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
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
package org.zwobble.couscous.interpreter;
import org.zwobble.couscous.ast.*;
import org.zwobble.couscous.ast.visitors.DynamicNodeMapper;
import org.zwobble.couscous.interpreter.values.InterpreterValue;
import org.zwobble.couscous.interpreter.values.UnitInterpreterValue;
import java.util.List;
import java.util.Optional;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.stream.Stream;
import static org.zwobble.couscous.ast.structure.NodeStructure.descendantNodesAndSelf;
import static org.zwobble.couscous.interpreter.Evaluator.eval;
import static org.zwobble.couscous.interpreter.Evaluator.evalCondition;
import static org.zwobble.couscous.util.ExtraIterables.forEach;
public class Executor {
public static InterpreterValue callMethod(
Environment environment,
MethodNode method,
Optional<InterpreterValue> thisValue,
Arguments actualArguments)
{
List<StatementNode> body = method.getBody().orElseThrow(() -> new RuntimeException("Cannot call abstract method"));
return callMethod(environment, method.getArguments(), body, thisValue, actualArguments);
}
public static InterpreterValue callConstructor(
Environment environment,
ConstructorNode constructor,
InterpreterValue thisValue,
Arguments actualArguments)
{
return callMethod(environment, constructor.getArguments(), constructor.getBody(), Optional.of(thisValue), actualArguments);
}
private static InterpreterValue callMethod(
Environment environment,
List<FormalArgumentNode> formalArguments,
List<StatementNode> statements,
Optional<InterpreterValue> thisValue,
Arguments actualArguments)
{
Environment innerEnvironment = buildEnvironment(environment, formalArguments, statements, thisValue, actualArguments);
return exec(innerEnvironment, statements)
.orElse(UnitInterpreterValue.UNIT);
}
private static Environment buildEnvironment(
Environment environment,
List<FormalArgumentNode> formalArguments,
List<StatementNode> statements,
Optional<InterpreterValue> thisValue,
Arguments arguments)
{
StackFrameBuilder stackFrame = new StackFrameBuilder();
forEach(formalArguments, arguments.getValues(), stackFrame::declare);
findDeclarations(statements).forEach(declaration -> stackFrame.declare(declaration));
return environment.withStackFrame(thisValue, stackFrame.build());
}
private static Stream<VariableNode> findDeclarations(List<StatementNode> body) {
return body.stream()
.flatMap(statement -> descendantNodesAndSelf(statement, node -> node instanceof StatementNode))
.flatMap(FindDirectDeclarations.VISITOR);
}
public static class FindDirectDeclarations {
private static final Function<Node, Stream<VariableNode>> VISITOR =
DynamicNodeMapper.instantiate(new FindDirectDeclarations(), "visit");
public Stream<VariableNode> visit(Node node) {
return Stream.empty();
}
public Stream<VariableNode> visit(LocalVariableDeclarationNode localVariableDeclaration) {
return Stream.of(localVariableDeclaration);
}
}
public static Optional<InterpreterValue> exec(Environment environment, Iterable<StatementNode> statements) {
for (StatementNode statement : statements) {
Optional<InterpreterValue> result = exec(environment, statement);
if (result.isPresent()) {
return result;
}
}
return Optional.empty();
}
public static Optional<InterpreterValue> exec(Environment environment, StatementNode statement) {
return EXEC.apply(statement, new Executor(environment));
}
private static final BiFunction<Node, Executor, Optional<InterpreterValue>> EXEC = DynamicNodeMapper.visitor(Executor.class, "visit");
private final Environment environment;
private Executor(Environment environment) {
this.environment = environment;
}
public Optional<InterpreterValue> visit(ReturnNode returnNode) {
return Optional.of(eval(environment, returnNode.getValue()));
}
public Optional<InterpreterValue> visit(ExpressionStatementNode expressionStatement) {
eval(environment, expressionStatement.getExpression());
return Optional.empty();
}
public Optional<InterpreterValue> visit(LocalVariableDeclarationNode localVariableDeclaration) {
final org.zwobble.couscous.interpreter.values.InterpreterValue value = eval(environment, localVariableDeclaration.getInitialValue());
environment.put(localVariableDeclaration, value);
return Optional.empty();
}
public Optional<InterpreterValue> visit(IfStatementNode ifStatement) {
List<StatementNode> body = evalCondition(environment, ifStatement.getCondition())
? ifStatement.getTrueBranch()
: ifStatement.getFalseBranch();
return exec(body);
}
public Optional<InterpreterValue> visit(WhileNode whileLoop) {
while (evalCondition(environment, whileLoop.getCondition())) {
Optional<InterpreterValue> result = exec(whileLoop.getBody());
if (result.isPresent()) {
return result;
}
}
return Optional.empty();
}
public Optional<InterpreterValue> visit(StatementBlockNode block) {
return exec(block.getStatements());
}
private Optional<InterpreterValue> exec(List<StatementNode> statements) {
for (StatementNode statement : statements) {
Optional<InterpreterValue> result = exec(environment, statement);
if (result.isPresent()) {
return result;
}
}
return Optional.empty();
}
}
|
