less
Version:
Leaner CSS
1,265 lines (1,096 loc) • 72.3 kB
JavaScript
var LessError = require('../less-error'),
tree = require("../tree"),
visitors = require("../visitors"),
getParserInput = require("./parser-input"),
utils = require("../utils");
//
// less.js - parser
//
// A relatively straight-forward predictive parser.
// There is no tokenization/lexing stage, the input is parsed
// in one sweep.
//
// To make the parser fast enough to run in the browser, several
// optimization had to be made:
//
// - Matching and slicing on a huge input is often cause of slowdowns.
// The solution is to chunkify the input into smaller strings.
// The chunks are stored in the `chunks` var,
// `j` holds the current chunk index, and `currentPos` holds
// the index of the current chunk in relation to `input`.
// This gives us an almost 4x speed-up.
//
// - In many cases, we don't need to match individual tokens;
// for example, if a value doesn't hold any variables, operations
// or dynamic references, the parser can effectively 'skip' it,
// treating it as a literal.
// An example would be '1px solid #000' - which evaluates to itself,
// we don't need to know what the individual components are.
// The drawback, of course is that you don't get the benefits of
// syntax-checking on the CSS. This gives us a 50% speed-up in the parser,
// and a smaller speed-up in the code-gen.
//
//
// Token matching is done with the `$` function, which either takes
// a terminal string or regexp, or a non-terminal function to call.
// It also takes care of moving all the indices forwards.
//`
//
var Parser = function Parser(context, imports, fileInfo) {
var parsers,
parserInput = getParserInput();
function error(msg, type) {
throw new LessError(
{
index: parserInput.i,
filename: fileInfo.filename,
type: type || 'Syntax',
message: msg
},
imports
);
}
function expect(arg, msg, index) {
// some older browsers return typeof 'function' for RegExp
var result = (arg instanceof Function) ? arg.call(parsers) : parserInput.$re(arg);
if (result) {
return result;
}
error(msg || (typeof arg === 'string' ? "expected '" + arg + "' got '" + parserInput.currentChar() + "'"
: "unexpected token"));
}
// Specialization of expect()
function expectChar(arg, msg) {
if (parserInput.$char(arg)) {
return arg;
}
error(msg || "expected '" + arg + "' got '" + parserInput.currentChar() + "'");
}
function getDebugInfo(index) {
var filename = fileInfo.filename;
return {
lineNumber: utils.getLocation(index, parserInput.getInput()).line + 1,
fileName: filename
};
}
//
// The Parser
//
return {
//
// Parse an input string into an abstract syntax tree,
// @param str A string containing 'less' markup
// @param callback call `callback` when done.
// @param [additionalData] An optional map which can contains vars - a map (key, value) of variables to apply
//
parse: function (str, callback, additionalData) {
var root, error = null, globalVars, modifyVars, ignored, preText = "";
globalVars = (additionalData && additionalData.globalVars) ? Parser.serializeVars(additionalData.globalVars) + '\n' : '';
modifyVars = (additionalData && additionalData.modifyVars) ? '\n' + Parser.serializeVars(additionalData.modifyVars) : '';
if (context.pluginManager) {
var preProcessors = context.pluginManager.getPreProcessors();
for (var i = 0; i < preProcessors.length; i++) {
str = preProcessors[i].process(str, { context: context, imports: imports, fileInfo: fileInfo });
}
}
if (globalVars || (additionalData && additionalData.banner)) {
preText = ((additionalData && additionalData.banner) ? additionalData.banner : "") + globalVars;
ignored = imports.contentsIgnoredChars;
ignored[fileInfo.filename] = ignored[fileInfo.filename] || 0;
ignored[fileInfo.filename] += preText.length;
}
str = str.replace(/\r\n?/g, '\n');
// Remove potential UTF Byte Order Mark
str = preText + str.replace(/^\uFEFF/, '') + modifyVars;
imports.contents[fileInfo.filename] = str;
// Start with the primary rule.
