Method parseArguments

src/Parser.ts:518–557

* Parses the arguments of a function or environment

(
        func: string,   // Should look like "\name" or "\begin{name}".
        funcData: FunctionSpec<NodeType> | EnvSpec<NodeType>,
    )

     * Parses the arguments of a function or environment
     */
    parseArguments(
        func: string,   // Should look like "\name" or "\begin{name}".
        funcData: FunctionSpec<NodeType> | EnvSpec<NodeType>,
    ): {
        args: AnyParseNode[];
        optArgs: (AnyParseNode | null)[];
    } {
        const numOptionalArgs = funcData.numOptionalArgs ?? 0;
        const totalArgs = funcData.numArgs + numOptionalArgs;
        if (totalArgs === 0) {
            return {args: [], optArgs: []};
        }

        const args: AnyParseNode[] = [];
        const optArgs: (AnyParseNode | null)[] = [];

        for (let i = 0; i < totalArgs; i++) {
            let argType = funcData.argTypes?.[i];
            const isOptional = i < numOptionalArgs;

            if (("primitive" in funcData && funcData.primitive && argType == null) ||
                // \sqrt expands into primitive if optional argument doesn't exist
                (funcData.type === "sqrt" && i === 1 && optArgs[0] == null)
            ) {
                argType = "primitive";
            }

            const arg = this.parseGroupOfType(`argument to '${func}'`,
                argType, isOptional);
            if (isOptional) {
                optArgs.push(arg);
            } else if (arg != null) {
                args.push(arg);
            } else { // should be unreachable
                throw new ParseError("Null argument, please report this as a bug");
            }
        }

        return {args, optArgs};
    }

    /**
     * Parses a group when the mode is changing.