fix: Remove circular dependency

When bundling mathjax - you are warned that there is a circular
dependency:

```shell
code: CIRCULAR_DEPENDENCY, message: Circular dependency: node_modules/mathjax-full/js/input/tex/TexParser.js -> node_modules/mathjax-full/js/input/tex/ParseUtil.js -> node_modules/mathjax-full/js/input/tex/TexParser.js
```

This can lead to runtime errors as the bundler has to guess which module
to define first.

This commit removes this circular dependency.

> Note: there are still other circular dependencies in place that should
also be fixed:

```shell

1) components/loader.js > components/package.js
2) input/tex/mathtools/MathtoolsConfiguration.js > input/tex/mathtools/MathtoolsMappings.js > input/tex/mathtools/MathtoolsMethods.js > input/tex/mathtools/MathtoolsUtil.js
3) input/tex/mathtools/MathtoolsMethods.js > input/tex/mathtools/MathtoolsUtil.js
4) output/svg.js > output/svg/WrapperFactory.js > output/svg/Wrappers.js > output/svg/Wrapper.js

```

Author: edeustace

ts/input/tex/ParseUtil.ts

@@ -31,87 +31,9 @@ import TexParser from './TexParser.js';
 import TexError from './TexError.js';
 import {entities} from '../../util/Entities.js';
 import {MmlMunderover} from '../../core/MmlTree/MmlNodes/munderover.js';
-
-
+import {Em} from '../../util/lengths.js';
 namespace ParseUtil {
 
-  // TODO (VS): Combine some of this with lengths in util.
-  const emPerInch = 7.2;
-  const pxPerInch = 72;
-  // Note, the following are TeX CM font values.
-  const UNIT_CASES: {[key: string]: ((m: number) => number)}  = {
-    'em': m => m,
-    'ex': m => m * .43,
-    'pt': m => m / 10,                    // 10 pt to an em
-    'pc': m => m * 1.2,                   // 12 pt to a pc
-    'px': m => m * emPerInch / pxPerInch,
-    'in': m => m * emPerInch,
-    'cm': m => m * emPerInch / 2.54, // 2.54 cm to an inch
-    'mm': m => m * emPerInch / 25.4, // 10 mm to a cm
-    'mu': m => m / 18,
-  };
-  const num = '([-+]?([.,]\\d+|\\d+([.,]\\d*)?))';
-  const unit = '(pt|em|ex|mu|px|mm|cm|in|pc)';
-  const dimenEnd = RegExp('^\\s*' + num + '\\s*' + unit + '\\s*$');
-  const dimenRest = RegExp('^\\s*' + num + '\\s*' + unit + ' ?');
-
-
-  /**
-   * Matches for a dimension argument.
-   * @param {string} dim The argument.
-   * @param {boolean} rest Allow for trailing garbage in the dimension string.
-   * @return {[string, string, number]} The match result as (Anglosaxon) value,
-   *     unit name, length of matched string. The latter is interesting in the
-   *     case of trailing garbage.
-   */
-  export function matchDimen(
-    dim: string, rest: boolean = false): [string, string, number] {
-      let match = dim.match(rest ? dimenRest : dimenEnd);
-      return match ?
-        muReplace([match[1].replace(/,/, '.'), match[4], match[0].length]) :
-        [null, null, 0];
-  }
-
-
-  /**
-   * Transforms mu dimension to em if necessary.
-   * @param {[string, string, number]} [value, unit, length] The dimension triple.
-   * @return {[string, string, number]} [value, unit, length] The transformed triple.
-   */
-  function muReplace([value, unit, length]: [string, string, number]): [string, string, number] {
-    if (unit !== 'mu') {
-      return [value, unit, length];
-    }
-    let em = Em(UNIT_CASES[unit](parseFloat(value || '1')));
-    return [em.slice(0, -2), 'em', length];
-  }
-
-
-  /**
-   * Convert a dimension string into standard em dimension.
-   * @param {string} dim The attribute string.
-   * @return {number} The numerical value.
-   */
-  export function dimen2em(dim: string): number {
-    let [value, unit] = matchDimen(dim);
-    let m = parseFloat(value || '1');
-    let func = UNIT_CASES[unit];
-    return func ? func(m) : 0;
-  }
-
-
-  /**
-   * Turns a number into an em value.
-   * @param {number} m The number.
-   * @return {string} The em dimension string.
-   */
-  export function Em(m: number): string {
-    if (Math.abs(m) < .0006) {
-      return '0em';
-    }
-    return m.toFixed(3).replace(/\.?0+$/, '') + 'em';
-  }
-
 
