initial version

.gitignore

+node_modules
+dist
+shell
+tsconfig.json
+.cache
+.idea

README.md

+# simple lisplike shell
+## How to use
+System Dependencies:
+- node js
+- yarn/npm
+
+## How it works
+- all programs are expressions
+- all expressions are withing round brackets () excepting:
+    - there are implicit round brackets () around the outer expression
+- expressions get parsed into an abstrace syntax tree (AST)
+    - currently 2 types of nodes (expression, assignment) and 1 atom (string)
+- the AST gets interpreted by a recursive function
+
+## What works
+- expressions/return values/outputs
+    - `> echo hi` // => hi
+- nested expressions
+    - `> echo (echo hi)` // => hi
+- `> x = echo hi` // global symbol binding (aka setting variables); lazy evaluated
+    - `> x` // calling nested expressions
+- piping, after a fashion; currently bash does the piping for us ;)
+- extending the language by writing js functions
+
+## What doesn't (yet)
+- piping inside the language (currently bash does it)
+- local variables/context/`this`
+- symbols with arguments (aka functions with arguments)
+    - `> f x = echo (x)`
+    - `> + x y = echo (x)+(y) | bc`
+- extending the language with macros (functions on the raw ast)

evaluate.js

+const chalk = require('chalk');
+const execa = require("execa");
+
+symbols = {
+    info: async function (symbol, args) {
+        return `hallo lieber erdling. ich bin eine seltsame Kreuzung aus bash, lisp und haskell. Noch kann man mich keine Missgeburt taufen, denn es ist ja kaum der Kopf noch nicht draußen...`;
+    },
+    run: async function (symbol, args) {
+        let result = "";
+        try {
+            result = await execa.shell(symbol + " " + args.join(" "));
+        } catch (e) {
+            return chalk.red(e);
+        }
+        return result.stdout;
+    },
+    debug: async function (symbol, args) {
+        console.log(chalk.green(JSON.stringify(args)));
+        console.log(symbols.f.toString());
+    }
+};
+
+function symbolFactory(symbol, args) {
+    symbols[symbol] = function () {
+
+    };
+}
+
+/**
+ * returns a function that can be called with arguments
+ * @param symbol
+ */
+function lookup(symbol) {
+    if (symbols.hasOwnProperty(symbol)) {
+        return symbols[symbol];
+    }
+    return symbols.run;
+}
+
+async function evaluate(command) {
+    if (typeof command === "string") {
+        return command;
+    }
+    // command is an object
+    switch (command.type) {
+        case "command":
+            // first evaluate all children nodes
+            for (let i = 0; i < command.data.length; i++) {
+                command.data[i] = await evaluate((command.data[i]));
+            }
+            return await lookup(command.symbol)(command.symbol, command.data);
+            break;
+        case "assignment":
+            symbols[command.symbol] = async (symbol, args) => { // args not used
+                // for (let i = 0; i < command.data.length; i++) {
+                //     command.data[i] = await evaluate((command.data[i]));
+                // }
+                return evaluate({
+                    "type": "command",
+                    "symbol": command.data[0],
+                    "data": command.data.slice(1)
+                });
+            };
+            //throw "Error: assignment not implemented";
+            break;
+    }
+}
+module.exports = evaluate;

