First commit.

Signed-off-by: Chen Xiao <abigwc@gmail.com>

client/node_modules/katex/src/defineMacro.ts

@@ -0,0 +1,124 @@
+
+import {Token} from "./Token";
+import type Namespace from "./Namespace";
+import type {Mode} from "./types";
+
+/**
+ * Provides context to macros defined by functions. Implemented by
+ * MacroExpander.
+ */
+export interface MacroContextInterface {
+    mode: Mode;
+
+    /**
+     * Object mapping macros to their expansions.
+     */
+    macros: Namespace<MacroDefinition>;
+
+    /**
+     * Returns the topmost token on the stack, without expanding it.
+     * Similar in behavior to TeX's `\futurelet`.
+     */
+    future(): Token;
+
+    /**
+     * Remove and return the next unexpanded token.
+     */
+    popToken(): Token;
+
+    /**
+     * Consume all following space tokens, without expansion.
+     */
+    consumeSpaces(): void;
+
+    /**
+     * Expand the next token only once if possible.
+     */
+    expandOnce(expandableOnly?: boolean): number | boolean;
+
+    /**
+     * Expand the next token only once (if possible), and return the resulting
+     * top token on the stack (without removing anything from the stack).
+     * Similar in behavior to TeX's `\expandafter\futurelet`.
+     */
+    expandAfterFuture(): Token;
+
+    /**
+     * Recursively expand first token, then return first non-expandable token.
+     */
+    expandNextToken(): Token;
+
+    /**
+     * Fully expand the given macro name and return the resulting list of
+     * tokens, or return `undefined` if no such macro is defined.
+     */
+    expandMacro(name: string): Token[] | undefined;
+
+    /**
+     * Fully expand the given macro name and return the result as a string,
+     * or return `undefined` if no such macro is defined.
+     */
+    expandMacroAsText(name: string): string | undefined;
+
+    /**
+     * Fully expand the given token stream and return the resulting list of
+     * tokens.  Note that the input tokens are in reverse order, but the
+     * output tokens are in forward order.
+     */
+    expandTokens(tokens: Token[]): Token[];
+
+    /**
+     * Consume an argument from the token stream, and return the resulting array
+     * of tokens and start/end token.
+     */
+    consumeArg(delims?: string[] | null | undefined): MacroArg;
+
+    /**
+     * Consume the specified number of arguments from the token stream,
+     * and return the resulting array of arguments.
+     */
+    consumeArgs(numArgs: number): Token[][];
+
+    /**
+     * Determine whether a command is currently "defined" (has some
+     * functionality), meaning that it's a macro (in the current group),
+     * a function, a symbol, or one of the special commands listed in
+     * `implicitCommands`.
+     */
+    isDefined(name: string): boolean;
+
+    /**
+     * Determine whether a command is expandable.
+     */
+    isExpandable(name: string): boolean;
+}
+
+export type MacroArg = {
+    tokens: Token[];
+    start: Token;
+    end: Token;
+};
+
+/** Macro tokens (in reverse order). */
+export type MacroExpansion = {
+    tokens: Token[];
+    numArgs: number;
+    delimiters?: string[][];
+    unexpandable?: boolean; // used in \let
+};
+
+export type MacroDefinition = string | MacroExpansion |
+    ((arg0: MacroContextInterface) => string | MacroExpansion);
+export type MacroMap = Record<string, MacroDefinition>;
+
+/**
+ * All registered global/built-in macros.
+ * `macros.js` exports this same dictionary again and makes it public.
+ * `Parser.js` requires this dictionary via `macros.js`.
+ */
+export const _macros: MacroMap = {};
+
+// This function might one day accept an additional argument and do more things.
+export default function defineMacro(name: string, body: MacroDefinition) {
+    _macros[name] = body;
+}