   /**
    * Takes an array of numbers and returns a space-separated string of em values.

ts/input/tex/TexParser.ts

@@ -23,7 +23,6 @@
  * @author [email protected] (Volker Sorge)
  */
 
-import ParseUtil from './ParseUtil.js';
 import {HandlerType} from './MapHandler.js';
 import Stack from './Stack.js';
 import StackItemFactory from './StackItemFactory.js';
@@ -35,6 +34,8 @@ import ParseOptions from './ParseOptions.js';
 import {StackItem, EnvList} from './StackItem.js';
 import {Symbol} from './Symbol.js';
 import {OptionList} from '../../util/Options.js';
+import {matchDimen} from '../../util/lengths.js';
+import {trimSpaces} from '../../util/string.js';
 
 
 /**
@@ -392,15 +393,15 @@ export default class TexParser {
   public GetDimen(name: string): string {
     if (this.GetNext() === '{') {
       let dimen = this.GetArgument(name);
-      let [value, unit] = ParseUtil.matchDimen(dimen);
+      let [value, unit] = matchDimen(dimen);
       if (value) {
         // @test Raise In Line, Lower 2, (Raise|Lower) Negative
         return value + unit;
       }
     } else {
       // @test Above, Raise, Lower, Modulo, Above With Delims
       let dimen = this.string.slice(this.i);
-      let [value, unit, length] = ParseUtil.matchDimen(dimen, true);
+      let [value, unit, length] = matchDimen(dimen, true);
       if (value) {
         this.i += length;
         return value + unit;
@@ -475,7 +476,7 @@ export default class TexParser {
    * @return {string} The delimiter.
    */
   public GetDelimiterArg(name: string): string {
-    let c = ParseUtil.trimSpaces(this.GetArgument(name));
+    let c = trimSpaces(this.GetArgument(name));
     if (c === '') {
       return null;
     }

ts/input/tex/ams/AmsMethods.ts

@@ -37,6 +37,7 @@ import {FlalignItem} from './AmsItems.js';
 import BaseMethods from '../base/BaseMethods.js';
 import {TEXCLASS} from '../../../core/MmlTree/MmlNode.js';
 import {MmlMunderover} from '../../../core/MmlTree/MmlNodes/munderover.js';
+import {Em} from '../../../util/lengths.js';
 
 
 // Namespace
@@ -289,7 +290,7 @@ AmsMethods.MultiIntegral = function(parser: TexParser, name: string,
  */
 AmsMethods.xArrow = function(parser: TexParser, name: string,
                              chr: number, l: number, r: number) {
-  let def = {width: '+' + ParseUtil.Em((l + r) / 18), lspace: ParseUtil.Em(l / 18)};
+  let def = {width: '+' + Em((l + r) / 18), lspace: Em(l / 18)};
   let bot = parser.GetBrackets(name);
   let first = parser.ParseArg(name);
   let dstrut = parser.create('node', 'mspace', [], {depth: '.25em'});

ts/input/tex/base/BaseItems.ts

@@ -34,6 +34,7 @@ import NodeUtil from '../NodeUtil.js';
 import {Property} from '../../../core/Tree/Node.js';
 import StackItemFactory from '../StackItemFactory.js';
 import {CheckType, BaseItem, StackItem, EnvList} from '../StackItem.js';
+import { dimen2em, Em } from '../../../util/lengths.js';
 
 
 /**
@@ -1082,15 +1083,15 @@ export class ArrayItem extends BaseItem {
       const rows = (this.arraydef['rowspacing'] as string).split(/ /);
       if (!this.getProperty('rowspacing')) {
         // @test Array Custom Linebreak
-        let dimem = ParseUtil.dimen2em(rows[0]);
+        let dimem = dimen2em(rows[0]);
         this.setProperty('rowspacing', dimem);
       }
       const rowspacing = this.getProperty('rowspacing') as number;
       while (rows.length < this.table.length) {
-        rows.push(ParseUtil.Em(rowspacing));
+        rows.push(Em(rowspacing));
       }
-      rows[this.table.length - 1] = ParseUtil.Em(
-        Math.max(0, rowspacing + ParseUtil.dimen2em(spacing)));
+      rows[this.table.length - 1] = Em(
+        Math.max(0, rowspacing + dimen2em(spacing)));
       this.arraydef['rowspacing'] = rows.join(' ');
     }
   }

ts/input/tex/base/BaseMethods.ts

@@ -35,7 +35,7 @@ import {MmlNode, TEXCLASS} from '../../../core/MmlTree/MmlNode.js';
 import {MmlMsubsup} from '../../../core/MmlTree/MmlNodes/msubsup.js';
 import {MmlMunderover} from '../../../core/MmlTree/MmlNodes/munderover.js';
 import {Label} from '../Tags.js';
-import {em} from '../../../util/lengths.js';
+import {em, matchDimen} from '../../../util/lengths.js';
 import {entities} from '../../../util/Entities.js';
 import {lookup} from '../../../util/Options.js';
 
