Display expected tokens on ParseError

This commit is contained in:
Arne Keller 2021-03-11 14:30:37 +01:00
parent 9767002ad1
commit d8b547177a
8 changed files with 131 additions and 43 deletions

View File

@ -69,7 +69,7 @@ public class LambdaParser {
TokenType current = token.getType();
Optional<ParseError> error = nextToken();
if (current != type) {
return Optional.of(ParseError.UNEXPECTED_TOKEN.withToken(lastToken));
return Optional.of(ParseError.UNEXPECTED_TOKEN.withToken(lastToken).expectedType(type));
}
return error;
}
@ -84,11 +84,15 @@ public class LambdaParser {
if (t.isError()) {
return t;
}
Token last = token;
Optional<ParseError> next = expect(TokenType.EOF);
if (next.isEmpty()) {
return t;
}
return new Result<>(null, next.get());
return new Result<>(null,
(last.getType() == TokenType.EOF ? ParseError.TOO_FEW_TOKENS : ParseError.UNEXPECTED_TOKEN)
.withToken(last)
.expectedTypes(ATOM_START_TOKENS));
}
/**

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@ -1,7 +1,11 @@
package edu.kit.typicalc.model.parser;
import java.util.Collection;
import java.util.List;
import java.util.Optional;
/**
* Errors that can occur when parsing a lambda term.
* Errors that can occur when parsing a lambda term or type assumption.
*
* @see LambdaLexer
* @see LambdaParser
@ -23,7 +27,8 @@ public enum ParseError {
*/
UNEXPECTED_CHARACTER;
private Token cause = new Token(Token.TokenType.EOF, "", -1);
private Optional<Token> cause = Optional.empty();
private Optional<Collection<Token.TokenType>> needed = Optional.empty();
private char wrongChar = '\0';
private int position = -1;
@ -34,7 +39,29 @@ public enum ParseError {
* @return this object
*/
public ParseError withToken(Token cause) {
this.cause = cause;
this.cause = Optional.of(cause);
return this;
}
/**
* Attach an expected token type to this error.
*
* @param needed the required token type
* @return this object
*/
public ParseError expectedType(Token.TokenType needed) {
this.needed = Optional.of(List.of(needed));
return this;
}
/**
* Attach expected token types to this error.
*
* @param needed the possible token types
* @return this object
*/
public ParseError expectedTypes(Collection<Token.TokenType> needed) {
this.needed = Optional.of(needed);
return this;
}
@ -52,16 +79,29 @@ public enum ParseError {
}
/**
* @return the token associated with this error, or null if none
* @return the token associated with this error
*/
public Token getCause() {
public Optional<Token> getCause() {
return cause;
}
/**
* @return the expected/possible token(s) if this error is UNEXPECTED_TOKEN
*/
public Optional<Collection<Token.TokenType>> getExpected() {
return needed;
}
/**
* @return the wrong character if this error is UNEXPECTED_CHARACTER ('\0' otherwise)
*/
public char getWrongCharacter() {
return wrongChar;
}
/**
* @return the character position if this error is UNEXPECTED_CHARACTER
*/
public int getPosition() {
return position;
}

View File

@ -12,7 +12,7 @@ public class Token {
* VARIABLE and NUMBER have a regular expression associated with them.
* EOF is a special token to indicate that the end of file is reached.
*/
enum TokenType {
public enum TokenType {
LAMBDA, // λ or a backslash
VARIABLE, // [a-z][a-zA-Z0-9]* except "let" or "in" or constants
LET, // let
@ -25,7 +25,7 @@ public class Token {
DOT, // .
EQUALS, // =
ARROW, // ->
EOF // pseudo token if end of file is reached
EOF // pseudo token if end of input is reached
}
/**

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@ -38,16 +38,22 @@ public class TypicalcI18NProvider implements I18NProvider {
public String getTranslation(String key, Locale locale, Object... params) {
ResourceBundle bundle = ResourceBundle.getBundle(LANGUAGE_BUNDLE_PREFIX, locale);
String result;
if (bundle.containsKey(key)) {
return bundle.getString(key);
result = bundle.getString(key);
} else {
try {
return this.generalBundle.getString(key);
result = this.generalBundle.getString(key);
} catch (MissingResourceException exception) {
// this is only the case for untranslated texts
return "?[" + key + "]?";
}
}
// replace placeholders {0} ...
for (int i = 0; i < params.length; i++) {
result = result.replace(String.format("{%d}", i), params[i].toString());
}
return result;
}
}

