hzengine-core/src/plugins/basic_command/eval.ts

An Visual Novel Engine for Zepp OS

import { HZEngineCore } from "../../index.js";

export function eval_module(core: HZEngineCore) {
  // single line eval command
  // syntax: eval <code>
  core.script.use((ctx, next) => {
    if (
      ctx.slicedArgs[0].isQuoted ||
      ctx.slicedArgs[0].str.toLowerCase() !== "eval"
    ) {
      return next();
    }
    if (ctx.slicedArgs.length === 1) {
      throw `Eval Command: no code specified`;
    }
    if (ctx.slicedArgs.length === 2) {
      core.script.evalScope(ctx.slicedArgs[1].str);
    } else {
      // delete "eval" prefix
      core.script.evalScope(ctx.rawtext.trim().slice(4).trim());
    }
  });

  // multi line eval statement (script ... end script)
  // syntax:
  // script
  // <code>
  // end script

  // script statement start
  core.script.use((ctx, next) => {
    if (ctx.rawtext.trim().split(" ")[0] !== "script") {
      return next();
    }
    let data = ctx.startStatement("script") as unknown as ScriptStatementData;
    core.script.evalScope(data.js_code_scope);
    core.script.jump(data.end_position[0], data.end_position[1]);
  });

  // script statement end
  core.script.use((ctx, next) => {
    if (ctx.rawtext.trim().split(/ +/).join(" ") !== "end script")
      return next();
    ctx.endStatement("script");
  });

  // analyze script statement start
  core.script.useAnalyseStatement((ctx, next) => {
    if (ctx.rawtext.trim().split(" ")[0] !== "script") {
      return next();
    }
    let data = ctx.startStatement("script") as unknown as ScriptStatementData;
    data.start_position = [ctx.currentPath, ctx.currentLineIndex];
    data.js_code_scope = "";
  });

  // analyze script code scope/statement end
  core.script.useAnalyseStatement((ctx, next) => {
    if (
      ctx.statementStack.length &&
      ctx.statementStack[ctx.statementStack.length - 1][0] === "script"
    ) {
      if (ctx.rawtext.trim().split(/ +/).join(" ") === "end script") {
        // end script
        let data = ctx.endStatement("script") as unknown as ScriptStatementData;
        data.end_position = [ctx.currentPath, ctx.currentLineIndex];
        ctx.setStatementData(data, [...data.start_position]);
      } else {
        // add code line to code scope
        (
          ctx.statementStack[
            ctx.statementStack.length - 1
          ][2] as unknown as ScriptStatementData
        ).js_code_scope += ctx.rawtext.trim() + '\n';
      }
    } else return next();
  }, true);
}

// eval a()
// eval"a()"
// eval "a()"

interface ScriptStatementData {
  start_position: [path: string, index: number];
  end_position: [path: string, index: number];
  js_code_scope: string;
}