grammar.js

+/*
+ * Generated by PEG.js 0.10.0.
+ *
+ * http://pegjs.org/
+ */
+
+"use strict";
+
+function peg$subclass(child, parent) {
+  function ctor() { this.constructor = child; }
+  ctor.prototype = parent.prototype;
+  child.prototype = new ctor();
+}
+
+function peg$SyntaxError(message, expected, found, location) {
+  this.message  = message;
+  this.expected = expected;
+  this.found    = found;
+  this.location = location;
+  this.name     = "SyntaxError";
+
+  if (typeof Error.captureStackTrace === "function") {
+    Error.captureStackTrace(this, peg$SyntaxError);
+  }
+}
+
+peg$subclass(peg$SyntaxError, Error);
+
+peg$SyntaxError.buildMessage = function(expected, found) {
+  var DESCRIBE_EXPECTATION_FNS = {
+        literal: function(expectation) {
+          return "\"" + literalEscape(expectation.text) + "\"";
+        },
+
+        "class": function(expectation) {
+          var escapedParts = "",
+              i;
+
+          for (i = 0; i < expectation.parts.length; i++) {
+            escapedParts += expectation.parts[i] instanceof Array
+              ? classEscape(expectation.parts[i][0]) + "-" + classEscape(expectation.parts[i][1])
+              : classEscape(expectation.parts[i]);
+          }
+
+          return "[" + (expectation.inverted ? "^" : "") + escapedParts + "]";
+        },
+
+        any: function(expectation) {
+          return "any character";
+        },
+
+        end: function(expectation) {
+          return "end of input";
+        },
+
+        other: function(expectation) {
+          return expectation.description;
+        }
+      };
+
+  function hex(ch) {
+    return ch.charCodeAt(0).toString(16).toUpperCase();
+  }
+
+  function literalEscape(s) {
+    return s
+      .replace(/\\/g, '\\\\')
+      .replace(/"/g,  '\\"')
+      .replace(/\0/g, '\\0')
+      .replace(/\t/g, '\\t')
+      .replace(/\n/g, '\\n')
+      .replace(/\r/g, '\\r')
+      .replace(/[\x00-\x0F]/g,          function(ch) { return '\\x0' + hex(ch); })
+      .replace(/[\x10-\x1F\x7F-\x9F]/g, function(ch) { return '\\x'  + hex(ch); });
+  }
+
+  function classEscape(s) {
+    return s
+      .replace(/\\/g, '\\\\')
+      .replace(/\]/g, '\\]')
+      .replace(/\^/g, '\\^')
+      .replace(/-/g,  '\\-')
+      .replace(/\0/g, '\\0')
+      .replace(/\t/g, '\\t')
+      .replace(/\n/g, '\\n')
+      .replace(/\r/g, '\\r')
+      .replace(/[\x00-\x0F]/g,          function(ch) { return '\\x0' + hex(ch); })
+      .replace(/[\x10-\x1F\x7F-\x9F]/g, function(ch) { return '\\x'  + hex(ch); });
+  }
+
+  function describeExpectation(expectation) {
+    return DESCRIBE_EXPECTATION_FNS[expectation.type](expectation);
+  }
+
+  function describeExpected(expected) {
+    var descriptions = new Array(expected.length),
+        i, j;
+
+    for (i = 0; i < expected.length; i++) {
+      descriptions[i] = describeExpectation(expected[i]);
+    }
+
+    descriptions.sort();
+
+    if (descriptions.length > 0) {
+      for (i = 1, j = 1; i < descriptions.length; i++) {
+        if (descriptions[i - 1] !== descriptions[i]) {
+          descriptions[j] = descriptions[i];
+          j++;
+        }
+      }
+      descriptions.length = j;
+    }
+
+    switch (descriptions.length) {
+      case 1:
+        return descriptions[0];
+
+      case 2:
+        return descriptions[0] + " or " + descriptions[1];
+
+      default:
+        return descriptions.slice(0, -1).join(", ")
+          + ", or "
+          + descriptions[descriptions.length - 1];
+    }
+  }
+
+  function describeFound(found) {
+    return found ? "\"" + literalEscape(found) + "\"" : "end of input";
+  }
+
+  return "Expected " + describeExpected(expected) + " but " + describeFound(found) + " found.";
+};
+
+function peg$parse(input, options) {
+  options = options !== void 0 ? options : {};
+
+  var peg$FAILED = {},
+
+      peg$startRuleFunctions = { Command: peg$parseCommand },
+      peg$startRuleFunction  = peg$parseCommand,
+
+      peg$c0 = "=",
+      peg$c1 = peg$literalExpectation("=", false),
+      peg$c2 = function(symbol, args, cmd) {
+          	return {
+              	"type": "assignment",
+              	"symbol": symbol,
+                  "args": args.map(x=>x[0]),
+                  "data": cmd.map(x=>x[0])
+              }
+          },
+      peg$c3 = function(symbol, cmd) {
+          	return {
+              	"type": "command",
+                  "symbol": symbol,
+                  "data": cmd.map(x=>x[0])
+              }
+          },
+      peg$c4 = "",
+      peg$c5 = "(",
+      peg$c6 = peg$literalExpectation("(", false),