View File

@ -2,7 +2,6 @@ package edu.kit.typicalc.view.content.errorcontent;
import com.vaadin.flow.component.Component;
import com.vaadin.flow.component.dependency.CssImport;
import com.vaadin.flow.component.details.Details;
import com.vaadin.flow.component.html.Div;
import com.vaadin.flow.component.html.H3;
import com.vaadin.flow.component.html.Paragraph;
@ -11,8 +10,12 @@ import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.vaadin.flow.i18n.LocaleChangeEvent;
import com.vaadin.flow.i18n.LocaleChangeObserver;
import edu.kit.typicalc.model.parser.ParseError;
import edu.kit.typicalc.model.parser.Token;
import edu.kit.typicalc.view.main.InfoContent;
import java.util.Collection;
import java.util.Optional;
@CssImport("./styles/view/error-view.css")
public class ErrorView extends VerticalLayout implements LocaleChangeObserver {
private static final long serialVersionUID = 239587L;
@ -21,8 +24,6 @@ public class ErrorView extends VerticalLayout implements LocaleChangeObserver {
private static final String ADDITIONAL_INFO_ID = "errorAdditionalInfo";
private static final String ERROR_SUMMARY_ID = "errorSummary";
private static final int NO_ADDITIONAL_INFO = -1;
private final H3 heading;
private final Div errorMessage;
private final ParseError error;
@ -44,26 +45,48 @@ public class ErrorView extends VerticalLayout implements LocaleChangeObserver {
Paragraph summary = new Paragraph(getTranslation("root." + error.toString()));
summary.setId(ERROR_SUMMARY_ID);
if (error == ParseError.TOO_FEW_TOKENS) {
additionalInformation.add(new Span(getTranslation("root.tooFewTokensHelp")));
} else if (error == ParseError.UNEXPECTED_CHARACTER) {
char c = error.getWrongCharacter();
if (c != '\0') {
additionalInformation.add(new Span(getTranslation("root.wrongCharacter") + c));
additionalInformation.add(new Span(getTranslation("root.position") + error.getPosition()));
} else {
return summary;
}
} else {
if (error.getCause().getPos() == NO_ADDITIONAL_INFO) {
return summary;
} else {
additionalInformation.add(new Span(getTranslation("root.wrongCharacter") + error.getCause().getText()));
additionalInformation.add(new Span(getTranslation("root.position") + error.getCause().getPos()));
}
switch (error) {
case TOO_FEW_TOKENS:
additionalInformation.add(new Span(getTranslation("root.tooFewTokensHelp")));
break;
case UNEXPECTED_TOKEN:
Optional<Token> cause = error.getCause();
if (cause.isPresent()) {
additionalInformation.add(new Span(getTranslation("root.wrongCharacter") + cause.get().getText()));
additionalInformation.add(new Span(getTranslation("root.position") + cause.get().getPos()));
}
break;
case UNEXPECTED_CHARACTER:
char c = error.getWrongCharacter();
if (c != '\0') {
additionalInformation.add(new Span(getTranslation("root.wrongCharacter") + c));
additionalInformation.add(new Span(getTranslation("root.position") + error.getPosition()));
} else {
return summary;
}
break;
default:
throw new IllegalStateException(); // delete when updating to Java 12+
}
return new Details(summary, additionalInformation);
// add expected tokens, if available
Optional<Collection<Token.TokenType>> expected = error.getExpected();
if (expected.isPresent()) {
Collection<Token.TokenType> possible = expected.get();
StringBuilder sb = new StringBuilder();
for (Token.TokenType t : possible) {
if (sb.length() > 0) {
sb.append(' ');
sb.append(getTranslation("root.or"));
sb.append(' ');
}
sb.append(getTranslation("tokentype." + t));
}
additionalInformation.add(new Span(
getTranslation("error.expectedToken", sb.toString())));
}
return new Div(summary, additionalInformation);
}
@Override

