Files
paradigms/javascript/jstest/prefix/ParserTester.java
2026-04-13 20:12:01 +03:00

88 lines
3.6 KiB
Java

package jstest.prefix;
import base.Functional;
import base.Selector;
import common.expression.Dialect;
import common.expression.ExprTester;
import common.expression.Language;
import common.expression.LanguageBuilder;
import jstest.object.ObjectTester;
import java.util.stream.IntStream;
/**
* Tester for
* <a href="https://www.kgeorgiy.info/courses/paradigms/homeworks.html#js-expression-parsing">JavaScript Expression Parsing</a>
* homework of <a href="https://www.kgeorgiy.info/courses/paradigms">Programming Paradigms</a> course.
*
* @author Georgiy Korneev (kgeorgiy@kgeorgiy.info)
*/
public final class ParserTester {
public static final Dialect PREFIX = new Dialect("%s", "%s", "({op} {args})", " ");
private ParserTester() {
}
public static Selector.Composite<LanguageBuilder> selector(
final Class<?> owner,
final String toString,
final String parse,
final Dialect unparsed,
final String... parsingTests
) {
assert parsingTests.length % 2 == 0;
return LanguageBuilder.selector(owner, mode -> true, (builder, counter) -> {
final String insertions = builder.variant().hasVarargs() ? "abc()+*/@ABC" : "xyz()+*/@ABC";
final Language language = builder.language(ObjectTester.OBJECT, unparsed);
final ExprTester<Object> tester = ObjectTester.tester(
counter,
language,
toString,
parse,
(input, expr, random, build) -> build.add(removeSpaces(input)),
corrupt(insertions)
);
tester.addStage(() -> Functional.forEachPair(
parsingTests,
(input, context) -> printParsingError(tester, input, context)
));
return tester;
}, "", "easy", "hard");
}
private static String removeSpaces(final String expression) {
return expression.replace(" (", "(").replace(") ", ")");
}
private static void printParsingError(final ExprTester<?> test, final String description, final String input) {
final String message = new ExprTester.BadInput(input, "", "").assertError(test::parse);
final int index = message.lastIndexOf("in <eval>");
System.err.format("%-15s | %-25s: %s%n", input, description, message.substring(0, index > 0 ? index : message.length()));
}
private static ExprTester.Generator<ExprTester.BadInput> corrupt(final String insertions) {
return (input, expr, random, builder) -> IntStream.range(0, 1 + Math.min(10, 200 / input.length())).boxed()
.forEach(i -> {
final int index = random.nextInt(input.length());
final char c = input.charAt(index);
if (!Character.isDigit(c) && !Character.isWhitespace(c) && "-hxyz".indexOf(c) == -1) {
builder.add(new ExprTester.BadInput(
input.substring(0, index),
"<SYMBOL REMOVED>",
input.substring(index + 1)
));
}
final char newC = insertions.charAt(random.nextInt(insertions.length()));
if (!Character.isDigit(c) && c != '-') {
builder.add(new ExprTester.BadInput(
input.substring(0, index),
"<SYMBOL INSERTED -->",
newC + input.substring(index)
));
}
});
}
}