// The whole syntax tree is held under a Ruleset node,
// with the `root` property set to true, so no `{}` are
// output. The callback is called when the input is parsed.
try {
parserInput.start(str, context.chunkInput, function fail(msg, index) {
throw new LessError({
index: index,
type: 'Parse',
message: msg,
filename: fileInfo.filename
}, imports);
});
root = new(tree.Ruleset)(null, this.parsers.primary());
root.root = true;
root.firstRoot = true;
} catch (e) {
return callback(new LessError(e, imports, fileInfo.filename));
}
// If `i` is smaller than the `input.length - 1`,
// it means the parser wasn't able to parse the whole
// string, so we've got a parsing error.
//
// We try to extract a \n delimited string,
// showing the line where the parse error occurred.
// We split it up into two parts (the part which parsed,
// and the part which didn't), so we can color them differently.
var endInfo = parserInput.end();
if (!endInfo.isFinished) {
var message = endInfo.furthestPossibleErrorMessage;
if (!message) {
message = "Unrecognised input";
if (endInfo.furthestChar === '}') {
message += ". Possibly missing opening '{'";
} else if (endInfo.furthestChar === ')') {
message += ". Possibly missing opening '('";
} else if (endInfo.furthestReachedEnd) {
message += ". Possibly missing something";
}
}
error = new LessError({
type: "Parse",
message: message,
index: endInfo.furthest,
filename: fileInfo.filename
}, imports);
}
var finish = function (e) {
e = error || e || imports.error;
if (e) {
if (!(e instanceof LessError)) {
e = new LessError(e, imports, fileInfo.filename);
}
return callback(e);
}
else {
return callback(null, root);
}
};
if (context.processImports !== false) {
new visitors.ImportVisitor(imports, finish)
.run(root);
} else {
return finish();
}
},
//
// Here in, the parsing rules/functions
//
// The basic structure of the syntax tree generated is as follows:
//
// Ruleset -> Rule -> Value -> Expression -> Entity
//
// Here's some Less code:
//
// .class {
// color: #fff;
// border: 1px solid #000;
// width: @w + 4px;
// > .child {...}
// }
//
// And here's what the parse tree might look like:
//
// Ruleset (Selector '.class', [
// Rule ("color", Value ([Expression [Color #fff]]))
// Rule ("border", Value ([Expression [Dimension 1px][Keyword "solid"][Color #000]]))
// Rule ("width", Value ([Expression [Operation " + " [Variable "@w"][Dimension 4px]]]))
// Ruleset (Selector [Element '>', '.child'], [...])
// ])
//
// In general, most rules will try to parse a token with the `$re()` function, and if the return
// value is truly, will return a new node, of the relevant type. Sometimes, we need to check
// first, before parsing, that's when we use `peek()`.
//
parsers: parsers = {
//
// The `primary` rule is the *entry* and *exit* point of the parser.
// The rules here can appear at any level of the parse tree.
//
// The recursive nature of the grammar is an interplay between the `block`
// rule, which represents `{ ... }`, the `ruleset` rule, and this `primary` rule,
// as represented by this simplified grammar:
//
// primary → (ruleset | rule)+
// ruleset → selector+ block
// block → '{' primary '}'
//
// Only at one point is the primary rule not called from the
// block rule: at the root level.
//
primary: function () {
var mixin = this.mixin, root = [], node;
while (true) {
while (true) {
node = this.comment();
if (!node) { break; }
root.push(node);
}
// always process comments before deciding if finished
if (parserInput.finished) {
break;
}
if (parserInput.peek('}')) {
break;
}
node = this.extendRule();
if (node) {
root = root.concat(node);
continue;
}
node = mixin.definition() || this.rule() || this.ruleset() ||
mixin.call() || this.rulesetCall() || this.entities.call() || this.directive();
if (node) {
root.push(node);
} else {
var foundSemiColon = false;
while (parserInput.$char(";")) {
foundSemiColon = true;
}
if (!foundSemiColon) {
break;
}
}
}
return root;
},
// comments are collected by the main parsing mechanism and then assigned to nodes
// where the current structure allows it
comment: function () {
if (parserInput.commentStore.length) {
var comment = parserInput.commentStore.shift();
return new(tree.Comment)(comment.text, comment.isLineComment, comment.index, fileInfo);
}
},
//
// Entities are tokens which can be found inside an Expression
//
entities: {
//
// A string, which supports escaping " and '
//
// "milky way" 'he\'s the one!'
