Fixed parsing bug, began adding 'fromScript' support, and added test.

Fixed a bug in the AFTER fragment that used a token's 'parse' method instead of the parseContext's 'parse'. Also added the 'fromScript' method to a few fragments to allow conversions from ASM to miniscript strings. Jest was added as a test runner and a single 'fromScript' test has been added.

Author: Randy808

examples/quick-start.ts

@@ -1,4 +1,7 @@
 import Miniscript from "..";
 
-let rootExpression = Miniscript.parse("thresh(1,pk(0xA),s:pk(0xB))");
+let rootExpression = Miniscript.parse("and_v(v:pk(key),or_b(l:after(100),al:after(200)))");
 console.log(rootExpression.toScript());
+
+// console.log(Miniscript.parseScript("7 OP_CHECKLOCKTIMEVERIFY 4 OP_CHECKLOCKTIMEVERIFY 2 OP_EQUAL"));
+

index.ts

@@ -28,4 +28,12 @@ export default class Miniscript {
     let parser = new Parser(expressions, wrappers);
     return parser.parse(tokens);
   }
+
+  static parseScript(
+    input: string,
+  ): any {
+    let parser = new Parser(expressions, wrappers);
+    let reversedScript = input.split(" ").reverse();
+    return parser.parseScript(reversedScript);
+  }
 }

jest.config.js

@@ -0,0 +1,5 @@
+/** @type {import('ts-jest').JestConfigWithTsJest} */
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+};

modules/bitcoin-miniscript/fragments/AFTER.ts

@@ -1,4 +1,4 @@
-import { NUMBER } from "../../../universal-tokens";
+import { CLOSE_PAREN, NUMBER } from "../../../universal-tokens";
 import { lexKeyword } from "../../../lex-utils";
 import { Types } from "../../../miniscript-types";
 import {
@@ -37,10 +37,12 @@ export class AFTER
   static parse = (parseContext: ParseContext) => {
     parseContext.eat(this.tokenType);
 
-    let locktime = NUMBER.parse(parseContext);
+    let locktime = parseContext.eat(NUMBER.tokenType)?.value;
 
     this.validateLocktime(locktime);
 
+    parseContext.eat(CLOSE_PAREN.tokenType);
+
     return new AFTER(locktime);
   };
 
@@ -77,15 +79,21 @@ export class AFTER
     return `${this.locktime} OP_CHECKLOCKTIMEVERIFY`;
   };
 
-  static fromScript = (opcodes: string[]) => {
-    let locktime = parseInt(opcodes[1]);
-    if (isNaN(locktime)) {
+  static fromScript = (scriptParseContext: any) => {
+    let {reversedScript} = scriptParseContext;
+    if (reversedScript[0] != "OP_CHECKLOCKTIMEVERIFY") {
       return;
     }
 
-    if (opcodes[0] == "OP_CHECKLOCKTIMEVERIFY") {
-      return new AFTER(locktime);
+    let locktime = parseInt(reversedScript[1]);
+    if (isNaN(locktime)) {
+      return;
     }
+
+    reversedScript.shift();
+    reversedScript.shift();
+
+    return new AFTER(locktime);
   };
 
   private static validateLocktime(locktime: number) {

modules/bitcoin-miniscript/fragments/ANDOR.ts

@@ -171,7 +171,7 @@ export class ANDOR
       `\n${indent(this.children[2].toScript())}\n` +
       `OP_ELSE` +
       `\n${indent(this.children[1].toScript())}\n` +
-      `OP_ENDIF`
+      `OP_ENDIF\n`
     );
   };
 }

modules/bitcoin-miniscript/fragments/OR_I.ts

@@ -119,8 +119,8 @@ export class OR_I
       `OP_IF` +
       `\n${indent(this.children[0].toScript())}\n` +
       `OP_ELSE` +
-      `\n${this.children[1].toScript()}\n` +
-      `OP_ENDIF`
+      `\n${indent(this.children[1].toScript())}\n` +
+      `OP_ENDIF\n`
     );
   };
 }

modules/bitcoin-miniscript/fragments/SHA256.ts

@@ -1,6 +1,5 @@
 import { lexKeyword } from "../../../lex-utils";
 import { Types } from "../../../miniscript-types";
-import { eat } from "../../../parse-utils";
 import { ParseContext } from "../../../parser";
 import {
   MiniscriptFragmentStatic,
@@ -55,7 +54,9 @@ export class SHA256
     parseContext.eat(CLOSE_PAREN.tokenType);
 
     if (!stringToken?.value) {
-      throw new Error(`String not found while parsing string in ${SHA256.tokenType}`);
+      throw new Error(
+        `String not found while parsing string in ${SHA256.tokenType}`
+      );
     }
 
     return new SHA256(stringToken.value as string);

modules/bitcoin-miniscript/fragments/THRESH.ts

@@ -202,4 +202,37 @@ export class THRESH
       script + " " + this.k + " " + (verify ? `OP_EQUALVERIFY` : `OP_EQUAL`)
     );
   };
+
+  static fromScript = (scriptParseContext: any) => {
+    let { reversedScript } = scriptParseContext;
+    if (reversedScript[0] != "OP_EQUAL") {
+      return;
+    }
+    let threshold = parseInt(reversedScript[1]);
+    if (isNaN(threshold)) {
+      return;
+    }
+
+    reversedScript.shift();
+    reversedScript.shift();
+
+    let i = threshold;
+    let x;
+    let children: any[] = [];
+    do {
+      if (i + 1 < threshold) {
+        let OP_ADD = reversedScript.shift();
+        if (OP_ADD != "OP_ADD") {
+          throw new Error();
+        }
+      }
+
+      x = scriptParseContext.parser.parseScript(reversedScript);
+      if(x) {
+        children.push(x);
+      }
+    } while (x);
+
+    return new THRESH(children, threshold);
+  };
 }

modules/bitcoin-miniscript/fragments/WRAP_A.ts

@@ -86,6 +86,6 @@ export class WRAP_A
   };
 
   toScript = () => {
-    return `TOALTSTACK ${this.children[0].toScript()} FROMALTSTACK`;
+    return `OP_TOALTSTACK ${this.children[0].toScript()} OP_FROMALTSTACK`;
   };
 }