54 lines
1.7 KiB
JavaScript
54 lines
1.7 KiB
JavaScript
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// 表达式函数解析，为突破小程序不支持js实现的折中方案
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function evaluate(env, expr) {
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const tokens = expr.split(/(?![^(]*\)),/); // 分割外层参数，忽略内层逗号
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return tokens.map((token) => {
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if (token.trim().startsWith('\'') && token.trim().endsWith('\'')) {
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// 处理字符串字面量
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return token.trim().slice(1, -1);
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} else if (/^[0-9]+(\.[0-9]+)?$/.test(token.trim())) {
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// 处理数字字面量
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return parseFloat(token);
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} else if (/^[A-Za-z_]\w*\(/.test(token.trim())) {
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// 处理函数调用
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const fnName = token.trim().substring(0, token.indexOf('('));
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const args = token.trim().slice(token.indexOf('(') + 1, -1); // 提取参数部分
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if (!(fnName in env)) {
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throw new Error(`Function '${fnName}' is not defined`);
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}
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return env[fnName](...evaluate(env, args));
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} else {
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// 处理变量
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if (!(token.trim() in env)) {
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throw new Error(`Variable '${token.trim()}' is not defined`);
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}
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return env[token.trim()];
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}
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});
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}
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export function interpret(env, expression) {
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if (!/^[A-Za-z_]\w*\(/.test(expression)) {
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throw new Error('Expression must start with a function call');
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}
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const fnName = expression.substring(0, expression.indexOf('('));
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const argsString = expression.substring(expression.indexOf('(') + 1, expression.lastIndexOf(')'));
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if (!(fnName in env)) {
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throw new Error(`函数 '${fnName}' 未定义`);
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}
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const args = evaluate(env, argsString);
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try {
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return env[fnName](...args);
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} catch (e) {
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throw new Error(`执行错误 '${fnName}': ${e.message}`);
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}
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}
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export default {
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interpret
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}
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