//
quoted: function () {
var str, index = parserInput.i, isEscaped = false;
parserInput.save();
if (parserInput.$char("~")) {
isEscaped = true;
}
str = parserInput.$quoted();
if (!str) {
parserInput.restore();
return;
}
parserInput.forget();
return new(tree.Quoted)(str.charAt(0), str.substr(1, str.length - 2), isEscaped, index, fileInfo);
},
//
// A catch-all word, such as:
//
// black border-collapse
//
keyword: function () {
var k = parserInput.$char("%") || parserInput.$re(/^[_A-Za-z-][_A-Za-z0-9-]*/);
if (k) {
return tree.Color.fromKeyword(k) || new(tree.Keyword)(k);
}
},
//
// A function call
//
// rgb(255, 0, 255)
//
// We also try to catch IE's `alpha()`, but let the `alpha` parser
// deal with the details.
//
// The arguments are parsed with the `entities.arguments` parser.
//
call: function () {
var name, nameLC, args, alpha, index = parserInput.i;
// http://jsperf.com/case-insensitive-regex-vs-strtolower-then-regex/18
if (parserInput.peek(/^url\(/i)) {
return;
}
parserInput.save();
name = parserInput.$re(/^([\w-]+|%|progid:[\w\.]+)\(/);
if (!name) { parserInput.forget(); return; }
name = name[1];
nameLC = name.toLowerCase();
if (nameLC === 'alpha') {
alpha = parsers.alpha();
if (alpha) {
parserInput.forget();
return alpha;
}
}
args = this.arguments();
if (! parserInput.$char(')')) {
parserInput.restore("Could not parse call arguments or missing ')'");
return;
}
parserInput.forget();
return new(tree.Call)(name, args, index, fileInfo);
},
arguments: function () {
var argsSemiColon = [], argsComma = [],
expressions = [],
isSemiColonSeparated, value, arg;
parserInput.save();
while (true) {
arg = parsers.detachedRuleset() || this.assignment() || parsers.expression();
if (!arg) {
break;
}
value = arg;
if (arg.value && arg.value.length == 1) {
value = arg.value[0];
}
if (value) {
expressions.push(value);
}
argsComma.push(value);
if (parserInput.$char(',')) {
continue;
}
if (parserInput.$char(';') || isSemiColonSeparated) {
isSemiColonSeparated = true;
if (expressions.length > 1) {
value = new(tree.Value)(expressions);
}
argsSemiColon.push(value);
expressions = [];
}
}
parserInput.forget();
return isSemiColonSeparated ? argsSemiColon : argsComma;
},
literal: function () {
return this.dimension() ||
this.color() ||
this.quoted() ||
this.unicodeDescriptor();
},
// Assignments are argument entities for calls.
// They are present in ie filter properties as shown below.
//
// filter: progid:DXImageTransform.Microsoft.Alpha( *opacity=50* )
//
assignment: function () {
var key, value;
parserInput.save();
key = parserInput.$re(/^\w+(?=\s?=)/i);
if (!key) {
parserInput.restore();
return;
}
if (!parserInput.$char('=')) {
parserInput.restore();
return;
}
value = parsers.entity();
if (value) {
parserInput.forget();
return new(tree.Assignment)(key, value);
} else {
parserInput.restore();
}
},
//
// Parse url() tokens
//
// We use a specific rule for urls, because they don't really behave like
// standard function calls. The difference is that the argument doesn't have
// to be enclosed within a string, so it can't be parsed as an Expression.
