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// @flow
import defineFunction from "../defineFunction";
import ParseError from "../ParseError";
import {assertNodeType} from "../parseNode";
// \@char is an internal function that takes a grouped decimal argument like
// {123} and converts into symbol with code 123. It is used by the *macro*
// \char defined in macros.js.
defineFunction({
type: "textord",
names: ["\\@char"],
props: {
numArgs: 1,
allowedInText: true,
},
handler({parser}, args) {
const arg = assertNodeType(args[0], "ordgroup");
const group = arg.body;
let number = "";
for (let i = 0; i < group.length; i++) {
const node = assertNodeType(group[i], "textord");
number += node.text;
}
let code = parseInt(number);
let text;
if (isNaN(code)) {
throw new ParseError(`\\@char has non-numeric argument ${number}`);
// If we drop IE support, the following code could be replaced with
// text = String.fromCodePoint(code)
} else if (code < 0 || code >= 0x10ffff) {
throw new ParseError(`\\@char with invalid code point ${number}`);
} else if (code <= 0xffff) {
text = String.fromCharCode(code);
} else { // Astral code point; split into surrogate halves
code -= 0x10000;
text = String.fromCharCode((code >> 10) + 0xd800,
(code & 0x3ff) + 0xdc00);
}
return {
type: "textord",
mode: parser.mode,
text: text,
};
},
});
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