AnPlusB.js•7.84 kB
import {
isDigit,
WhiteSpace,
Comment,
Ident,
Number,
Dimension
} from '../../tokenizer/index.js';
const PLUSSIGN = 0x002B; // U+002B PLUS SIGN (+)
const HYPHENMINUS = 0x002D; // U+002D HYPHEN-MINUS (-)
const N = 0x006E; // U+006E LATIN SMALL LETTER N (n)
const DISALLOW_SIGN = true;
const ALLOW_SIGN = false;
function checkInteger(offset, disallowSign) {
let pos = this.tokenStart + offset;
const code = this.charCodeAt(pos);
if (code === PLUSSIGN || code === HYPHENMINUS) {
if (disallowSign) {
this.error('Number sign is not allowed');
}
pos++;
}
for (; pos < this.tokenEnd; pos++) {
if (!isDigit(this.charCodeAt(pos))) {
this.error('Integer is expected', pos);
}
}
}
function checkTokenIsInteger(disallowSign) {
return checkInteger.call(this, 0, disallowSign);
}
function expectCharCode(offset, code) {
if (!this.cmpChar(this.tokenStart + offset, code)) {
let msg = '';
switch (code) {
case N:
msg = 'N is expected';
break;
case HYPHENMINUS:
msg = 'HyphenMinus is expected';
break;
}
this.error(msg, this.tokenStart + offset);
}
}
// ... <signed-integer>
// ... ['+' | '-'] <signless-integer>
function consumeB() {
let offset = 0;
let sign = 0;
let type = this.tokenType;
while (type === WhiteSpace || type === Comment) {
type = this.lookupType(++offset);
}
if (type !== Number) {
if (this.isDelim(PLUSSIGN, offset) ||
this.isDelim(HYPHENMINUS, offset)) {
sign = this.isDelim(PLUSSIGN, offset) ? PLUSSIGN : HYPHENMINUS;
do {
type = this.lookupType(++offset);
} while (type === WhiteSpace || type === Comment);
if (type !== Number) {
this.skip(offset);
checkTokenIsInteger.call(this, DISALLOW_SIGN);
}
} else {
return null;
}
}
if (offset > 0) {
this.skip(offset);
}
if (sign === 0) {
type = this.charCodeAt(this.tokenStart);
if (type !== PLUSSIGN && type !== HYPHENMINUS) {
this.error('Number sign is expected');
}
}
checkTokenIsInteger.call(this, sign !== 0);
return sign === HYPHENMINUS ? '-' + this.consume(Number) : this.consume(Number);
}
// An+B microsyntax https://www.w3.org/TR/css-syntax-3/#anb
export const name = 'AnPlusB';
export const structure = {
a: [String, null],
b: [String, null]
};
export function parse() {
/* eslint-disable brace-style*/
const start = this.tokenStart;
let a = null;
let b = null;
// <integer>
if (this.tokenType === Number) {
checkTokenIsInteger.call(this, ALLOW_SIGN);
b = this.consume(Number);
}
// -n
// -n <signed-integer>
// -n ['+' | '-'] <signless-integer>
// -n- <signless-integer>
// <dashndashdigit-ident>
else if (this.tokenType === Ident && this.cmpChar(this.tokenStart, HYPHENMINUS)) {
a = '-1';
expectCharCode.call(this, 1, N);
switch (this.tokenEnd - this.tokenStart) {
// -n
// -n <signed-integer>
// -n ['+' | '-'] <signless-integer>
case 2:
this.next();
b = consumeB.call(this);
break;
// -n- <signless-integer>
case 3:
expectCharCode.call(this, 2, HYPHENMINUS);
this.next();
this.skipSC();
checkTokenIsInteger.call(this, DISALLOW_SIGN);
b = '-' + this.consume(Number);
break;
// <dashndashdigit-ident>
default:
expectCharCode.call(this, 2, HYPHENMINUS);
checkInteger.call(this, 3, DISALLOW_SIGN);
this.next();
b = this.substrToCursor(start + 2);
}
}
// '+'? n
// '+'? n <signed-integer>
// '+'? n ['+' | '-'] <signless-integer>
// '+'? n- <signless-integer>
// '+'? <ndashdigit-ident>
else if (this.tokenType === Ident || (this.isDelim(PLUSSIGN) && this.lookupType(1) === Ident)) {
let sign = 0;
a = '1';
// just ignore a plus
if (this.isDelim(PLUSSIGN)) {
sign = 1;
this.next();
}
expectCharCode.call(this, 0, N);
switch (this.tokenEnd - this.tokenStart) {
// '+'? n
// '+'? n <signed-integer>
// '+'? n ['+' | '-'] <signless-integer>
case 1:
this.next();
b = consumeB.call(this);
break;
// '+'? n- <signless-integer>
case 2:
expectCharCode.call(this, 1, HYPHENMINUS);
this.next();
this.skipSC();
checkTokenIsInteger.call(this, DISALLOW_SIGN);
b = '-' + this.consume(Number);
break;
// '+'? <ndashdigit-ident>
default:
expectCharCode.call(this, 1, HYPHENMINUS);
checkInteger.call(this, 2, DISALLOW_SIGN);
this.next();
b = this.substrToCursor(start + sign + 1);
}
}
// <ndashdigit-dimension>
// <ndash-dimension> <signless-integer>
// <n-dimension>
// <n-dimension> <signed-integer>
// <n-dimension> ['+' | '-'] <signless-integer>
else if (this.tokenType === Dimension) {
const code = this.charCodeAt(this.tokenStart);
const sign = code === PLUSSIGN || code === HYPHENMINUS;
let i = this.tokenStart + sign;
for (; i < this.tokenEnd; i++) {
if (!isDigit(this.charCodeAt(i))) {
break;
}
}
if (i === this.tokenStart + sign) {
this.error('Integer is expected', this.tokenStart + sign);
}
expectCharCode.call(this, i - this.tokenStart, N);
a = this.substring(start, i);
// <n-dimension>
// <n-dimension> <signed-integer>
// <n-dimension> ['+' | '-'] <signless-integer>
if (i + 1 === this.tokenEnd) {
this.next();
b = consumeB.call(this);
} else {
expectCharCode.call(this, i - this.tokenStart + 1, HYPHENMINUS);
// <ndash-dimension> <signless-integer>
if (i + 2 === this.tokenEnd) {
this.next();
this.skipSC();
checkTokenIsInteger.call(this, DISALLOW_SIGN);
b = '-' + this.consume(Number);
}
// <ndashdigit-dimension>
else {
checkInteger.call(this, i - this.tokenStart + 2, DISALLOW_SIGN);
this.next();
b = this.substrToCursor(i + 1);
}
}
} else {
this.error();
}
if (a !== null && a.charCodeAt(0) === PLUSSIGN) {
a = a.substr(1);
}
if (b !== null && b.charCodeAt(0) === PLUSSIGN) {
b = b.substr(1);
}
return {
type: 'AnPlusB',
loc: this.getLocation(start, this.tokenStart),
a,
b
};
}
export function generate(node) {
if (node.a) {
const a =
node.a === '+1' && 'n' ||
node.a === '1' && 'n' ||
node.a === '-1' && '-n' ||
node.a + 'n';
if (node.b) {
const b = node.b[0] === '-' || node.b[0] === '+'
? node.b
: '+' + node.b;
this.tokenize(a + b);
} else {
this.tokenize(a);
}
} else {
this.tokenize(node.b);
}
}