//
url: function () {
var value, index = parserInput.i;
parserInput.autoCommentAbsorb = false;
if (!parserInput.$str("url(")) {
parserInput.autoCommentAbsorb = true;
return;
}
value = this.quoted() || this.variable() ||
parserInput.$re(/^(?:(?:\\[\(\)'"])|[^\(\)'"])+/) || "";
parserInput.autoCommentAbsorb = true;
expectChar(')');
return new(tree.URL)((value.value != null || value instanceof tree.Variable) ?
value : new(tree.Anonymous)(value), index, fileInfo);
},
//
// A Variable entity, such as `@fink`, in
//
// width: @fink + 2px
//
// We use a different parser for variable definitions,
// see `parsers.variable`.
//
variable: function () {
var name, index = parserInput.i;
if (parserInput.currentChar() === '@' && (name = parserInput.$re(/^@@?[\w-]+/))) {
return new(tree.Variable)(name, index, fileInfo);
}
},
// A variable entity using the protective {} e.g. @{var}
variableCurly: function () {
var curly, index = parserInput.i;
if (parserInput.currentChar() === '@' && (curly = parserInput.$re(/^@\{([\w-]+)\}/))) {
return new(tree.Variable)("@" + curly[1], index, fileInfo);
}
},
//
// A Hexadecimal color
//
// #4F3C2F
//
// `rgb` and `hsl` colors are parsed through the `entities.call` parser.
//
color: function () {
var rgb;
if (parserInput.currentChar() === '#' && (rgb = parserInput.$re(/^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})/))) {
// strip colons, brackets, whitespaces and other characters that should not
// definitely be part of color string
var colorCandidateString = rgb.input.match(/^#([\w]+).*/);
colorCandidateString = colorCandidateString[1];
if (!colorCandidateString.match(/^[A-Fa-f0-9]+$/)) { // verify if candidate consists only of allowed HEX characters
error("Invalid HEX color code");
}
return new(tree.Color)(rgb[1], undefined, '#' + colorCandidateString);
}
},
colorKeyword: function () {
parserInput.save();
var autoCommentAbsorb = parserInput.autoCommentAbsorb;
parserInput.autoCommentAbsorb = false;
var k = parserInput.$re(/^[_A-Za-z-][_A-Za-z0-9-]+/);
parserInput.autoCommentAbsorb = autoCommentAbsorb;
if (!k) {
parserInput.forget();
return;
}
parserInput.restore();
var color = tree.Color.fromKeyword(k);
if (color) {
parserInput.$str(k);
return color;
}
},
//
// A Dimension, that is, a number and a unit
//
// 0.5em 95%
//
dimension: function () {
if (parserInput.peekNotNumeric()) {
return;
}
var value = parserInput.$re(/^([+-]?\d*\.?\d+)(%|[a-z_]+)?/i);
if (value) {
return new(tree.Dimension)(value[1], value[2]);
}
},
//
// A unicode descriptor, as is used in unicode-range
//
// U+0?? or U+00A1-00A9
//
unicodeDescriptor: function () {
var ud;
ud = parserInput.$re(/^U\+[0-9a-fA-F?]+(\-[0-9a-fA-F?]+)?/);
if (ud) {
return new(tree.UnicodeDescriptor)(ud[0]);
}
},
//
// JavaScript code to be evaluated
//
// `window.location.href`
//
javascript: function () {
var js, index = parserInput.i;
parserInput.save();
var escape = parserInput.$char("~");
var jsQuote = parserInput.$char("`");
if (!jsQuote) {
parserInput.restore();
return;
}
js = parserInput.$re(/^[^`]*`/);
if (js) {
parserInput.forget();
return new(tree.JavaScript)(js.substr(0, js.length - 1), Boolean(escape), index, fileInfo);
}
parserInput.restore("invalid javascript definition");
}
},
//
// The variable part of a variable definition. Used in the `rule` parser
//
// @fink:
//
variable: function () {
var name;
if (parserInput.currentChar() === '@' && (name = parserInput.$re(/^(@[\w-]+)\s*:/))) { return name[1]; }
},
//
// The variable part of a variable definition. Used in the `rule` parser
//
// @fink();
//
rulesetCall: function () {
var name;
