web_repl.js

/* vim:fileencoding=utf-8
 *
 * Copyright (C) 2016 Kovid Goyal <kovid at kovidgoyal.net>
 *
 * Distributed under terms of the BSD license
 */
"use strict"; /*jshint node:true */
var vm = require("vm");
var embedded_compiler = require("tools/embedded_compiler.js");

module.exports = function (compiler, baselib) {
  var ctx = vm.createContext();
  var LINE_CONTINUATION_CHARS = ":\\";
  var find_completions = null;
  var streaming_compiler = embedded_compiler(
    compiler,
    baselib,
    function (js) {
      return vm.runInContext(js, ctx);
    },
    "__repl__"
  );

  return {
    in_block_mode: false,

    replace_print: (write_line_func) => {
      ctx.print = function () {
        var parts = [];
        for (var i = 0; i < arguments.length; i++)
          parts.push(ctx.ρσ_str(arguments[i]));
        write_line_func(parts.join(" "));
      };
    },

    is_input_complete: (source) => {
      if (!source || !source.trim()) return false;
      var lines = source.split("\n");
      var last_line = lines[lines.length - 1].trimRight();
      if (this.in_block_mode) {
        // In a block only exit after two blank lines
        if (lines.length < 2) return false;
        var second_last_line = lines[lines.length - 2].trimRight();
        var block_ended = !!(!last_line && !second_last_line);
        if (!block_ended) return false;
        this.in_block_mode = false;
        return true;
      }

      if (
        last_line &&
        LINE_CONTINUATION_CHARS.indexOf(
          last_line.substr(last_line.length - 1)
        ) > -1
      ) {
        this.in_block_mode = true;
        return false;
      }
      try {
        compiler.parse(source, { filename: "<repl>", basedir: "__stdlib__" });
      } catch (e) {
        if (e.is_eof && e.line === lines.length && e.col > 0) {
          return false;
        }
        this.in_block_mode = false;
        return true;
      }
      this.in_block_mode = false;
      return true;
    },

    compile: (code, opts) => {
      opts = opts || {};
      opts.keep_docstrings = true;
      opts.filename = "<input>";
      return streaming_compiler.compile(code, opts);
    },

    runjs: (code) => {
      var ans = vm.runInContext(code, ctx);
      if (ans !== undefined || ans === null) {
        ctx.ρσ_repl_val = ans;
        var q = vm.runInContext("ρσ_repr(ρσ_repl_val)", ctx);
        ans = q === "undefined" ? ans.toString() : q;
      }
      return ans;
    },

    init_completions: (completelib) => {
      find_completions = completelib(compiler);
    },

    find_completions: (line) => {
      return find_completions(line, ctx);
    },
  };
};