christoph/lecture-compilers
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update actions, add nullable

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ChUrl
2020-12-11 17:29:18 +01:00
parent 2277f6b165
commit f54dc717e7
1 changed files with 32 additions and 23 deletions
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55
src/main/java/parser/grammar/Grammar.java
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@ -6,15 +6,13 @@ import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
import static parser.Actions.COMPACT;
import static parser.Actions.NULLABLE;
import static util.tools.Logger.log;
public class Grammar {
@ -25,18 +23,21 @@ public class Grammar {
private final String epsilonSymbol;
// Actions
private final Map<String, Set<String>> compact;
private final Set<String> compact;
private final Set<String> nullable;
private final Set<GrammarRule> rules;
public Grammar(Set<String> terminals, Set<String> nonterminals,
String startSymbol, String epsilonSymbol,
Map<String, Set<String>> compact, Set<GrammarRule> rules) {
Set<String> compact, Set<String> nullable,
Set<GrammarRule> rules) {
this.terminals = terminals;
this.nonterminals = nonterminals;
this.startSymbol = startSymbol;
this.epsilonSymbol = epsilonSymbol;
this.compact = compact;
this.nullable = nullable;
this.rules = rules;
}
@ -54,7 +55,8 @@ public class Grammar {
Set<String> terminals = new HashSet<>();
Set<String> nonterminals = new HashSet<>();
Map<String, Set<String>> compact = new HashMap<>();
Set<String> compact = new HashSet<>();
Set<String> nullable = new HashSet<>();
Set<GrammarRule> rules = new HashSet<>();
log("Parsing Grammar from File:");
@ -82,7 +84,6 @@ public class Grammar {
String leftside = split[0].trim();
String rightside = split[1].trim();
List<String> flagList = Collections.emptyList();
if (leftside.indexOf('[') >= 0) {
// Handle actions if they exist
@ -91,10 +92,12 @@ public class Grammar {
// Aus "S[C R]" wird flags = {"C", "R"} extrahiert
String[] flags = leftside.substring(open + 1, close).split(" ");
flagList = Arrays.stream(flags)
.map(String::trim)
.filter(flag -> !flag.isEmpty())
.collect(Collectors.toList());
List<String> flagList = Arrays.stream(flags)
.map(String::trim)
.filter(flag -> !flag.isEmpty())
.collect(Collectors.toList());
// Check for action validity
List<String> enumActions = Arrays.stream(Actions.values())
.map(action -> action.toString().toLowerCase())
.collect(Collectors.toList());
@ -106,24 +109,25 @@ public class Grammar {
// "S[C R]" wird zu "S"
leftside = leftside.substring(0, open).trim();
// Register action
if (flagList.contains(COMPACT.toString().toLowerCase())) {
compact.add(leftside.trim());
log("Registered compact: " + leftside.trim());
}
if (flagList.contains(NULLABLE.toString().toLowerCase())) {
nullable.add(leftside.trim());
log("Registered nullable: " + leftside.trim());
}
}
// "E T2 | epsilon" wird zu prods[0] = "E T2" und prods[1] = "epsilon"
String[] prods = rightside.split("\\|");
compact.put(leftside, new HashSet<>());
for (String prod : prods) {
GrammarRule rule = new GrammarRule(leftside, prod.split(" "));
rules.add(rule);
if (flagList.contains(COMPACT.toString().toLowerCase())) {
compact.get(leftside).add(prod.trim());
log("Registered compact: " + leftside + " -> " + prod.trim());
}
}
if (!flagList.isEmpty()) {
log("\n");
}
}
}
@ -133,7 +137,8 @@ public class Grammar {
return new Grammar(terminals, nonterminals,
startSymbol, epsilonSymbol,
compact, rules);
compact, nullable,
rules);
} catch (Exception e) {
log("Die Grammatik kann nicht gelesen werden!");
log(path.toString());
@ -176,7 +181,11 @@ public class Grammar {
.collect(Collectors.toUnmodifiableSet());
}
public boolean hasCompact(String leftside, String rightside) {
return this.compact != null && this.compact.get(leftside).contains(rightside);
public boolean hasCompact(String leftside) {
return this.compact != null && this.compact.contains(leftside);
}
public boolean hasNullable(String leftside) {
return this.nullable != null && this.nullable.contains(leftside);
}
}