fix: make globals static so that they don't pollute downstream libraries (#42)

Also reorganized top level `let`s into static variables.

Author: Willem Wyndham

.prettierignore

@@ -1,2 +1,3 @@
 # prettier doesn't support decorators on functions :-(
-assembly/char.ts
+assembly/char.ts
+assembly/nfa/types.ts

asconfig.empty.json

@@ -0,0 +1,8 @@
+{
+  "options": {
+    "runtime": "stub",
+    "textFile": "build/empty.wat",
+    "debug": true
+  },
+  "entries": ["assembly/__tests__/empty.ts"]
+}

assembly/__tests__/empty.ts

@@ -0,0 +1 @@
+import * as regex from "..";

assembly/__tests__/empty.wat

@@ -0,0 +1,5 @@
+(module
+ (memory $0 0)
+ (table $0 1 funcref)
+ (export "memory" (memory $0))
+)

assembly/char.ts

@@ -1,3 +1,5 @@
+// @ts-ignore
+@lazy
 export const enum Char {
   None = -1,
   HorizontalTab = 0x09,

assembly/nfa/matcher.ts

@@ -16,10 +16,9 @@ const enum MatcherType {
   CharacterSet,
   CharacterClass,
 }
-
-let _flags: Flags;
-
 export class Matcher {
+  @lazy static _flags: Flags;
+
   constructor(readonly type: MatcherType) {}
 
   matches(code: u32): bool {
@@ -47,20 +46,23 @@ export class Matcher {
     node: CharacterClassNode,
     flags: Flags
   ): CharacterClassMatcher {
-    _flags = flags;
+    Matcher._flags = flags;
     const matchers = node.expressions.map<Matcher>((exp) => {
       switch (exp.type) {
         case NodeType.CharacterRange:
           return Matcher.fromCharacterRangeNode(
             exp as CharacterRangeNode,
-            _flags
+            Matcher._flags
           );
         case NodeType.Character:
-          return Matcher.fromCharacterNode(exp as CharacterNode, _flags);
+          return Matcher.fromCharacterNode(
+            exp as CharacterNode,
+            Matcher._flags
+          );
         case NodeType.CharacterSet:
           return Matcher.fromCharacterClassNode(
             exp as CharacterSetNode,
-            _flags
+            Matcher._flags
           );
         default:
           throw new Error("unsupported node type within character set");
@@ -93,9 +95,12 @@ export class CharacterMatcher extends Matcher {
   }
 }
 
-const LOWERCASE_LETTERS = new Range(Char.a, Char.z);
-const UPPERCASE_LETTERS = new Range(Char.A, Char.Z);
-const UPPER_LOWER_OFFSET = Char.a - Char.A;
+// @ts-ignore
+@lazy const LOWERCASE_LETTERS = new Range(Char.a, Char.z);
+// @ts-ignore
+@lazy const UPPERCASE_LETTERS = new Range(Char.A, Char.Z);
+// @ts-ignore
+@lazy const UPPER_LOWER_OFFSET = Char.a - Char.A;
 
 export class CharacterRangeMatcher extends Matcher {
   private ranges: Range[];

assembly/nfa/nfa.ts

@@ -14,21 +14,15 @@ import {
 import { Char } from "../char";
 import { Matcher } from "./matcher";
 import { Flags } from "../regexp";
-
-export enum MatchResult {
-  // a match has occurred - which is a signal to consume a character
-  Match,
-  // a match failed, abort this regex
-  Fail,
-  // this state doesn't preform a match
-  Ignore,
-}
-
-let _stateId: u32 = 0;
+import { MatchResult } from "./types";
 