if (parserInput.currentChar() === '@' && (name = parserInput.$re(/^(@[\w-]+)\(\s*\)\s*;/))) {
return new tree.RulesetCall(name[1]);
}
},
//
// extend syntax - used to extend selectors
//
extend: function(isRule) {
var elements, e, index = parserInput.i, option, extendList, extend;
if (!parserInput.$str(isRule ? "&:extend(" : ":extend(")) {
return;
}
do {
option = null;
elements = null;
while (! (option = parserInput.$re(/^(all)(?=\s*(\)|,))/))) {
e = this.element();
if (!e) {
break;
}
if (elements) {
elements.push(e);
} else {
elements = [ e ];
}
}
option = option && option[1];
if (!elements) {
error("Missing target selector for :extend().");
}
extend = new(tree.Extend)(new(tree.Selector)(elements), option, index, fileInfo);
if (extendList) {
extendList.push(extend);
} else {
extendList = [ extend ];
}
} while (parserInput.$char(","));
expect(/^\)/);
if (isRule) {
expect(/^;/);
}
return extendList;
},
//
// extendRule - used in a rule to extend all the parent selectors
//
extendRule: function() {
return this.extend(true);
},
//
// Mixins
//
mixin: {
//
// A Mixin call, with an optional argument list
//
// #mixins > .square(#fff);
// .rounded(4px, black);
// .button;
//
// The `while` loop is there because mixins can be
// namespaced, but we only support the child and descendant
// selector for now.
//
call: function () {
var s = parserInput.currentChar(), important = false, index = parserInput.i, elemIndex,
elements, elem, e, c, args;
if (s !== '.' && s !== '#') { return; }
parserInput.save(); // stop us absorbing part of an invalid selector
while (true) {
elemIndex = parserInput.i;
e = parserInput.$re(/^[#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/);
if (!e) {
break;
}
elem = new(tree.Element)(c, e, elemIndex, fileInfo);
if (elements) {
elements.push(elem);
} else {
elements = [ elem ];
}
c = parserInput.$char('>');
}
if (elements) {
if (parserInput.$char('(')) {
args = this.args(true).args;
expectChar(')');
}
if (parsers.important()) {
important = true;
}
if (parsers.end()) {
parserInput.forget();
return new(tree.mixin.Call)(elements, args, index, fileInfo, important);
}
}
parserInput.restore();
},
args: function (isCall) {
var entities = parsers.entities,
returner = { args:null, variadic: false },
expressions = [], argsSemiColon = [], argsComma = [],
isSemiColonSeparated, expressionContainsNamed, name, nameLoop,
value, arg, expand;
parserInput.save();
while (true) {
if (isCall) {
arg = parsers.detachedRuleset() || parsers.expression();
} else {
parserInput.commentStore.length = 0;
if (parserInput.$str("...")) {
returner.variadic = true;
if (parserInput.$char(";") && !isSemiColonSeparated) {
isSemiColonSeparated = true;
}
(isSemiColonSeparated ? argsSemiColon : argsComma)
.push({ variadic: true });
break;
}
arg = entities.variable() || entities.literal() || entities.keyword();
}
if (!arg) {
break;
}
nameLoop = null;
if (arg.throwAwayComments) {
arg.throwAwayComments();
}
value = arg;
var val = null;
if (isCall) {
// Variable
if (arg.value && arg.value.length == 1) {
val = arg.value[0];
}
} else {
val = arg;
}
if (val && val instanceof tree.Variable) {
if (parserInput.$char(':')) {
if (expressions.length > 0) {
if (isSemiColonSeparated) {
error("Cannot mix ; and , as delimiter types");
}
expressionContainsNamed = true;
}
value = parsers.detachedRuleset() || parsers.expression();
if (!value) {
if (isCall) {
error("could not understand value for named argument");
} else {
parserInput.restore();
returner.args = [];
return returner;
}
}
nameLoop = (name = val.name);
} else if (parserInput.$str("...")) {
if (!isCall) {
returner.variadic = true;
if (parserInput.$char(";") && !isSemiColonSeparated) {
