75 lines
2.1 KiB
Plaintext
75 lines
2.1 KiB
Plaintext
import { SubstitutionAction } from './featureQuery';
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/**
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* Apply single substitution format 1
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* @param {Array} substitutions substitutions
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* @param {any} tokens a list of tokens
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* @param {number} index token index
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*/
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function singleSubstitutionFormat1(action, tokens, index) {
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tokens[index].setState(action.tag, action.substitution);
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}
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/**
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* Apply single substitution format 2
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* @param {Array} substitutions substitutions
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* @param {any} tokens a list of tokens
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* @param {number} index token index
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*/
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function singleSubstitutionFormat2(action, tokens, index) {
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tokens[index].setState(action.tag, action.substitution);
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}
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/**
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* Apply chaining context substitution format 3
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* @param {Array} substitutions substitutions
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* @param {any} tokens a list of tokens
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* @param {number} index token index
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*/
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function chainingSubstitutionFormat3(action, tokens, index) {
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action.substitution.forEach((subst, offset) => {
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const token = tokens[index + offset];
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token.setState(action.tag, subst);
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});
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}
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/**
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* Apply ligature substitution format 1
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* @param {Array} substitutions substitutions
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* @param {any} tokens a list of tokens
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* @param {number} index token index
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*/
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function ligatureSubstitutionFormat1(action, tokens, index) {
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let token = tokens[index];
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token.setState(action.tag, action.substitution.ligGlyph);
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const compsCount = action.substitution.components.length;
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for (let i = 0; i < compsCount; i++) {
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token = tokens[index + i + 1];
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token.setState('deleted', true);
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}
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}
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/**
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* Supported substitutions
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*/
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const SUBSTITUTIONS = {
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11: singleSubstitutionFormat1,
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12: singleSubstitutionFormat2,
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63: chainingSubstitutionFormat3,
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41: ligatureSubstitutionFormat1
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};
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/**
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* Apply substitutions to a list of tokens
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* @param {Array} substitutions substitutions
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* @param {any} tokens a list of tokens
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* @param {number} index token index
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*/
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function applySubstitution(action, tokens, index) {
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if (action instanceof SubstitutionAction && SUBSTITUTIONS[action.id]) {
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SUBSTITUTIONS[action.id](action, tokens, index);
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}
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}
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export default applySubstitution;
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