 /* eslint @typescript-eslint/no-empty-function: ["error", { "allow": ["constructors", "methods"] }] */
 export class State {
-  constructor(public transitions: State[] = [], public id: u32 = _stateId++) {}
+  @lazy static _stateId: u32 = 0;
+  constructor(
+    public transitions: State[] = [],
+    public id: u32 = State._stateId++
+  ) {}
 
   matches(input: string, position: u32): MatchResult {
     return MatchResult.Ignore;
@@ -253,3 +247,5 @@ class AutomataFactor {
     }
   }
 }
+
+export { MatchResult } from "./types";

assembly/nfa/types.ts

@@ -0,0 +1,10 @@
+// @ts-ignore
+@lazy
+export enum MatchResult {
+  // a match has occurred - which is a signal to consume a character
+  Match,
+  // a match failed, abort this regex
+  Fail,
+  // this state doesn't preform a match
+  Ignore,
+}

assembly/parser/node.ts

@@ -15,13 +15,12 @@ export const enum NodeType {
   Group,
 }
 
-const emptyNodeArray = new Array<Node>();
-
 export abstract class Node {
+  @lazy static readonly emptyArray: Node[] = new Array<Node>();
   constructor(public type: NodeType) {}
 
   children(): Node[] {
-    return emptyNodeArray;
+    return Node.emptyArray;
   }
 
   abstract clone(): Node;
@@ -37,7 +36,7 @@ export class AST extends Node {
   }
 
   children(): Node[] {
-    return this.body != null ? [this.body as Node] : emptyNodeArray;
+    return this.body != null ? [this.body as Node] : Node.emptyArray;
   }
 
   clone(): Node {
@@ -210,17 +209,17 @@ export class AlternationNode extends Node {
   }
 }
 
-let _id = 0;
-
 export class GroupNode extends Node {
+  @lazy static _id: i32 = 0;
+
   constructor(
     public expression: Node,
     public capturing: bool,
     public id: i32 = -1
   ) {
     super(NodeType.Group);
     if (id == -1) {
-      this.id = _id++;
+      this.id = GroupNode._id++;
     }
   }
 

assembly/parser/walker.ts

@@ -34,10 +34,13 @@ export function walker(ast: AST, visitor: (node: NodeVisitor) => void): void {
   }
 }
 
-// range quantifiers are implemented via 'expansion', which significantly
-// increases the size of the AST. This imposes a hard limit to prevent
-// memory-related issues
-const QUANTIFIER_LIMIT = 1000;
+/**
+ range quantifiers are implemented via 'expansion', which significantly 
+ increases the size of the AST. This imposes a hard limit to prevent 
+ memory-related issues
+*/
+// @ts-ignore
+@lazy const QUANTIFIER_LIMIT = 1000;
 
 function parentAsConcatNode(visitor: NodeVisitor): ConcatenationNode {
   let concatNode: ConcatenationNode | null = null;

assembly/regexp.ts

@@ -69,8 +69,6 @@ export class Match {
   }
 }
 
-let gm = new Array<GroupStartMarkerState>();
-
 export class Flags {
   global: bool = false;
   ignoreCase: bool = false;
@@ -112,6 +110,7 @@ function lastCapturesForGroup(groupMarkers: GroupStartMarkerState[]): string[] {
 }
 
 export class RegExp {
+  @lazy static gm: GroupStartMarkerState[] = new Array<GroupStartMarkerState>();
   lastIndex: i32 = 0;
   private flags: Flags;
   private nfa: Automata;
@@ -136,16 +135,16 @@ export class RegExp {
     this.nfa = Automata.toNFA(ast, flags);
 
     // find all the group marker states
-    gm = new Array<GroupStartMarkerState>();
+    RegExp.gm = new Array<GroupStartMarkerState>();
     nfaWalker(this.nfa.start, (state) => {
       if (state instanceof GroupStartMarkerState) {
         const startMarker = state as GroupStartMarkerState;
         if (startMarker.capturing) {
-          gm.push(state as GroupStartMarkerState);
+          RegExp.gm.push(state as GroupStartMarkerState);
         }
       }
     });
-    this.groupMarkers = gm;
+    this.groupMarkers = RegExp.gm;
 
     this.flags = flags;
   }