72 lines
2.1 KiB
Java
72 lines
2.1 KiB
Java
package expression.common;
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import base.Functional;
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import base.Pair;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.stream.Collectors;
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/**
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* @author Georgiy Korneev (kgeorgiy@kgeorgiy.info)
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*/
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public interface Renderer<C, S, R> {
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static <C, S, R> Builder<C, S, R> builder(final Node.Const<C, R> constant) {
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return new Builder<>(constant);
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}
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R render(final Expr<C, R> expr, final S settings);
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@FunctionalInterface
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interface UnaryOperator<S, R> {
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R apply(S settings, R arg);
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}
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@FunctionalInterface
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interface BinaryOperator<S, R> {
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R apply(S settings, R arg1, R arg2);
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}
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final class Builder<C, S, R> {
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private final Node.Const<C, R> constant;
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private final Map<String, UnaryOperator<S, R>> unary = new HashMap<>();
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private final Map<String, BinaryOperator<S, R>> binary =
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new HashMap<>();
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private Builder(final Node.Const<C, R> constant) {
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this.constant = constant;
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}
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public void unary(final String name, final UnaryOperator<S, R> op) {
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unary.put(name, op);
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}
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public void binary(final String name, final BinaryOperator<S, R> op) {
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binary.put(name, op);
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}
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public Renderer<C, S, R> build() {
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return (expr, settings) -> {
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final Map<String, R> vars = expr
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.variables()
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.stream()
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.collect(Collectors.toMap(Pair::first, Pair::second));
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return expr
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.node()
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.cata(
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constant,
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name -> Functional.get(vars, name),
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(name, p, arg) ->
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Functional.get(unary, name).apply(settings, arg),
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(name, arg1, arg2) ->
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Functional.get(binary, name).apply(
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settings,
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arg1,
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arg2
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)
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);
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};
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}
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}
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}
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