wehub-resource-sync
126 lines
3.6 KiB
TypeScript
126 lines
3.6 KiB
TypeScript
/**
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* 表达式构建器 — 输入校验规则
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* 1:1 翻译自 CalculatorExpressionBuilder.java
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*
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* 所有输入都在 normalized (ASCII) 空间处理
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*/
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import { normalize, localize, isDigit } from './tokenizer';
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export type CalcState = 'INPUT' | 'EVALUATE' | 'RESULT' | 'ERROR';
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/**
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* 在表达式末尾追加一个字符（或函数名），返回新的 normalized 表达式
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*
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* @param formula 当前显示表达式
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* @param token 要追加的 ASCII 字符 (e.g. '1', '+', '-', '*', '/', '.')
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* @param state 当前计算器状态
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* @param isEdited 是否已编辑过（用于 RESULT/ERROR 首次编辑替换）
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* @returns [newFormula (localized), newIsEdited]
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*/
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export function appendToken(
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formula: string,
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token: string,
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state: CalcState,
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isEdited: boolean,
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): [string, boolean] {
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const norm = normalize(formula);
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const start = norm.length;
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let editStart = start;
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let edited = isEdited;
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// RESULT/ERROR 状态下首次编辑替换全文
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if ((state === 'RESULT' || state === 'ERROR') && !edited) {
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editStart = 0;
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edited = true;
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}
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if (token === '.') {
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// 查找当前数字段中是否已有小数点
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const lastDotIdx = norm.lastIndexOf('.');
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if (lastDotIdx >= 0) {
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// 检查 lastDotIdx 之后是否全是数字（同一数字段）
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const afterDot = norm.substring(lastDotIdx + 1, start);
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const allDigits = [...afterDot].every(ch => isDigit(ch));
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if (allDigits) {
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return [formula, edited]; // 阻止重复小数点
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}
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}
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} else if (token === '+' || token === '*' || token === '/') {
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if (start === 0 && editStart === 0) {
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return [formula, edited]; // 不允许前导运算符
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}
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// 运算符总是续算：去掉尾部已有的运算符序列后追加新运算符
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// RESULT 状态下也保留公式（链式计算: 5 → 5×），不像数字那样替换
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let trimEnd = start;
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while (trimEnd > 0 && '+-*/'.includes(norm[trimEnd - 1])) {
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trimEnd--;
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}
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if (trimEnd === 0) {
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return [formula, edited]; // 全是运算符，不追加
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}
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const base = norm.substring(0, trimEnd);
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return [localize(base + token), true];
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}
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if (token === '-') {
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// 减号允许作为负号使用，也允许续算
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const checkStart = start; // 总是检查末尾字符（包括 RESULT 状态）
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if (checkStart > 0 && '+-'.includes(norm[checkStart - 1])) {
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// 替换前一个 +/- 为 -
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const base = norm.substring(0, checkStart - 1);
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return [localize(base + '-'), true];
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}
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}
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// 默认追加
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if (editStart === 0 && !edited) {
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// 替换整个表达式
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return [localize(token), true];
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}
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return [localize(norm + token), true];
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}
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/**
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* 追加函数名（自动补左括号）
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* AOSP: fun_sin onClick → append "sin("
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*/
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export function appendFunction(
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formula: string,
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funcName: string,
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state: CalcState,
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isEdited: boolean,
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): [string, boolean] {
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const norm = normalize(formula);
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let edited = isEdited;
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if ((state === 'RESULT' || state === 'ERROR') && !edited) {
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return [localize(funcName + '('), true];
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}
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return [localize(norm + funcName + '('), true];
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}
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/**
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* 删除末尾一个字符
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*/
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export function deleteLastChar(formula: string): string {
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const norm = normalize(formula);
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if (norm.length === 0) return '';
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// 检查是否以函数名 + ( 结尾（如 "sin("）
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const funcs = ['sin(', 'cos(', 'tan(', 'ln(', 'log('];
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for (const fn of funcs) {
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if (norm.endsWith(fn)) {
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return localize(norm.slice(0, -fn.length));
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}
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}
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// 检查是否以 √( 结尾
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if (norm.endsWith('sqrt(')) {
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return localize(norm.slice(0, -5));
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}
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return localize(norm.slice(0, -1));
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}
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