+      peg$c7 = ")",
+      peg$c8 = peg$literalExpectation(")", false),
+      peg$c9 = function(s) { return s },
+      peg$c10 = /^[a-zA-Z0-9*+|]/,
+      peg$c11 = peg$classExpectation([["a", "z"], ["A", "Z"], ["0", "9"], "*", "+", "|"], false, false),
+      peg$c12 = function(s) { return s.join(""); },
+      peg$c13 = peg$otherExpectation("whitespace"),
+      peg$c14 = /^[ \t\r]/,
+      peg$c15 = peg$classExpectation([" ", "\t", "\r"], false, false),
+
+      peg$currPos          = 0,
+      peg$savedPos         = 0,
+      peg$posDetailsCache  = [{ line: 1, column: 1 }],
+      peg$maxFailPos       = 0,
+      peg$maxFailExpected  = [],
+      peg$silentFails      = 0,
+
+      peg$result;
+
+  if ("startRule" in options) {
+    if (!(options.startRule in peg$startRuleFunctions)) {
+      throw new Error("Can't start parsing from rule \"" + options.startRule + "\".");
+    }
+
+    peg$startRuleFunction = peg$startRuleFunctions[options.startRule];
+  }
+
+  function text() {
+    return input.substring(peg$savedPos, peg$currPos);
+  }
+
+  function location() {
+    return peg$computeLocation(peg$savedPos, peg$currPos);
+  }
+
+  function expected(description, location) {
+    location = location !== void 0 ? location : peg$computeLocation(peg$savedPos, peg$currPos)
+
+    throw peg$buildStructuredError(
+      [peg$otherExpectation(description)],
+      input.substring(peg$savedPos, peg$currPos),
+      location
+    );
+  }
+
+  function error(message, location) {
+    location = location !== void 0 ? location : peg$computeLocation(peg$savedPos, peg$currPos)
+
+    throw peg$buildSimpleError(message, location);
+  }
+
+  function peg$literalExpectation(text, ignoreCase) {
+    return { type: "literal", text: text, ignoreCase: ignoreCase };
+  }
+
+  function peg$classExpectation(parts, inverted, ignoreCase) {
+    return { type: "class", parts: parts, inverted: inverted, ignoreCase: ignoreCase };
+  }
+
+  function peg$anyExpectation() {
+    return { type: "any" };
+  }
+
+  function peg$endExpectation() {
+    return { type: "end" };
+  }
+
+  function peg$otherExpectation(description) {
+    return { type: "other", description: description };
+  }
+
+  function peg$computePosDetails(pos) {
+    var details = peg$posDetailsCache[pos], p;
+
+    if (details) {
+      return details;
+    } else {
+      p = pos - 1;
+      while (!peg$posDetailsCache[p]) {
+        p--;
+      }
+
+      details = peg$posDetailsCache[p];
+      details = {
+        line:   details.line,
+        column: details.column
+      };
+
+      while (p < pos) {
+        if (input.charCodeAt(p) === 10) {
+          details.line++;
+          details.column = 1;
+        } else {
+          details.column++;
+        }
+
+        p++;
+      }
+
+      peg$posDetailsCache[pos] = details;
+      return details;
+    }
+  }
+
+  function peg$computeLocation(startPos, endPos) {
+    var startPosDetails = peg$computePosDetails(startPos),
+        endPosDetails   = peg$computePosDetails(endPos);
+
+    return {
+      start: {
+        offset: startPos,
+        line:   startPosDetails.line,
+        column: startPosDetails.column
+      },
+      end: {
+        offset: endPos,
+        line:   endPosDetails.line,
+        column: endPosDetails.column
+      }
+    };
+  }
+
+  function peg$fail(expected) {
+    if (peg$currPos < peg$maxFailPos) { return; }
+
+    if (peg$currPos > peg$maxFailPos) {
+      peg$maxFailPos = peg$currPos;
+      peg$maxFailExpected = [];
+    }
+
+    peg$maxFailExpected.push(expected);
+  }
+
+  function peg$buildSimpleError(message, location) {
+    return new peg$SyntaxError(message, null, null, location);
+  }
+
+  function peg$buildStructuredError(expected, found, location) {
+    return new peg$SyntaxError(
+      peg$SyntaxError.buildMessage(expected, found),
+      expected,
+      found,
+      location
+    );
+  }
+
+  function peg$parseCommand() {
+    var s0, s1, s2, s3, s4, s5, s6, s7, s8, s9;
+
+    s0 = peg$currPos;
+    s1 = peg$parseString();
+    if (s1 !== peg$FAILED) {
+      s2 = peg$parse_();
+      if (s2 !== peg$FAILED) {
+        s3 = [];
+        s4 = peg$currPos;
+        s5 = peg$parseString();
+        if (s5 !== peg$FAILED) {
+          s6 = peg$parse_();
+          if (s6 !== peg$FAILED) {
+            s5 = [s5, s6];
+            s4 = s5;
+          } else {
+            peg$currPos = s4;
+            s4 = peg$FAILED;
+          }
+        } else {
+          peg$currPos = s4;
+          s4 = peg$FAILED;
+        }
+        while (s4 !== peg$FAILED) {
