ui: rendering performance follow-up (#26097)

tools/ui/src/lib/constants/latex-protection.ts

@@ -28,6 +28,18 @@ export const LATEX_MATH_AND_CODE_PATTERN =
 /** Regex to capture the content of a $$...\\\\...$$ block (display-formula with line-break) */
 export const LATEX_LINEBREAK_REGEXP = /\$\$([\s\S]*?\\\\[\s\S]*?)\$\$/;
 
+/**
+ * Matches the unescaped `\[...\]` display-math delimiter and surrounding
+ * context so callers can insert line-breaks around the placeholder or convert
+ * to inline when the formula has a non-empty trailing context (e.g. a table
+ * cell that opens with `\[` and closes with content after `\]`).
+ *
+ * group 1: prefix before `\[`
+ * group 2: formula body
+ * group 3: trailing context after `\]`
+ */
+export const LATEX_DISPLAY_BLOCK_REGEXP = /([\S].*?)\\\[([\s\S]*?)\\\](.*)/g;
+
 /**
  * Cheap gate for `preprocessLaTeX`. Every transformation it performs is triggered
  * by a `$` (inline/display math, currency escaping) or a backslash escape
@@ -36,6 +48,76 @@ export const LATEX_LINEBREAK_REGEXP = /\$\$([\s\S]*?\\\\[\s\S]*?)\$\$/;
  */
 export const LATEX_TRIGGER_REGEXP = /[$\\]/;
 
+/** Inline LaTeX math delimiter (the dollar sign). */
+export const LATEX_INLINE_DELIMITER = '$';
+
+/** Display LaTeX math delimiter (paired dollar signs). */
+export const LATEX_DISPLAY_DELIMITER = '$$';
+
+/** Matches a single non-whitespace character. */
+export const LATEX_NON_WHITESPACE_REGEXP = /\S/;
+
+/** Matches a character that may appear adjacent to `$`, indicating a non-TeX
+ * context such as an identifier (`var$`, `$var`), currency ($5), or code. */
+export const LATEX_NEIGHBOR_CHAR_REGEXP = /[A-Za-z0-9_$-]/;
+
+/** Matches a single digit (used to detect currency-like `$5`). */
+export const LATEX_DIGIT_REGEXP = /[0-9]/;
+
+/** Matches the leading blockquote prefix (`> ` or `>`) on a markdown line. */
+export const LATEX_BLOCKQUOTE_PREFIX_REGEXP = /^(>\s*)/;
+
+/** Matches the placeholder inserted by the protect/restore pipeline for a
+ * protected LaTeX expression. Group 1 is the index into `latexExpressions`. */
+export const LATEX_PLACEHOLDER_REGEXP = /<<LATEX_(\d+)>>/g;
+
+/** Matches the placeholder inserted by the protect/restore pipeline for a
+ * protected code block. Group 1 is the index into `codeBlocks`. */
+export const CODE_BLOCK_PLACEHOLDER_REGEXP = /<<CODE_BLOCK_(\d+)>>/g;
+
+/** Matches a `$` immediately followed by a digit, which is treated as a
+ * currency amount (e.g. `$5`) and escaped to `\$5` so it isn't parsed as math. */
+export const LATEX_CURRENCY_DOLLAR_REGEXP = /\$(?=\d)/g;
+
+/** Captures remaining `$$...$$`, `\[...\]`, `\(...\)` (only unescaped via
+ * `(?<!\\)`) after the display-block pass has run. Group 1 holds the
+ * matched formula. */
+export const LATEX_PROTECT_REGEXP =
+	/(\$\$[\s\S]*?\$\$|(?<!\\)\\\[[\s\S]*?\\\]|(?<!\\)\\\(.*?\\\))/g;
+
+/** Matches unescaped inline `\(...\)` (at least one char inside) used to
+ * convert `\(` → `$` after the protect pass. */
+export const LATEX_INLINE_CONVERT_REGEXP = /(?<!\\)\\\((.+?)\\\)/g;
+
+/** Matches unescaped display `\[...\]` used to convert `\[` → `$$`
+ * after the protect pass. */
+export const LATEX_DISPLAY_CONVERT_REGEXP = /(?<!\\)\\\[([\s\S]*?)\\\]/g;
+
+/** `\(` — opens an inline LaTeX math block. */
+export const LATEX_INLINE_OPEN = '\\(';
+
+/** `\)` — closes an inline LaTeX math block. */
+export const LATEX_INLINE_CLOSE = '\\)';
+
+/** `\[` — opens a display LaTeX math block. */
+export const LATEX_DISPLAY_OPEN = '\\[';
+
+/** `\]` — closes a display LaTeX math block. */
+export const LATEX_DISPLAY_CLOSE = '\\]';
+
+/** `\` — the LaTeX escape character. */
+export const LATEX_BACKSLASH = '\\';
+
+/** `\$` — dollar sign escaped so it isn't parsed as math (used to disambiguate
+ * currency amounts like `$5`). */
+export const LATEX_CURRENCY_ESCAPE = '\\$';
+
+/** `\ce{` — mhchem chemistry command prefix. */
+export const LATEX_MHCHEM_CE = '\\ce{';
+
+/** `\pu{` — mhchem physics-unit command prefix. */
+export const LATEX_MHCHEM_PU = '\\pu{';
+
 /** map from mchem-regexp to replacement */
 export const MHCHEM_PATTERN_MAP: readonly [RegExp, string][] = [
 	[/(\s)\$\\ce{/g, '$1$\\\\ce{'],