isSemiColonSeparated = true;
}
(isSemiColonSeparated ? argsSemiColon : argsComma)
.push({ name: arg.name, variadic: true });
break;
} else {
expand = true;
}
} else if (!isCall) {
name = nameLoop = val.name;
value = null;
}
}
if (value) {
expressions.push(value);
}
argsComma.push({ name:nameLoop, value:value, expand:expand });
if (parserInput.$char(',')) {
continue;
}
if (parserInput.$char(';') || isSemiColonSeparated) {
if (expressionContainsNamed) {
error("Cannot mix ; and , as delimiter types");
}
isSemiColonSeparated = true;
if (expressions.length > 1) {
value = new(tree.Value)(expressions);
}
argsSemiColon.push({ name:name, value:value, expand:expand });
name = null;
expressions = [];
expressionContainsNamed = false;
}
}
parserInput.forget();
returner.args = isSemiColonSeparated ? argsSemiColon : argsComma;
return returner;
},
//
// A Mixin definition, with a list of parameters
//
// .rounded (@radius: 2px, @color) {
// ...
// }
//
// Until we have a finer grained state-machine, we have to
// do a look-ahead, to make sure we don't have a mixin call.
// See the `rule` function for more information.
//
// We start by matching `.rounded (`, and then proceed on to
// the argument list, which has optional default values.
// We store the parameters in `params`, with a `value` key,
// if there is a value, such as in the case of `@radius`.
//
// Once we've got our params list, and a closing `)`, we parse
// the `{...}` block.
//
definition: function () {
var name, params = [], match, ruleset, cond, variadic = false;
if ((parserInput.currentChar() !== '.' && parserInput.currentChar() !== '#') ||
parserInput.peek(/^[^{]*\}/)) {
return;
}
parserInput.save();
match = parserInput.$re(/^([#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+)\s*\(/);
if (match) {
name = match[1];
var argInfo = this.args(false);
params = argInfo.args;
variadic = argInfo.variadic;
// .mixincall("@{a}");
// looks a bit like a mixin definition..
// also
// .mixincall(@a: {rule: set;});
// so we have to be nice and restore
if (!parserInput.$char(')')) {
parserInput.restore("Missing closing ')'");
return;
}
parserInput.commentStore.length = 0;
if (parserInput.$str("when")) { // Guard
cond = expect(parsers.conditions, 'expected condition');
}
ruleset = parsers.block();
if (ruleset) {
parserInput.forget();
return new(tree.mixin.Definition)(name, params, ruleset, cond, variadic);
} else {
parserInput.restore();
}
} else {
parserInput.forget();
}
}
},
//
// Entities are the smallest recognized token,
// and can be found inside a rule's value.
//
entity: function () {
var entities = this.entities;
return this.comment() || entities.literal() || entities.variable() || entities.url() ||
entities.call() || entities.keyword() || entities.javascript();
},
//
// A Rule terminator. Note that we use `peek()` to check for '}',
// because the `block` rule will be expecting it, but we still need to make sure
// it's there, if ';' was omitted.
//
end: function () {
return parserInput.$char(';') || parserInput.peek('}');
},
//
// IE's alpha function
//
// alpha(opacity=88)
//
alpha: function () {
var value;
// http://jsperf.com/case-insensitive-regex-vs-strtolower-then-regex/18
if (! parserInput.$re(/^opacity=/i)) { return; }
value = parserInput.$re(/^\d+/);
if (!value) {
value = expect(this.entities.variable, "Could not parse alpha");
}
expectChar(')');
return new(tree.Alpha)(value);
},
//
// A Selector Element
//
// div
// + h1
// #socks
// input[type="text"]
//
// Elements are the building blocks for Selectors,
// they are made out of a `Combinator` (see combinator rule),
// and an element name, such as a tag a class, or `*`.
