = new HashMap<String, Object>();
        Evaluator.genTree(getTree(code), treeMap);
        assert (treeMap.size()>0);
    }

Async Programming

# power operator allows left operand to be Future, i.e, a
a ** b
# +, -, *, / operators support Future as any operand

    // define function in class derived from Evaluator
    public CompletableFuture<Value> getIntAsync() throws InterruptedException {
        CompletableFuture<Value> completableFuture = new CompletableFuture<>();

        Executors.newCachedThreadPool().submit(() -> {
            Thread.sleep(500);
            completableFuture.complete(new Value(new BigDecimal(2.0)));
            return null;
        });

        return completableFuture;
    }
    
    //test function
    @Test
    void testFuture() throws ExecutionException, InterruptedException {
        String code = "j=getIntAsync()\ni=getIntAsync()\nz=i+j\nreturn z";
        Map<Integer, Object> treeMap = new HashMap<Integer, Object>();
        DemoFunc eval = new DemoFunc();
        long start = System.currentTimeMillis();
        var val = eval.eval(getTree(code), new HashMap<String, Value>());
        long end = System.currentTimeMillis();
        assert(end-start>500);
        assert (val.equals(4));
    }

    @Test
    void testFutureAsync() throws ExecutionException, InterruptedException {
        String code = "j=getIntAsync()+getIntAsync()+getIntAsync()\nreturn j";
        Map<Integer, Object> treeMap = new HashMap<Integer, Object>();
        DemoFunc eval = new DemoFunc();
        var val = eval.evalAsync(getTree(code), new HashMap<String, Value>());
        assert(val.isFuture());
        assert (val.asFuture().get().equals(6));
    }        

ScriQ Grammar

ScriQ is a tiny variant of Python, support the following statement:

= # assignment
+,-,*,/,%, ** # arithmetic operations
and, or, not # boolean operators
if i: statments elif: statements else: statements
while i: statements
break # as last statement in while statements
return i # the value returned to ScriQ evaluator

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Publish

mvn clean deploy -P release