@@ -1239,7 +1239,7 @@ BaseMethods.CrLaTeX = function(parser: TexParser, name: string, nobrackets: bool
     }
     if (parser.string.charAt(parser.i) === '[') {
       let dim = parser.GetBrackets(name, '');
-      let [value, unit, ] = ParseUtil.matchDimen(dim);
+      let [value, unit, ] = matchDimen(dim);
       // @test Custom Linebreak
       if (dim && !value) {
         // @test Dimension Error

ts/input/tex/bussproofs/BussproofsUtil.ts

@@ -25,12 +25,12 @@
 
 import ParseOptions from '../ParseOptions.js';
 import NodeUtil from '../NodeUtil.js';
-import ParseUtil from '../ParseUtil.js';
 
 import {MmlNode} from '../../../core/MmlTree/MmlNode.js';
 import {Property} from '../../../core/Tree/Node.js';
 import {MathItem} from '../../../core/MathItem.js';
 import {MathDocument} from '../../../core/MathDocument.js';
+import {dimen2em, Em} from '../../../util/lengths.js';
 
 
 type MATHITEM = MathItem<any, any, any>;
@@ -270,12 +270,12 @@ let addSpace = function(config: ParseOptions, inf: MmlNode,
   if (NodeUtil.isType(mspace, 'mspace')) {
     NodeUtil.setAttribute(
       mspace, 'width',
-      ParseUtil.Em(ParseUtil.dimen2em(
+      Em(dimen2em(
         NodeUtil.getAttribute(mspace, 'width') as string) + space));
     return;
   }
   mspace = config.nodeFactory.create('node', 'mspace', [],
-                                     {width: ParseUtil.Em(space)});
+                                     {width: Em(space)});
   if (right) {
     inf.appendChild(mspace);
     return;
@@ -362,7 +362,7 @@ let adjustSequents = function(config: ParseOptions) {
 const addSequentSpace = function(config: ParseOptions, sequent: MmlNode,
                                  position: number, direction: string, width: number) {
   let mspace = config.nodeFactory.create('node', 'mspace', [],
-                                         {width: ParseUtil.Em(width)});
+                                         {width: Em(width)});
   if (direction === 'left') {
     let row = sequent.childNodes[position].childNodes[0] as MmlNode;
     mspace.parent = row;

ts/input/tex/mathtools/MathtoolsMethods.ts

@@ -32,7 +32,7 @@ import TexParser from '../TexParser.js';
 import TexError from '../TexError.js';
 import NodeUtil from '../NodeUtil.js';
 import {TEXCLASS} from '../../../core/MmlTree/MmlNode.js';
-import {length2em, em} from '../../../util/lengths.js';
+import {length2em, em, Em} from '../../../util/lengths.js';
 import {lookup} from '../../../util/Options.js';
 import NewcommandUtil from '../newcommand/NewcommandUtil.js';
 import NewcommandMethods from '../newcommand/NewcommandMethods.js';
@@ -74,7 +74,7 @@ export const MathtoolsMethods: Record<string, ParseMethod> = {
       align = parser.GetBrackets(`\\begin{${begin.getName()}}`, parser.options.mathtools['smallmatrix-align']);
     }
     return MathtoolsMethods.Array(
-      parser, begin, open, close, align, ParseUtil.Em(1 / 3), '.2em', 'S', 1
+      parser, begin, open, close, align, Em(1 / 3), '.2em', 'S', 1
     );
   },
 

ts/input/tex/mathtools/MathtoolsUtil.ts

@@ -32,6 +32,7 @@ import {MmlNode} from '../../../core/MmlTree/MmlNode.js';
 
 import {MathtoolsMethods} from './MathtoolsMethods.js';
 import {PAIREDDELIMS} from './MathtoolsConfiguration.js';
+import { dimen2em, Em } from '../../../util/lengths.js';
 