View File

@ -100,6 +100,21 @@ root.UNEXPECTED_CHARACTER=Die Eingabe enthält ein Zeichen, welches an dieser St
error.heading=Syntaktisch falsche Eingabe!
root.wrongCharacter=Falsches Zeichen: \u0020
root.position=An Position: \u0020
error.expectedToken=Erwartet: {0}
tokentype.LAMBDA=λ
tokentype.VARIABLE=Variable
tokentype.LET=let
tokentype.IN=in
tokentype.TRUE=true
tokentype.FALSE=false
tokentype.NUMBER=Zahl
tokentype.LEFT_PARENTHESIS=(
tokentype.RIGHT_PARENTHESIS=)
tokentype.DOT=.
tokentype.EQUALS==
tokentype.ARROW=->
tokentype.EOF=Ende der Eingabe
root.or=oder
root.slideExp=Typicalc ist eine Anwendung zur Visualisierung von Typinferenz. In der folgenden Slideshow wird ein \
Beispielszenario mit den wichtigsten Funktionen der Website vorgeführt. Das relevante Bedienelement ist jeweils mit \
einem roten Rahmen hervorgehoben. Zwischen einzelnen Slides kann mithilfe der Knöpfe am unteren Ende der Seite \

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@ -98,7 +98,7 @@ class LambdaParserTest {
parser = new LambdaParser("x)");
ParseError error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_TOKEN, error);
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 1), error.getCause());
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 1), error.getCause().get());
parser = new LambdaParser("??");
assertEquals(ParseError.UNEXPECTED_CHARACTER, parser.parse().unwrapError());
parser = new LambdaParser("");
@ -110,39 +110,39 @@ class LambdaParserTest {
parser = new LambdaParser("x 123333333333333");
error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_CHARACTER, error);
assertEquals(new Token(TokenType.NUMBER, "123333333333333", 2), error.getCause());
assertEquals(new Token(TokenType.NUMBER, "123333333333333", 2), error.getCause().get());
parser = new LambdaParser("λ)");
error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_TOKEN, error);
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 1), error.getCause());
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 1), error.getCause().get());
parser = new LambdaParser("λx=");
error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_TOKEN, error);
assertEquals(new Token(TokenType.EQUALS, "=", 2), error.getCause());
assertEquals(new Token(TokenType.EQUALS, "=", 2), error.getCause().get());
parser = new LambdaParser("λx..");
error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_TOKEN, error);
assertEquals(new Token(TokenType.DOT, ".", 3), error.getCause());
assertEquals(new Token(TokenType.DOT, ".", 3), error.getCause().get());
parser = new LambdaParser("let ) =");
error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_TOKEN, error);
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 4), error.getCause());
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 4), error.getCause().get());
parser = new LambdaParser("let x .");
error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_TOKEN, error);
assertEquals(new Token(TokenType.DOT, ".", 6), error.getCause());
assertEquals(new Token(TokenType.DOT, ".", 6), error.getCause().get());
parser = new LambdaParser("let x = )");
error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_TOKEN, error);
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 8), error.getCause());
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 8), error.getCause().get());
parser = new LambdaParser("let x = y )");
error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_TOKEN, error);
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 10), error.getCause());
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 10), error.getCause().get());
parser = new LambdaParser("let x = y in )");
error = parser.parse().unwrapError();
assertEquals(ParseError.UNEXPECTED_TOKEN, error);
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 13), error.getCause());
assertEquals(new Token(TokenType.RIGHT_PARENTHESIS, ")", 13), error.getCause().get());
}
@Test

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@ -210,7 +210,7 @@ class TypeAssumptionParserTest {
Result<Map<VarTerm, TypeAbstraction>, ParseError> type = parser.parse(Map.of("type1", entry.getKey()));
assertTrue(type.isError());
assertEquals(entry.getValue(), type.unwrapError());
if (entry.getValue().getCause().getPos() != -1) {
if (entry.getValue().getCause().isPresent()) {
assertEquals(entry.getValue().getCause(), type.unwrapError().getCause());
}
}