+          s3.push(s4);
+          s4 = peg$currPos;
+          s5 = peg$parseString();
+          if (s5 !== peg$FAILED) {
+            s6 = peg$parse_();
+            if (s6 !== peg$FAILED) {
+              s5 = [s5, s6];
+              s4 = s5;
+            } else {
+              peg$currPos = s4;
+              s4 = peg$FAILED;
+            }
+          } else {
+            peg$currPos = s4;
+            s4 = peg$FAILED;
+          }
+        }
+        if (s3 !== peg$FAILED) {
+          if (input.charCodeAt(peg$currPos) === 61) {
+            s4 = peg$c0;
+            peg$currPos++;
+          } else {
+            s4 = peg$FAILED;
+            if (peg$silentFails === 0) { peg$fail(peg$c1); }
+          }
+          if (s4 !== peg$FAILED) {
+            s5 = peg$parse_();
+            if (s5 !== peg$FAILED) {
+              s6 = [];
+              s7 = peg$currPos;
+              s8 = peg$parseSubCommand();
+              if (s8 !== peg$FAILED) {
+                s9 = peg$parse_();
+                if (s9 !== peg$FAILED) {
+                  s8 = [s8, s9];
+                  s7 = s8;
+                } else {
+                  peg$currPos = s7;
+                  s7 = peg$FAILED;
+                }
+              } else {
+                peg$currPos = s7;
+                s7 = peg$FAILED;
+              }
+              if (s7 !== peg$FAILED) {
+                while (s7 !== peg$FAILED) {
+                  s6.push(s7);
+                  s7 = peg$currPos;
+                  s8 = peg$parseSubCommand();
+                  if (s8 !== peg$FAILED) {
+                    s9 = peg$parse_();
+                    if (s9 !== peg$FAILED) {
+                      s8 = [s8, s9];
+                      s7 = s8;
+                    } else {
+                      peg$currPos = s7;
+                      s7 = peg$FAILED;
+                    }
+                  } else {
+                    peg$currPos = s7;
+                    s7 = peg$FAILED;
+                  }
+                }
+              } else {
+                s6 = peg$FAILED;
+              }
+              if (s6 !== peg$FAILED) {
+                peg$savedPos = s0;
+                s1 = peg$c2(s1, s3, s6);
+                s0 = s1;
+              } else {
+                peg$currPos = s0;
+                s0 = peg$FAILED;
+              }
+            } else {
+              peg$currPos = s0;
+              s0 = peg$FAILED;
+            }
+          } else {
+            peg$currPos = s0;
+            s0 = peg$FAILED;
+          }
+        } else {
+          peg$currPos = s0;
+          s0 = peg$FAILED;
+        }
+      } else {
+        peg$currPos = s0;
+        s0 = peg$FAILED;
+      }
+    } else {
+      peg$currPos = s0;
+      s0 = peg$FAILED;
+    }
+    if (s0 === peg$FAILED) {
+      s0 = peg$currPos;
+      s1 = peg$parseString();
+      if (s1 !== peg$FAILED) {
+        s2 = peg$parse_();
+        if (s2 !== peg$FAILED) {
+          s3 = [];
+          s4 = peg$currPos;
+          s5 = peg$parseSubCommand();
+          if (s5 !== peg$FAILED) {
+            s6 = peg$parse_();
+            if (s6 !== peg$FAILED) {
+              s5 = [s5, s6];
+              s4 = s5;
+            } else {
+              peg$currPos = s4;
+              s4 = peg$FAILED;
+            }
+          } else {
+            peg$currPos = s4;
+            s4 = peg$FAILED;
+          }
+          while (s4 !== peg$FAILED) {
+            s3.push(s4);
+            s4 = peg$currPos;
+            s5 = peg$parseSubCommand();
+            if (s5 !== peg$FAILED) {
+              s6 = peg$parse_();
+              if (s6 !== peg$FAILED) {
+                s5 = [s5, s6];
+                s4 = s5;
+              } else {
+                peg$currPos = s4;
+                s4 = peg$FAILED;
+              }
+            } else {
+              peg$currPos = s4;
+              s4 = peg$FAILED;
+            }
+          }
+          if (s3 !== peg$FAILED) {
+            peg$savedPos = s0;
+            s1 = peg$c3(s1, s3);
+            s0 = s1;
+          } else {
+            peg$currPos = s0;
+            s0 = peg$FAILED;
+          }
+        } else {
+          peg$currPos = s0;
+          s0 = peg$FAILED;
+        }
+      } else {
+        peg$currPos = s0;
+        s0 = peg$FAILED;
+      }
+      if (s0 === peg$FAILED) {
+        s0 = peg$c4;
+      }
+    }
+
+    return s0;
+  }
+
+  function peg$parseSubCommand() {
+    var s0, s1, s2, s3, s4, s5, s6, s7;
+
+    s0 = peg$currPos;
+    if (input.charCodeAt(peg$currPos) === 40) {
