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package bjc.pratt.blocks;
import java.util.function.Predicate;
import java.util.function.UnaryOperator;
import bjc.pratt.tokens.Token;
import bjc.data.Tree;
/**
* Utility class for creating common implementations of {@link ParseBlock}
*
* @author bjculkin
*
*/
public class ParseBlocks {
/*
* Grammar parse blocks are complex enough to not get a builder method.
*/
/**
* Create a new repeating parse block.
*
* @param <K> The key type for the tokens.
* @param <V> The value type for the tokens.
* @param <C> The context type for the tokens.
*
* @param inner
* The parse block to repeat.
*
* @param delim
* The token type that separates repetitions.
*
* @param term
* The token type that terminates repetitions.
*
* @param mark
* The token to use as the node in the AST.
*
* @param action
* The action to perform on the state after every repetition.
*
* @return A configured repeating parse block.
*/
public static <K, V, C> ParseBlock<K, V, C> repeating(final ParseBlock<K, V, C> inner, final K delim,
final K term, final Token<K, V> mark, final UnaryOperator<C> action) {
return new RepeatingParseBlock<>(inner, delim, term, mark, action);
}
/**
* Create a new triggered parse block.
*
* @param <K> The key type for the tokens.
* @param <V> The value type for the tokens.
* @param <C> The context type for the tokens.
*
* @param source
* The block to trigger around.
*
* @param onEnter
* The action to perform upon the state before entering the
* block.
*
* @param onExit
* The action to perform upon the state after exiting the block.
*
* @return A configured trigger parse block.
*/
public static <K, V, C> ParseBlock<K, V, C> trigger(final ParseBlock<K, V, C> source,
final UnaryOperator<C> onEnter, final UnaryOperator<C> onExit) {
return new TriggeredParseBlock<>(onEnter, onExit, source);
}
/**
* Create a new simple parse block.
*
* @param <K> The key type for the tokens.
* @param <V> The value type for the tokens.
* @param <C> The context type for the tokens.
*
* @param precedence
* The precedence of the expression inside the block.
*
* @param terminator
* The key type of the token expected after this block, or null
* if none is expected.
*
* @param validator
* The predicate to use to validate parsed expressions, or null
* if none is used.
*
* @return A configured simple parse block.
*/
public static <K, V, C> ParseBlock<K, V, C> simple(final int precedence, final K terminator,
final Predicate<Tree<Token<K, V>>> validator) {
return new SimpleParseBlock<>(precedence, validator, terminator);
}
}
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