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package org.zwobble.couscous.interpreter;
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;
import org.zwobble.couscous.values.TypeReference;
import static java.util.stream.Collectors.toMap;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.Setter;
import lombok.val;
public class Environment {
private final Project project;
private final Map<Integer, VariableEntry> stackFrame;
public Environment(Project project, Map<VariableNode, Optional<InterpreterValue>> stackFrame) {
this.project = project;
this.stackFrame = stackFrame.entrySet()
.stream()
.collect(toMap(
entry -> entry.getKey().getId(),
entry -> VariableEntry.of(entry.getKey().getType(), entry.getValue())));
}
public InterpreterValue get(int variableId) {
checkVariableIsInScope(variableId);
val entry = stackFrame.get(variableId);
return entry.getValue().orElseThrow(() -> new UnboundVariable(variableId));
}
public void put(int variableId, InterpreterValue value) {
checkVariableIsInScope(variableId);
checkVariableType(variableId, value);
stackFrame.get(variableId).setValue(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<VariableNode, Optional<InterpreterValue>> stackFrame) {
return new Environment(project, stackFrame);
}
private void checkVariableIsInScope(int variableId) {
if (!stackFrame.containsKey(variableId)) {
throw new VariableNotInScope(variableId);
}
}
private void checkVariableType(int variableId, InterpreterValue value) {
val variableType = stackFrame.get(variableId).getType();
val valueType = value.getType().getReference();
if (!variableType.equals(valueType)) {
throw new UnexpectedValueType(variableType, valueType);
}
}
@AllArgsConstructor(staticName="of")
@Getter
@Setter
private static class VariableEntry {
private final TypeReference type;
private Optional<InterpreterValue> value;
}
}
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