src/main/java/org/zwobble/couscous/interpreter/Environment.java


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48

package org.zwobble.couscous.interpreter;

import java.util.HashMap;
import java.util.Map;
import java.util.Optional;

import org.zwobble.couscous.Project;
import org.zwobble.couscous.ast.VariableNode;
import org.zwobble.couscous.values.ConcreteType;
import org.zwobble.couscous.values.InterpreterValue;

public class Environment {
    private final Map<Integer, Optional<InterpreterValue>> stackFrame;
    private final Project project;

    public Environment(Project project, Map<Integer, Optional<InterpreterValue>> stackFrame) {
        this.project = project;
        this.stackFrame = new HashMap<>(stackFrame);
    }

    public InterpreterValue get(int referentId) {
        return stackFrame.get(referentId).get();
    }

    public void put(int variableId, InterpreterValue value) {
        checkVariable(variableId);
        stackFrame.put(variableId, Optional.of(value));
    }

    public void put(VariableNode variable, InterpreterValue value) {
        put(variable.getId(), value);
    }

    public ConcreteType<?> findClass(String className) {
        // TODO: handle missing classes
        return project.findClass(className);
    }

    public Environment withStackFrame(Map<Integer, Optional<InterpreterValue>> stackFrame) {
        return new Environment(project, stackFrame);
    }

    private void checkVariable(int variableId) {
        if (!stackFrame.containsKey(variableId)) {
            throw new VariableNotInScope(variableId);
        }
    }
}