//
element: function () {
var e, c, v, index = parserInput.i;
c = this.combinator();
e = parserInput.$re(/^(?:\d+\.\d+|\d+)%/) ||
parserInput.$re(/^(?:[.#]?|:*)(?:[\w-]|[^\x00-\x9f]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/) ||
parserInput.$char('*') || parserInput.$char('&') || this.attribute() ||
parserInput.$re(/^\([^&()@]+\)/) || parserInput.$re(/^[\.#:](?=@)/) ||
this.entities.variableCurly();
if (! e) {
parserInput.save();
if (parserInput.$char('(')) {
if ((v = this.selector()) && parserInput.$char(')')) {
e = new(tree.Paren)(v);
parserInput.forget();
} else {
parserInput.restore("Missing closing ')'");
}
} else {
parserInput.forget();
}
}
if (e) { return new(tree.Element)(c, e, index, fileInfo); }
},
//
// Combinators combine elements together, in a Selector.
//
// Because our parser isn't white-space sensitive, special care
// has to be taken, when parsing the descendant combinator, ` `,
// as it's an empty space. We have to check the previous character
// in the input, to see if it's a ` ` character. More info on how
// we deal with this in *combinator.js*.
//
combinator: function () {
var c = parserInput.currentChar();
if (c === '/') {
parserInput.save();
var slashedCombinator = parserInput.$re(/^\/[a-z]+\//i);
if (slashedCombinator) {
parserInput.forget();
return new(tree.Combinator)(slashedCombinator);
}
parserInput.restore();
}
if (c === '>' || c === '+' || c === '~' || c === '|' || c === '^') {
parserInput.i++;
if (c === '^' && parserInput.currentChar() === '^') {
c = '^^';
parserInput.i++;
}
while (parserInput.isWhitespace()) { parserInput.i++; }
return new(tree.Combinator)(c);
} else if (parserInput.isWhitespace(-1)) {
return new(tree.Combinator)(" ");
} else {
return new(tree.Combinator)(null);
}
},
//
// A CSS selector (see selector below)
// with less extensions e.g. the ability to extend and guard
//
lessSelector: function () {
return this.selector(true);
},
//
// A CSS Selector
//
// .class > div + h1
// li a:hover
//
// Selectors are made out of one or more Elements, see above.
//
selector: function (isLess) {
var index = parserInput.i, elements, extendList, c, e, allExtends, when, condition;
while ((isLess && (extendList = this.extend())) || (isLess && (when = parserInput.$str("when"))) || (e = this.element())) {
if (when) {
condition = expect(this.conditions, 'expected condition');
} else if (condition) {
error("CSS guard can only be used at the end of selector");
} else if (extendList) {
if (allExtends) {
allExtends = allExtends.concat(extendList);
} else {
allExtends = extendList;
}
} else {
if (allExtends) { error("Extend can only be used at the end of selector"); }
c = parserInput.currentChar();
if (elements) {
elements.push(e);
} else {
elements = [ e ];
}
e = null;
}
if (c === '{' || c === '}' || c === ';' || c === ',' || c === ')') {
break;
}
}
if (elements) { return new(tree.Selector)(elements, allExtends, condition, index, fileInfo); }
if (allExtends) { error("Extend must be used to extend a selector, it cannot be used on its own"); }
},
attribute: function () {
if (! parserInput.$char('[')) { return; }
var entities = this.entities,
key, val, op;
if (!(key = entities.variableCurly())) {
key = expect(/^(?:[_A-Za-z0-9-\*]*\|)?(?:[_A-Za-z0-9-]|\\.)+/);
}
op = parserInput.$re(/^[|~*$^]?=/);
if (op) {
val = entities.quoted() || parserInput.$re(/^[0-9]+%/) || parserInput.$re(/^[\w-]+/) || entities.variableCurly();
}
expectChar(']');
return new(tree.Attribute)(key, op, val);
},
//
// The `block` rule is used by `ruleset` and `mixin.definition`.
