mirror of https://github.com/DanilaFe/abacus
Implement a tentative pattern class that can be compiled from a string.
This commit is contained in:
parent
2374c167a4
commit
6200381016
|
|
@ -0,0 +1,162 @@
|
|||
package org.nwapw.abacus.lexing.pattern;
|
||||
|
||||
import java.util.Collection;
|
||||
import java.util.HashMap;
|
||||
import java.util.Stack;
|
||||
import java.util.function.Function;
|
||||
|
||||
public class Pattern<T> {
|
||||
|
||||
private T id;
|
||||
private PatternNode<T> head;
|
||||
private String source;
|
||||
private int index;
|
||||
|
||||
private HashMap<Character, Function<PatternChain<T>, PatternChain<T>>> operations =
|
||||
new HashMap<Character, Function<PatternChain<T>, PatternChain<T>>>() {{
|
||||
put('+', Pattern.this::transformPlus);
|
||||
put('*', Pattern.this::transformStar);
|
||||
put('?', Pattern.this::transformQuestion);
|
||||
}};
|
||||
|
||||
private PatternChain<T> transformPlus(PatternChain<T> chain){
|
||||
chain.tail.outputStates.add(chain.head);
|
||||
return chain;
|
||||
}
|
||||
|
||||
private PatternChain<T> transformStar(PatternChain<T> chain){
|
||||
LinkNode<T> newTail = new LinkNode<>();
|
||||
LinkNode<T> newHead = new LinkNode<>();
|
||||
newHead.outputStates.add(chain.head);
|
||||
newHead.outputStates.add(newTail);
|
||||
chain.tail.outputStates.add(newTail);
|
||||
newTail.outputStates.add(newHead);
|
||||
chain.head = newHead;
|
||||
chain.tail = newTail;
|
||||
return chain;
|
||||
}
|
||||
|
||||
private PatternChain<T> transformQuestion(PatternChain<T> chain){
|
||||
LinkNode<T> newTail = new LinkNode<>();
|
||||
LinkNode<T> newHead = new LinkNode<>();
|
||||
newHead.outputStates.add(chain.head);
|
||||
newHead.outputStates.add(newTail);
|
||||
chain.tail.outputStates.add(newTail);
|
||||
chain.head = newHead;
|
||||
chain.tail = newTail;
|
||||
return chain;
|
||||
}
|
||||
|
||||
private PatternChain<T> combineChains(Collection<PatternChain<T>> collection){
|
||||
LinkNode<T> head = new LinkNode<>();
|
||||
LinkNode<T> tail = new LinkNode<>();
|
||||
PatternChain<T> newChain = new PatternChain<>(head, tail);
|
||||
for(PatternChain<T> chain : collection){
|
||||
head.outputStates.add(chain.head);
|
||||
chain.tail.outputStates.add(tail);
|
||||
}
|
||||
return newChain;
|
||||
}
|
||||
|
||||
private PatternChain<T> parseValue(){
|
||||
if(index >= source.length()) return null;
|
||||
if(source.charAt(index) == '\\'){
|
||||
if(++index >= source.length()) return null;
|
||||
}
|
||||
return new PatternChain<>(new ValueNode<>(source.charAt(index++)));
|
||||
}
|
||||
|
||||
private PatternChain<T> parseOr(){
|
||||
Stack<PatternChain<T>> orStack = new Stack<>();
|
||||
while(index < source.length() && source.charAt(index) != ']'){
|
||||
if(source.charAt(index) == '-'){
|
||||
index++;
|
||||
if(orStack.empty() || orStack.peek().tail.range() == '\0') return null;
|
||||
PatternChain<T> bottomRange = orStack.pop();
|
||||
PatternChain<T> topRange = parseValue();
|
||||
if(topRange == null || topRange.tail.range() == '\0') return null;
|
||||
|
||||
orStack.push(new PatternChain<>(new RangeNode<>(bottomRange.tail.range(), topRange.tail.range())));
|
||||
} else {
|
||||
PatternChain<T> newChain = parseValue();
|
||||
if(newChain == null) return null;
|
||||
orStack.push(newChain);
|
||||
}
|
||||
index++;
|
||||
}
|
||||
if(index >= source.length()) return null;
