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expression parser allows to omit the and operator

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This commit is contained in:
hneemann 2017-06-29 20:29:40 +02:00
parent c4066a1e8f
commit fd878a4f7b
2 changed files with 33 additions and 4 deletions
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16
src/main/java/de/neemann/digital/analyse/parser/Parser.java
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@ -83,11 +83,19 @@ public class Parser {
private Expression parseAnd() throws IOException, ParseException {
Expression ex = parseSimpleExp();
while (tokenizer.peek() == AND) {
tokenizer.consume();
ex = Operation.and(ex, parseSimpleExp());
while (true) {
if (tokenizer.peek() == AND) {
tokenizer.consume();
ex = Operation.and(ex, parseSimpleExp());
} else if (isSimpleEx(tokenizer.peek())) {
ex = Operation.and(ex, parseSimpleExp());
} else
return ex;
}
return ex;
}
private boolean isSimpleEx(Tokenizer.Token tok) {
return tok == NOT || tok == OPEN || tok == IDENT || tok == ONE || tok == ZERO;
}
private Expression parseSimpleExp() throws IOException, ParseException {

21
src/test/java/de/neemann/digital/analyse/parser/ParserTest.java
View File

@ -47,6 +47,7 @@ public class ParserTest extends TestCase {
assertTrue(createSingle("a∧b") instanceof Operation.And);
assertTrue(createSingle("a&b") instanceof Operation.And);
assertTrue(createSingle("a&&b") instanceof Operation.And);
assertTrue(createSingle("a b") instanceof Operation.And);
}
public void testParseParenthesis() throws Exception {
@ -100,6 +101,16 @@ public class ParserTest extends TestCase {
assertEquals(new Variable("B"), simplified);
}
public void testParseRegressionOmitAnd() throws Exception {
Expression e = createSingle("B(B+A)(B+C)(A+B+C)");
Expression simplified = QuineMcCluskey.simplify(e);
assertEquals(new Variable("B"), simplified);
e = createSingle("B (B+A) (B+C) (A+B+C)");
simplified = QuineMcCluskey.simplify(e);
assertEquals(new Variable("B"), simplified);
}
public void testParseRegression2() throws Exception {
Expression e = createSingle("(C ∨ B) ∧ (A ∨ C) ∧ (B ∨ ¬C) ∧ (C ∨ ¬A)");
Expression simplified = QuineMcCluskey.simplify(e);
@ -110,6 +121,16 @@ public class ParserTest extends TestCase {
assertEquals(new Variable("C"), expList.get(1));
}
public void testParseRegression2OmitAnd() throws Exception {
Expression e = createSingle("(C ∨ B) (A ∨ C) (B ∨ ¬C) (C ∨ ¬A)");
Expression simplified = QuineMcCluskey.simplify(e);
assertTrue(simplified instanceof Operation.And);
ArrayList<Expression> expList = ((Operation) simplified).getExpressions();
assertEquals(2, expList.size());
assertEquals(new Variable("B"), expList.get(0));
assertEquals(new Variable("C"), expList.get(1));
}
public void testParseException() throws Exception {
Parser p = new Parser("C+");
try {