+      s1 = peg$c5;
+      peg$currPos++;
+    } else {
+      s1 = peg$FAILED;
+      if (peg$silentFails === 0) { peg$fail(peg$c6); }
+    }
+    if (s1 !== peg$FAILED) {
+      s2 = peg$parseString();
+      if (s2 !== peg$FAILED) {
+        s3 = peg$parse_();
+        if (s3 !== peg$FAILED) {
+          s4 = [];
+          s5 = peg$currPos;
+          s6 = peg$parseSubCommand();
+          if (s6 !== peg$FAILED) {
+            s7 = peg$parse_();
+            if (s7 !== peg$FAILED) {
+              s6 = [s6, s7];
+              s5 = s6;
+            } else {
+              peg$currPos = s5;
+              s5 = peg$FAILED;
+            }
+          } else {
+            peg$currPos = s5;
+            s5 = peg$FAILED;
+          }
+          while (s5 !== peg$FAILED) {
+            s4.push(s5);
+            s5 = peg$currPos;
+            s6 = peg$parseSubCommand();
+            if (s6 !== peg$FAILED) {
+              s7 = peg$parse_();
+              if (s7 !== peg$FAILED) {
+                s6 = [s6, s7];
+                s5 = s6;
+              } else {
+                peg$currPos = s5;
+                s5 = peg$FAILED;
+              }
+            } else {
+              peg$currPos = s5;
+              s5 = peg$FAILED;
+            }
+          }
+          if (s4 !== peg$FAILED) {
+            if (input.charCodeAt(peg$currPos) === 41) {
+              s5 = peg$c7;
+              peg$currPos++;
+            } else {
+              s5 = peg$FAILED;
+              if (peg$silentFails === 0) { peg$fail(peg$c8); }
+            }
+            if (s5 !== peg$FAILED) {
+              peg$savedPos = s0;
+              s1 = peg$c3(s2, s4);
+              s0 = s1;
+            } else {
+              peg$currPos = s0;
+              s0 = peg$FAILED;
+            }
+          } else {
+            peg$currPos = s0;
+            s0 = peg$FAILED;
+          }
+        } else {
+          peg$currPos = s0;
+          s0 = peg$FAILED;
+        }
+      } else {
+        peg$currPos = s0;
+        s0 = peg$FAILED;
+      }
+    } else {
+      peg$currPos = s0;
+      s0 = peg$FAILED;
+    }
+    if (s0 === peg$FAILED) {
+      s0 = peg$currPos;
+      s1 = peg$parseString();
+      if (s1 !== peg$FAILED) {
+        peg$savedPos = s0;
+        s1 = peg$c9(s1);
+      }
+      s0 = s1;
+    }
+
+    return s0;
+  }
+
+  function peg$parseString() {
+    var s0, s1, s2;
+
+    s0 = peg$currPos;
+    s1 = [];
+    if (peg$c10.test(input.charAt(peg$currPos))) {
+      s2 = input.charAt(peg$currPos);
+      peg$currPos++;
+    } else {
+      s2 = peg$FAILED;
+      if (peg$silentFails === 0) { peg$fail(peg$c11); }
+    }
+    if (s2 !== peg$FAILED) {
+      while (s2 !== peg$FAILED) {
+        s1.push(s2);
+        if (peg$c10.test(input.charAt(peg$currPos))) {
+          s2 = input.charAt(peg$currPos);
+          peg$currPos++;
+        } else {
+          s2 = peg$FAILED;
+          if (peg$silentFails === 0) { peg$fail(peg$c11); }
+        }
+      }
+    } else {
+      s1 = peg$FAILED;
+    }
+    if (s1 !== peg$FAILED) {
+      peg$savedPos = s0;
+      s1 = peg$c12(s1);
+    }
+    s0 = s1;
+
+    return s0;
+  }
+
+  function peg$parse_() {
+    var s0, s1;
+
+    peg$silentFails++;
+    s0 = [];
+    if (peg$c14.test(input.charAt(peg$currPos))) {
+      s1 = input.charAt(peg$currPos);
+      peg$currPos++;
+    } else {
+      s1 = peg$FAILED;
+      if (peg$silentFails === 0) { peg$fail(peg$c15); }
+    }
+    while (s1 !== peg$FAILED) {
+      s0.push(s1);
+      if (peg$c14.test(input.charAt(peg$currPos))) {
+        s1 = input.charAt(peg$currPos);
+        peg$currPos++;
+      } else {
+        s1 = peg$FAILED;
+        if (peg$silentFails === 0) { peg$fail(peg$c15); }
+      }
+    }
+    peg$silentFails--;
+    if (s0 === peg$FAILED) {
+      s1 = peg$FAILED;
+      if (peg$silentFails === 0) { peg$fail(peg$c13); }
+    }
+
+    return s0;
+  }
+
+  peg$result = peg$startRuleFunction();
+
+  if (peg$result !== peg$FAILED && peg$currPos === input.length) {
+    return peg$result;
+  } else {
+    if (peg$result !== peg$FAILED && peg$currPos < input.length) {
+      peg$fail(peg$endExpectation());
+    }
+
+    throw peg$buildStructuredError(
+      peg$maxFailExpected,
+      peg$maxFailPos < input.length ? input.charAt(peg$maxFailPos) : null,
+      peg$maxFailPos < input.length
+        ? peg$computeLocation(peg$maxFailPos, peg$maxFailPos + 1)
+        : peg$computeLocation(peg$maxFailPos, peg$maxFailPos)
+    );
+  }
+}
+
+module.exports = {
+  SyntaxError: peg$SyntaxError,
+  parse:       peg$parse
+};