 /**
  * Utility functions for the Mathtools package.
@@ -98,10 +99,10 @@ export const MathtoolsUtil = {
     if (!mtable.isKind('mtable')) return;
     let rowspacing = mtable.attributes.get('rowspacing') as string;
     if (rowspacing) {
-      const add = ParseUtil.dimen2em(spread);
+      const add = dimen2em(spread);
       rowspacing = rowspacing
         .split(/ /)
-        .map(s => ParseUtil.Em(Math.max(0, ParseUtil.dimen2em(s) + add)))
+        .map(s => Em(Math.max(0, dimen2em(s) + add)))
         .join(' ');
     } else {
       rowspacing = spread;

ts/util/lengths.ts

@@ -155,3 +155,78 @@ export function px(m: number, M: number = -BIGDIMEN, em: number = 16): string {
   if (Math.abs(m) < .1) return '0';
   return m.toFixed(1).replace(/\.0$/, '') + 'px';
 }
+
+// TODO (VS): Combine some of this with lengths in util.
+const emPerInch = 7.2;
+const pxPerInch = 72;
+// Note, the following are TeX CM font values.
+const UNIT_CASES: { [key: string]: (m: number) => number } = {
+  em: (m) => m,
+  ex: (m) => m * 0.43,
+  pt: (m) => m / 10, // 10 pt to an em
+  pc: (m) => m * 1.2, // 12 pt to a pc
+  px: (m) => (m * emPerInch) / pxPerInch,
+  in: (m) => m * emPerInch,
+  cm: (m) => (m * emPerInch) / 2.54, // 2.54 cm to an inch
+  mm: (m) => (m * emPerInch) / 25.4, // 10 mm to a cm
+  mu: (m) => m / 18,
+};
+const num = '([-+]?([.,]\\d+|\\d+([.,]\\d*)?))';
+const unit = '(pt|em|ex|mu|px|mm|cm|in|pc)';
+const dimenEnd = RegExp('^\\s*' + num + '\\s*' + unit + '\\s*$');
+const dimenRest = RegExp('^\\s*' + num + '\\s*' + unit + ' ?');
+/**
+ * Matches for a dimension argument.
+ * @param {string} dim The argument.
+ * @param {boolean} rest Allow for trailing garbage in the dimension string.
+ * @return {[string, string, number]} The match result as (Anglosaxon) value,
+ *     unit name, length of matched string. The latter is interesting in the
+ *     case of trailing garbage.
+ */
+export function matchDimen(
+  dim: string,
+  rest: boolean = false
+): [string, string, number] {
+  let match = dim.match(rest ? dimenRest : dimenEnd);
+  return match
+    ? muReplace([match[1].replace(/,/, '.'), match[4], match[0].length])
+    : [null, null, 0];
+}
+/**
+ * Convert a dimension string into standard em dimension.
+ * @param {string} dim The attribute string.
+ * @return {number} The numerical value.
+ */
+export function dimen2em(dim: string): number {
+  let [value, unit] = matchDimen(dim);
+  let m = parseFloat(value || '1');
+  let func = UNIT_CASES[unit];
+  return func ? func(m) : 0;
+}
+/**
+ * Transforms mu dimension to em if necessary.
+ * @param {[string, string, number]} [value, unit, length] The dimension triple.
+ * @return {[string, string, number]} [value, unit, length] The transformed triple.
+ */
+function muReplace([value, unit, length]: [string, string, number]): [
+  string,
+  string,
+  number
+] {
+  if (unit !== 'mu') {
+    return [value, unit, length];
+  }
+  let em = Em(UNIT_CASES[unit](parseFloat(value || '1')));
+  return [em.slice(0, -2), 'em', length];
+}
+/**
+ * Turns a number into an em value.
+ * @param {number} m The number.
+ * @return {string} The em dimension string.
+ */
+export function Em(m: number): string {
+  if (Math.abs(m) < 0.0006) {
+    return '0em';
+  }
+  return m.toFixed(3).replace(/\.?0+$/, '') + 'em';
+}

ts/util/string.ts

@@ -82,3 +82,19 @@ export function isPercent(x: string): boolean {
 export function split(x: string): string[] {
   return x.trim().split(/\s+/);
 }
+
+/**
+ * Trim spaces from a string.
+ * @param {string} text The string to clean.
+ * @return {string} The string with leading and trailing whitespace removed.
+ */
+export function trimSpaces(text: string): string {
+  if (typeof text !== 'string') {
+    return text;
+  }
+  let TEXT = text.trim();
+  if (TEXT.match(/\\$/) && text.match(/ $/)) {
+    TEXT += ' ';
+  }
+  return TEXT;
+}