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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
package org.zwobble.couscous.tests.interpreter;
import org.junit.Test;
import org.zwobble.couscous.MapBackedProject;
import org.zwobble.couscous.ast.Assignment;
import org.zwobble.couscous.ast.ClassNode;
import org.zwobble.couscous.ast.ExpressionStatementNode;
import org.zwobble.couscous.ast.FormalArgumentNode;
import org.zwobble.couscous.ast.LiteralNode;
import org.zwobble.couscous.ast.MethodNode;
import org.zwobble.couscous.ast.ReturnNode;
import org.zwobble.couscous.interpreter.Interpreter;
import org.zwobble.couscous.interpreter.UnboundVariable;
import org.zwobble.couscous.interpreter.UnexpectedValueType;
import org.zwobble.couscous.interpreter.VariableNotInScope;
import org.zwobble.couscous.interpreter.WrongNumberOfArguments;
import org.zwobble.couscous.values.ConcreteType;
import org.zwobble.couscous.values.IntegerValue;
import org.zwobble.couscous.values.InterpreterValue;
import org.zwobble.couscous.values.StringValue;
import com.google.common.collect.ImmutableMap;
import static java.util.Arrays.asList;
import static org.junit.Assert.assertEquals;
import static org.zwobble.couscous.ast.LiteralNode.literal;
import static org.zwobble.couscous.ast.LocalVariableDeclarationNode.localVariableDeclaration;
import static org.zwobble.couscous.ast.MethodNode.staticMethod;
import static org.zwobble.couscous.ast.VariableReferenceNode.reference;
import static org.zwobble.couscous.tests.util.ExtraAsserts.assertThrows;
import static org.zwobble.couscous.values.UnitValue.UNIT;
import lombok.val;
public class InterpreterTests {
@Test
public void methodWithNoStatementsReturnsUnit() {
val method = staticMethod("hello");
val result = runMethod(method);
assertEquals(UNIT, result);
}
@Test
public void canReturnLiteralValue() {
val method = staticMethod("hello")
.statement(new ReturnNode(LiteralNode.literal("hello, world!")));
val result = runMethod(method);
assertEquals(new StringValue("hello, world!"), result);
}
@Test
public void canPassValueToMethod() {
val arg = new FormalArgumentNode(42, StringValue.REF, "x");
val method = staticMethod("hello")
.argument(arg)
.statement(new ReturnNode(reference(arg)));
val result = runMethod(method, new StringValue("hello, world!"));
assertEquals(new StringValue("hello, world!"), result);
}
@Test
public void errorIfWrongNumberOfArgumentsArePassed() {
val method = staticMethod("hello");
val exception = assertThrows(WrongNumberOfArguments.class,
() -> runMethod(method, new StringValue("hello, world!")));
assertEquals(new WrongNumberOfArguments(0, 1), exception);
}
@Test
public void canReassignValueToArgument() {
val arg = new FormalArgumentNode(42, StringValue.REF, "x");
val method = staticMethod("hello")
.argument(arg)
.statement(new ExpressionStatementNode(new Assignment(reference(arg), LiteralNode.literal("[updated value]"))))
.statement(new ReturnNode(reference(arg)));
val result = runMethod(method, new StringValue("[initial value]"));
assertEquals(new StringValue("[updated value]"), result);
}
@Test
public void errorIfTryingToAssignValueOfWrongTypeToVariable() {
val arg = new FormalArgumentNode(42, StringValue.REF, "x");
val method = staticMethod("hello")
.argument(arg)
.statement(new ExpressionStatementNode(new Assignment(reference(arg), literal(0))));
val exception = assertThrows(UnexpectedValueType.class,
() -> runMethod(method, new StringValue("")));
assertEquals(new UnexpectedValueType(StringValue.REF, IntegerValue.REF), exception);
}
@Test
public void canDeclareVariable() {
val localVariableDeclaration = localVariableDeclaration(
42, StringValue.REF, "x", LiteralNode.literal("[initial value]"));
val method = staticMethod("hello")
.statement(localVariableDeclaration)
.statement(new ReturnNode(reference(localVariableDeclaration)));
val result = runMethod(method);
assertEquals(new StringValue("[initial value]"), result);
}
@Test
public void canDeclareVariableAndThenAssignValues() {
val localVariableDeclaration = localVariableDeclaration(
42, StringValue.REF, "x", LiteralNode.literal("[initial value]"));
val method = staticMethod("hello")
.statement(localVariableDeclaration)
.statement(new ExpressionStatementNode(new Assignment(reference(localVariableDeclaration), LiteralNode.literal("[updated value]"))))
.statement(new ReturnNode(reference(localVariableDeclaration)));
val result = runMethod(method);
assertEquals(new StringValue("[updated value]"), result);
}
@Test
public void errorIfTryingToAssignToVariableNotInScope() {
val localVariableDeclaration = localVariableDeclaration(
42, StringValue.REF, "x", literal(""));
val method = staticMethod("hello")
.statement(new ExpressionStatementNode(new Assignment(reference(localVariableDeclaration), LiteralNode.literal("[updated value]"))));
val exception = assertThrows(VariableNotInScope.class,
() -> runMethod(method));
assertEquals(new VariableNotInScope(42), exception);
}
@Test
public void errorIfTryingToGetValueOfVariableNotInScope() {
val localVariableDeclaration = localVariableDeclaration(
42, StringValue.REF, "x", literal(""));
val method = staticMethod("hello")
.statement(new ReturnNode(reference(localVariableDeclaration)));
val exception = assertThrows(VariableNotInScope.class,
() -> runMethod(method));
assertEquals(new VariableNotInScope(42), exception);
}
@Test
public void errorIfTryingToGetValueOfUnboundVariable() {
val localVariableDeclaration = localVariableDeclaration(
42, StringValue.REF, "x", literal(""));
val method = staticMethod("hello")
.statement(new ReturnNode(reference(localVariableDeclaration)))
.statement(localVariableDeclaration);
val exception = assertThrows(UnboundVariable.class,
() -> runMethod(method));
assertEquals(new UnboundVariable(42), exception);
}
private InterpreterValue runMethod(MethodNode.MethodNodeBuilder methodBuilder, InterpreterValue... arguments) {
val method = methodBuilder.build();
val className = "com.example.Program";
val classNode = ClassNode.builder(className)
.method(method)
.build();
val interpreter = new Interpreter(new MapBackedProject(ImmutableMap.of(
className, ConcreteType.fromNode(classNode))));
return interpreter.run(className, method.getName(), asList(arguments));
}
}
|