grammar.pegjs

+
+
+Command
+	= symbol:String _ args:( String _)* '=' _ cmd:( SubCommand _)+ {
+    	return {
+        	"type": "assignment",
+        	"symbol": symbol,
+            "args": args.map(x=>x[0]),
+            "data": cmd.map(x=>x[0])
+        }
+    }
+    / symbol:String _ cmd:( SubCommand _)* {
+    	return {
+        	"type": "command",
+            "symbol": symbol,
+            "data": cmd.map(x=>x[0])
+        }
+    }
+    / ""
+    //{ return cmd.map(x => x[0]) }
+
+SubCommand
+	= '(' symbol:String _ cmd:( SubCommand _)* ')' {
+    	return {
+        	"type": "command",
+            "symbol": symbol,
+            "data": cmd.map(x=>x[0])
+        }
+    }
+	/ s:String { return s }
+
+String = s:[a-zA-Z0-9\*\+|]+ { return s.join(""); }
+
+_ "whitespace"
+	= [ \t\r]*

index.js

+let grammar = require("./grammar");
+let evaluate = require("./evaluate");
+
+var readline = require('readline');
+var rl = readline.createInterface({
+    input: process.stdin,
+    output: process.stdout,
+    terminal: true
+});
+rl.setPrompt("> ");
+rl.prompt();
+
+rl.on('line', function(line){
+    evaluate(grammar.parse(line)).then((result) => {
+        console.log(result);
+        rl.prompt();
+    });
+});

package.json

+{
+  "name": "shell",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "dependencies": {
+    "chalk": "^2.4.2",
+    "execa": "^1.0.0",
+    "immutable": "^4.0.0-rc.12",
+    "parcel": "^1.12.3",
+    "pegjs": "^0.10.0"
+  },
+  "scripts": {
+    "start": "npx pegjs grammar.pegjs && node index.js",
+    "bundle": "npx parcel "
+  }
+}

run.sh

+