@palasimi/ipa-cluster/dist/dsl/split.js

Cluster words with similar IPA transcriptions together

"use strict";
// SPDX-License-Identifier: GPL-3.0-or-later
// Copyright (c) 2023 Levi Gruspe
// Split intermediate representations.
Object.defineProperty(exports, "__esModule", { value: true });
exports.split = void 0;
/**
 * Compiles an `AlignedIR` into a `SplitIR`.
 * Splits each rule into simpler rules of the form `a ~ b`.
 * Also rearranges rules so that the left-hand side <= the right-hand side.
 */
function split(ir) {
    const rules = [];
    for (const rule of ir.rules) {
        const { constraint, left: leftSequence, right: rightSequence } = rule;
        for (let i = 0; i < leftSequence.length; i++) {
            // The two sequences are aligned.
            const leftSound = leftSequence[i];
            const rightSound = rightSequence[i];
            // `align` guarantees that "#" is only ever aligned with "#" or "_".
            // We can ignore such alignments, because they're not useful for
            // context matching.
            if (leftSound === "#" || rightSound === "#") {
                continue;
            }
            // We can also ignore alignments where both segments are equal,
            // because they already form a match regardless of their context.
            if (leftSound === rightSound) {
                continue;
            }
            // Define contexts.
            const leftBeforeContext = leftSequence.slice(0, i).reverse();
            const leftAfterContext = leftSequence.slice(i + 1);
            const rightBeforeContext = rightSequence.slice(0, i).reverse();
            const rightAfterContext = rightSequence.slice(i + 1);
            // Create a rule for `leftSound ~ rightSound`.
            const splitRule = {
                constraint,
                left: leftSound,
                right: rightSound,
                leftBeforeContext,
                leftAfterContext,
                rightBeforeContext,
                rightAfterContext,
            };
            rules.push(reorder(splitRule));
        }
    }
    return { rules };
}
exports.split = split;
/**
 * Reorders `left` and `rule` so that `left <= right`.
 * The other fields are adjusted accordingly.
 */
function reorder(rule) {
    if (rule.left <= rule.right) {
        return rule;
    }
    const { constraint, left, right, leftBeforeContext, leftAfterContext, rightBeforeContext, rightAfterContext, } = rule;
    return {
        constraint: {
            left: constraint.right,
            right: constraint.left,
        },
        left: right,
        right: left,
        leftBeforeContext: rightBeforeContext,
        leftAfterContext: rightAfterContext,
        rightBeforeContext: leftBeforeContext,
        rightAfterContext: leftAfterContext,
    };
}
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