|
||||
return combineChains(orStack);
|
||||
}
|
||||
|
||||
private PatternChain<T> parseSegment(boolean isSubsegment){
|
||||
if(index >= source.length() || ((source.charAt(index) != '(') && isSubsegment)) return null;
|
||||
if(isSubsegment) index++;
|
||||
|
||||
Stack<PatternChain<T>> orChain = new Stack<>();
|
||||
PatternChain<T> fullChain = new PatternChain<>();
|
||||
PatternChain<T> currentChain = null;
|
||||
while (index < source.length() && source.charAt(index) != ')'){
|
||||
char currentChar = source.charAt(index);
|
||||
if(operations.containsKey(currentChar)){
|
||||
if(currentChain == null) return null;
|
||||
|
||||
currentChain = operations.get(currentChar).apply(currentChain);
|
||||
fullChain.append(currentChain);
|
||||
currentChain = null;
|
||||
index++;
|
||||
} else if(currentChar == '|'){
|
||||
if(currentChain == null) return null;
|
||||
|
||||
fullChain.append(currentChain);
|
||||
orChain.push(fullChain);
|
||||
currentChain = null;
|
||||
fullChain = new PatternChain<>();
|
||||
} else if(currentChar == '('){
|
||||
if(currentChain != null) {
|
||||
fullChain.append(currentChain);
|
||||
}
|
||||
|
||||
currentChain = parseSegment(true);
|
||||
if(currentChain == null) return null;
|
||||
} else if(currentChar == '['){
|
||||
if(currentChain != null){
|
||||
fullChain.append(currentChain);
|
||||
}
|
||||
currentChain = parseOr();
|
||||
if(currentChain == null) return null;
|
||||
} else {
|
||||
if(currentChain != null){
|
||||
fullChain.append(currentChain);
|
||||
}
|
||||
currentChain = parseValue();
|
||||
if(currentChain == null) return null;
|
||||
}
|
||||
}
|
||||
|
||||
if(!(!isSubsegment || (index < source.length() && source.charAt(index) == ')'))) return null;
|
||||
if(isSubsegment) index++;
|
||||
|
||||
if(currentChain != null) fullChain.append(currentChain);
|
||||
if(!orChain.empty()){
|
||||
orChain.push(fullChain);
|
||||
fullChain = combineChains(orChain);
|
||||
}
|
||||
|
||||
return fullChain;
|
||||
}
|
||||
|
||||
public Pattern(String from, T id){
|
||||
this.id = id;
|
||||
index = 0;
|
||||
source = from;
|
||||
|
||||
PatternChain<T> chain = parseSegment(false);
|
||||
if(chain == null) {
|
||||
head = null;
|
||||
} else {
|
||||
chain.append(new EndNode<>(id));
|
||||
head = chain.head;
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
|
|
@ -0,0 +1,40 @@
|
|||
package org.nwapw.abacus.lexing.pattern;
|
||||
|
||||
public class PatternChain<T> {
|
||||
|
||||
public PatternNode<T> head;
|
||||
public PatternNode<T> tail;
|
||||
|
||||
public PatternChain(PatternNode<T> head, PatternNode<T> tail){
|
||||
this.head = head;
|
||||
this.tail = tail;
|
||||
}
|
||||
|
||||
public PatternChain(PatternNode<T> node){
|
||||
this(node, node);
|
||||
}
|
||||
|
||||
public PatternChain(){
|
||||
this(null);
|
||||
}
|
||||
|
||||
public void append(PatternChain<T> other){
|
||||
if(other.head == null || tail == null) {
|
||||
this.head = other.head;
|
||||
this.tail = other.tail;
|
||||
} else {
|
||||
tail.outputStates.add(other.head);
|
||||
tail = other.tail;
|
||||
}
|
||||
}
|
||||
|
||||
public void append(PatternNode<T> node){
|
||||
if(tail == null){
|
||||
head = tail = node;
|
||||
} else {
|
||||
tail.outputStates.add(node);
|
||||
tail = node;
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
Loading…
Reference in New Issue