// It's a wrapper around the `primary` rule, with added `{}`.
//
block: function () {
var content;
if (parserInput.$char('{') && (content = this.primary()) && parserInput.$char('}')) {
return content;
}
},
blockRuleset: function() {
var block = this.block();
if (block) {
block = new tree.Ruleset(null, block);
}
return block;
},
detachedRuleset: function() {
var blockRuleset = this.blockRuleset();
if (blockRuleset) {
return new tree.DetachedRuleset(blockRuleset);
}
},
//
// div, .class, body > p {...}
//
ruleset: function () {
var selectors, s, rules, debugInfo;
parserInput.save();
if (context.dumpLineNumbers) {
debugInfo = getDebugInfo(parserInput.i);
}
while (true) {
s = this.lessSelector();
if (!s) {
break;
}
if (selectors) {
selectors.push(s);
} else {
selectors = [ s ];
}
parserInput.commentStore.length = 0;
if (s.condition && selectors.length > 1) {
error("Guards are only currently allowed on a single selector.");
}
if (! parserInput.$char(',')) { break; }
if (s.condition) {
error("Guards are only currently allowed on a single selector.");
}
parserInput.commentStore.length = 0;
}
if (selectors && (rules = this.block())) {
parserInput.forget();
var ruleset = new(tree.Ruleset)(selectors, rules, context.strictImports);
if (context.dumpLineNumbers) {
ruleset.debugInfo = debugInfo;
}
return ruleset;
} else {
parserInput.restore();
}
},
rule: function (tryAnonymous) {
var name, value, startOfRule = parserInput.i, c = parserInput.currentChar(), important, merge, isVariable;
if (c === '.' || c === '#' || c === '&' || c === ':') { return; }
parserInput.save();
name = this.variable() || this.ruleProperty();
if (name) {
isVariable = typeof name === "string";
if (isVariable) {
value = this.detachedRuleset();
}
parserInput.commentStore.length = 0;
if (!value) {
// a name returned by this.ruleProperty() is always an array of the form:
// [string-1, ..., string-n, ""] or [string-1, ..., string-n, "+"]
// where each item is a tree.Keyword or tree.Variable
merge = !isVariable && name.length > 1 && name.pop().value;
// prefer to try to parse first if its a variable or we are compressing
// but always fallback on the other one
var tryValueFirst = !tryAnonymous && (context.compress || isVariable);
if (tryValueFirst) {
value = this.value();
}
if (!value) {
value = this.anonymousValue();
if (value) {
parserInput.forget();
// anonymous values absorb the end ';' which is required for them to work
return new (tree.Rule)(name, value, false, merge, startOfRule, fileInfo);
}
}
if (!tryValueFirst && !value) {
value = this.value();
}
important = this.important();
}
if (value && this.end()) {
parserInput.forget();
return new (tree.Rule)(name, value, important, merge, startOfRule, fileInfo);
} else {
parserInput.restore();
if (value && !tryAnonymous) {
return this.rule(true);
}
}
} else {
parserInput.forget();
}
},
anonymousValue: function () {
var match = parserInput.$re(/^([^@+\/'"*`(;{}-]*);/);
if (match) {
return new(tree.Anonymous)(match[1]);
}
},
//
// An @import directive
//
// @import "lib";
//
// Depending on our environment, importing is done differently:
// In the browser, it's an XHR request, in Node, it would be a
// file-system operation. The function used for importing is
// stored in `import`, which we pass to the Import constructor.
//
"import": function () {
var path, features, index = parserInput.i;
var dir = parserInput.$re(/^@import?\s+/);
if (dir) {
var options = (dir ? this.importOptions() : null) || {};
if ((path = this.entities.quoted() || this.entities.url())) {
features = this.mediaFeatures();
if (!parserInput.$char(';')) {
parserInput.i = index;
error("missing semi-colon or unrecognised media features on import");
}
features = features && new(tree.Value)(features);
return new(tree.Import)(path, features, options, index, fileInfo);
}
else {