fix: provide better parser error handling for mathrm in expression

src/cells/MathField.ts

@@ -1,4 +1,4 @@
-import type { SvelteComponent } from "svelte";
+import type MathFieldElement from "../MathField.svelte";
 
 import { parseLatex } from "../parser/LatexToSympy";
 import type { Statement, FieldTypes, DataTableInfo } from "../parser/types";
@@ -12,7 +12,7 @@ export class MathField {
   parsingError = true;
   parsingErrorMessage = "Invalid Syntax";
   statement: Statement | null = null;
-  element: SvelteComponent | null = null;
+  element: MathFieldElement | null = null;
   pendingNewLatex = false;
   newLatex:string;
 
@@ -25,7 +25,7 @@ export class MathField {
   setPendingLatex(): void {
     if (this.pendingNewLatex && this.element) {
       this.element.setLatex(this.newLatex, false);
-      this.pendingNewLatex = false;
+      this.pendingNewLatex = false; // needed to prevent the unlikely scenario where an immediateUpdate leads to an infinite loop
     }
   }
 
@@ -39,5 +39,14 @@ export class MathField {
     this.parsingError = result.parsingError;
     this.parsingErrorMessage = result.parsingErrorMessage;
     this.statement = result.statement;
+
+    if (result.immediateUpdate && this.element) {
+      let startingPosition = this.element.getMathField().position;
+      this.setPendingLatex();
+      if (startingPosition > this.element.getMathField().lastOffset) {
+        startingPosition = this.element.getMathField().lastOffset;
+      }
+      this.element.getMathField().position = startingPosition;
+    }
   }
 }

src/parser/LatexLexer.g4

@@ -81,6 +81,7 @@ LTE: '\\le';
 GTE: '\\ge';
 
 COMMA: ',';
+DECIMAL_POINT: '.';
 
 CARET_SINGLE_CHAR_NUMBER: '^' [0-9];
 CARET_SINGLE_CHAR_ID: '^' [a-zA-Z];

src/parser/LatexParser.g4

@@ -125,7 +125,8 @@ expr: <assoc=right> id CARET_SINGLE_CHAR_ID_UNDERSCORE_SUBSCRIPT            #exp
     | expr integral_cmd                                                     #missingMultiplication
     | expr derivative_cmd                                                   #missingMultiplication
     | expr n_derivative_cmd                                                 #missingMultiplication
-    | CMD_PLACEHOLDER (L_BRACE R_BRACE)?                                    #emptyPlaceholder                
+    | CMD_PLACEHOLDER (L_BRACE R_BRACE)?                                    #emptyPlaceholder
+    | (CMD_MATHRM L_BRACE expr R_BRACE)? (DECIMAL_POINT | number)? CMD_MATHRM L_BRACE expr R_BRACE (DECIMAL_POINT | number)? #removeOperatorFont
     ;