io.github.qudtlib.support.parse.WhitespaceTransition Maven / Gradle / Ivy

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package io.github.qudtlib.support.parse;

import java.util.ArrayDeque;
import java.util.Deque;
import java.util.List;
import java.util.regex.Pattern;

class WhitespaceTransition extends AbstractStateTransition {
    private static final Pattern P_SPACE = Pattern.compile("\\s");

    public WhitespaceTransition() {
        super("Whitespace", P_SPACE);
    }

    @Override
    protected List parse(
            State state,
            String matchedToken,
            List nextTransitions,
            List requiredClosingTransitions) {
        Deque> transitionStack =
                new ArrayDeque<>(state.getStateTransitionStack());
        if (!state.isDividerSeen() && !state.isNegativeExponentSeen()) {
            nextTransitions.add(StateTransition.DIVIDER);
        }
        pushTransitions(transitionStack, requiredClosingTransitions);
        pushTransitions(transitionStack, nextTransitions);
        return List.of(
                new State(
                        state.remainingInputForNextState(),
                        null,
                        state.getParsedUnits(),
                        state.isDividerSeen(),
                        state.isNegativeExponentSeen(),
                        transitionStack));
    }

    @Override
    protected List getRequiredClosingTransitions() {
        return List.of();
    }

    @Override
    protected List getAllowedNextTransitions() {
        return List.of(
                StateTransition.UNIT,
                StateTransition.DOT,
                StateTransition.EXPONENT,
                StateTransition.WHITESPACE,
                StateTransition.OPENING_BRACKET);
    }
}