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mirror of https://github.com/DanilaFe/abacus synced 2026-01-26 16:45:21 +00:00

Format code.

This commit is contained in:
2017-07-30 21:11:32 -07:00
parent 122874b97a
commit 3ce74303ed
39 changed files with 695 additions and 561 deletions

View File

@@ -10,15 +10,111 @@ import java.util.*;
/**
* A lexer that can generate tokens of a given type given a list of regular expressions
* to operate on.
*
* @param <T> the type used to identify which match belongs to which pattern.
*/
public class Lexer<T> {
/**
* The registered patterns.
*/
private Map<PatternEntry<T>, Pattern<T>> patterns;
/**
* Creates a new lexer with no registered patterns.
*/
public Lexer() {
patterns = new HashMap<>();
}
/**
* Registers a single pattern.
*
* @param pattern the pattern regex
* @param id the ID by which to identify the pattern.
*/
public void register(String pattern, T id) {
Pattern<T> compiledPattern = new Pattern<>(pattern, id);
if (compiledPattern.getHead() != null) patterns.put(new PatternEntry<>(pattern, id), compiledPattern);
}
/**
* Unregisters a pattern.
*
* @param pattern the pattern to unregister
* @param id the ID by which to identify the pattern.
*/
public void unregister(String pattern, T id) {
patterns.remove(new PatternEntry<>(pattern, id));
}
/**
* Reads one token from the given string.
*
* @param from the string to read from
* @param startAt the index to start at
* @param compare the comparator used to sort tokens by their ID.
* @return the best match.
*/
public Match<T> lexOne(String from, int startAt, Comparator<T> compare) {
ArrayList<Match<T>> matches = new ArrayList<>();
HashSet<PatternNode<T>> currentSet = new HashSet<>();
HashSet<PatternNode<T>> futureSet = new HashSet<>();
int index = startAt;
for (Pattern<T> pattern : patterns.values()) {
pattern.getHead().addInto(currentSet);
}
while (!currentSet.isEmpty()) {
for (PatternNode<T> node : currentSet) {
if (index < from.length() && node.matches(from.charAt(index))) {
node.addOutputsInto(futureSet);
} else if (node instanceof EndNode) {
matches.add(new Match<>(from.substring(startAt, index), ((EndNode<T>) node).getPatternId()));
}
}
HashSet<PatternNode<T>> tmp = currentSet;
currentSet = futureSet;
futureSet = tmp;
futureSet.clear();
index++;
}
matches.sort((a, b) -> compare.compare(a.getType(), b.getType()));
if (compare != null) {
matches.sort(Comparator.comparingInt(a -> a.getContent().length()));
}
return matches.isEmpty() ? null : matches.get(matches.size() - 1);
}
/**
* Reads all tokens from a string.
*
* @param from the string to start from.
* @param startAt the index to start at.
* @param compare the comparator used to sort matches by their IDs.
* @return the resulting list of matches, in order, or null on error.
*/
public List<Match<T>> lexAll(String from, int startAt, Comparator<T> compare) {
int index = startAt;
ArrayList<Match<T>> matches = new ArrayList<>();
Match<T> lastMatch = null;
while (index < from.length() && (lastMatch = lexOne(from, index, compare)) != null) {
int length = lastMatch.getContent().length();
if (length == 0) return null;
matches.add(lastMatch);
index += length;
}
if (lastMatch == null) return null;
return matches;
}
/**
* An entry that represents a pattern that has been registered with the lexer.
*
* @param <T> the type used to identify the pattern.
*/
private static class PatternEntry<T>{
private static class PatternEntry<T> {
/**
* The name of the entry.
*/
@@ -30,10 +126,11 @@ public class Lexer<T> {
/**
* Creates a new pattern entry with the given name and id.
*
* @param name the name of the pattern entry.
* @param id the id of the pattern entry.
* @param id the id of the pattern entry.
*/
public PatternEntry(String name, T id){
public PatternEntry(String name, T id) {
this.name = name;
this.id = id;
}
@@ -51,94 +148,4 @@ public class Lexer<T> {
}
}
/**
* The registered patterns.
*/
private Map<PatternEntry<T>, Pattern<T>> patterns;
/**
* Creates a new lexer with no registered patterns.
*/
public Lexer(){
patterns = new HashMap<>();
}
/**
* Registers a single pattern.
* @param pattern the pattern regex
* @param id the ID by which to identify the pattern.
*/
public void register(String pattern, T id){
Pattern<T> compiledPattern = new Pattern<>(pattern, id);
if(compiledPattern.getHead() != null) patterns.put(new PatternEntry<>(pattern, id), compiledPattern);
}
/**
* Unregisters a pattern.
* @param pattern the pattern to unregister
* @param id the ID by which to identify the pattern.
*/
public void unregister(String pattern, T id){
patterns.remove(new PatternEntry<>(pattern, id));
}
/**
* Reads one token from the given string.
* @param from the string to read from
* @param startAt the index to start at
* @param compare the comparator used to sort tokens by their ID.
* @return the best match.
*/
public Match<T> lexOne(String from, int startAt, Comparator<T> compare){
ArrayList<Match<T>> matches = new ArrayList<>();
HashSet<PatternNode<T>> currentSet = new HashSet<>();
HashSet<PatternNode<T>> futureSet = new HashSet<>();
int index = startAt;
for(Pattern<T> pattern : patterns.values()){
pattern.getHead().addInto(currentSet);
}
while(!currentSet.isEmpty()){
for(PatternNode<T> node : currentSet){
if(index < from.length() && node.matches(from.charAt(index))) {
node.addOutputsInto(futureSet);
} else if(node instanceof EndNode){
matches.add(new Match<>(from.substring(startAt, index), ((EndNode<T>) node).getPatternId()));
}
}
HashSet<PatternNode<T>> tmp = currentSet;
currentSet = futureSet;
futureSet = tmp;
futureSet.clear();
index++;
}
matches.sort((a, b) -> compare.compare(a.getType(), b.getType()));
if(compare != null) {
matches.sort(Comparator.comparingInt(a -> a.getContent().length()));
}
return matches.isEmpty() ? null : matches.get(matches.size() - 1);
}
/**
* Reads all tokens from a string.
* @param from the string to start from.
* @param startAt the index to start at.
* @param compare the comparator used to sort matches by their IDs.
* @return the resulting list of matches, in order, or null on error.
*/
public List<Match<T>> lexAll(String from, int startAt, Comparator<T> compare){
int index = startAt;
ArrayList<Match<T>> matches = new ArrayList<>();
Match<T> lastMatch = null;
while(index < from.length() && (lastMatch = lexOne(from, index, compare)) != null){
int length = lastMatch.getContent().length();
if(length == 0) return null;
matches.add(lastMatch);
index += length;
}
if(lastMatch == null) return null;
return matches;
}
}