I have 2 LESS CSS files called core.less and style.less
core.less is located under: \css\core.less and its contents are below:
body {
background: #bg_color;
color: #font_color;
}
style.less is located under: \css\green\style.less and its contents are below:
#bg_color: #0F0;
#font_color: #FFF;
#import "../../core.less";
The core.less file contains all the css rules, in LESS format, but does not provide the definitions for the variables.
The style.less defines all the variables referenced in core.less, and then imports the core.less file.
I have no problems compiling style.less as it imports all the rules from the core file. The core.less file cannot be compiled - it will generate errors since it does not contain the variable definitions.
I would now like to compile the core.css file as well (just to make sure there are no errors in my LESS rules). Is there any way of adding some kind of dummy/placeholder variables in the core.less file such that it can also be complied without generating errors and still work with the setup I have explained above?
I am open to suggestions on changing the format / structure of the files.
By importing core.less into style.less you are compiling the "LESS rules" of core.less.
Perhaps you should not define variables, needed in core.less, outside of core.less. I typically make "core" files (in any programming language, really) have no dependencies on the rest of the code.
Related
The site I'm working on uses the rails asset pipeline and an application.scss file to import and process different CSS files.
However, some stylesheets are used in specific places, and for those, it makes little sense to import them into the global manifest. But not so importing them requires importing variables.scss, and possibly mixins.scss into the sheet itself (so they'll process correctly), resulting in duplicate code in the final CSS.
Is there a way to basically tell the preprocessor - "trust me, the variable/mixin you're seeing will be defined by the time everything gets processed"?
Otherwise, I don't see how to avoid importing every sheet into a single manifest, which seems bloated.
Thanks.
The short answer to your question is no. The variables need to be defined in a logical order from when they are called in compilation. It's like a "chicken and the egg" scenario.
From what I can ascertain in your description, the project you're working on is not compiling into a unified workflow, but chunking out into modular portions relational to your file structure. IF this is the case, what you can do at the beginning of each file is reference the variables file from the root.
In a normal workflow, you would import your scss files based on your defined hierarchy like so:
sass/style.scss
/* Main Stylesheet */
#import "variables";
#import "mixins";
/* Modular Sections */
#import "layout/header";
#import "layout/body";
#import "layout/footer";
would compile out to one stylesheet style.css with a command sass sass/style.scss:style.css
What I'm assuming your project does is have all the /* Modular Sections */ files compile out into their own CSS files.
layout/header.scss
/* Header Stylesheet */
#import "../variables";
#import "../mixins";
Given a files structure that resembles:
/root
style.scss
variables.scss
mixins.scss
/layouts
header.scss
body.scss
footer.scss
This all seems kinda silly though. I don't know all the parameters that go into your current sass compilation, but I'd recommend using a unified workflow.
You can use Partials so the compiler will not try to interpret variables etc.
Basically, rename the files that you do not want the compiler to interpret -- but will be available when compiled -- with an underscore before the filename.
eg.
_filename.scss
If I understood well you want to avoid copies of the same css in css files caused by using #import in scss. I solved this problems by doing a hierarchical three.
For exemple consider the home.scss file, where you import header.scss and footer.scss.
Both header.scss and footer.scss use specific colors that you import from a file named colors.scss:
// colors.scss
$MidnightBlue: #00478f;
$RedOrange: #ff5d00;
$MistyBlue: #d8e1e7;
$Ebony: #2a231f;
Now you could import colors in header.scss, footer.scss and maybe even in home.scss. The result is that in home.css the code of colors.scss is repeated 3 times.
A solution is importing colors.scss only in header.scss. Then in home.scss the first #import that you specify is #import "header.scss"; and then #import "footer.scss";, thus you can use the colors variables in footer.scss and in home.scss even if you don't import them directly in footer.scss and home.scss. That's because the variables of colors are imported before the footer and compiled before the rest of the code in home.scss.
Now if you check home.css you shouldn't see repeated code
When at first you write the color variables in footer you will receive an error because they are not defined, but it disappear when you import footer in home.scss
If you #import the same SASS file (e.g. variables.sass) in multiple files and then #import those files in the one main.sass file, the resulting main.css file will contain the content of variables multiple times.
A good way of structuring SASS files is to obey the rule of importing each file only once. Iconic architecture is the 7-1 Pattern. You basically decompose your SASS files into atomic parts and then import those in appropriate order only once in the main file.
I'm confused about how LESS files work. Can I just create a bunch of them and they're just magically included? How do I know they're being included in the right cascading order? What is the significance of the .import.less suffix? I have these files:
client/stylesheets/variables.import.less
#headline-font: 'Khula', Helvetica, Arial, sans-serif;
client/stylesheets/main.less
h1 {
font-family: #headline-font;
}
And Meteor does not like this:
While building the application:
client/stylesheets/main.less:14:16: Less compiler error: variable
#headline-font is undefined
The default Less compiler for Meteor compiles every file with the .less extension into a single CSS file. Partial files with variables and mixins should not be compile into a single file, but imported into your project only.
The .import.less suffix prevents your files from being compiled into a CSS files, but can imported into your other Less files still.
See also: Overide bootstrap base class attributes in less and meteor
In your situation you will possible need the following line of code in your main.less file:
#import "client/stylesheets/variables.import.less"
You need to include variables.import.less in main.less.
You may find this answer useful: https://stackoverflow.com/a/23527787/3624916
I've a project with less and CSS files mixed (vendor stuff). I want to optimize all files either CSS or less to one merged CSS file. Usually I've one less file which imports all needed files. But it doesn't work with imported CSS files. It just export the "import "foo.css"" to the merged CSS file.
How can I do that?
Use #import (inline) directive.
You can read more about it here.
I suggest to treat .css files imported like they would be .less with the following syntax:
#import (less) "foo.css";
This results in a final compiled .css file that include rows from original .css imported one, followed by processed LESS rows.
Currently using Bootstrap, compiling with Codekit, and also have a separate style.less that I'm working on.
In variables.less:
#blue: #0096EF;
In style.less, I have the following:
.title-text {color: #blue;}
#import: "variables.less";
In bootstrap.less:
#import: "style.less";
#import: "variables.less";
Am I doing this right? To my mind, when bootstrap is compiled it results in variables.less occurring twice.
you should be able to go with import of variables.less once in bootstrap as first import instance, and do not include it second time in actual style.less. Because you are right on your assumption, it will import variable.less again. meaning you are importing same variables in two locations.
P.S. as long as variables.less that defines variables that you will be using is imported before you access variables themselves you will be fine.
#color-black: #000;
.color {
color: #color-black;
}
I discovered this is also a Codekit issue too, as I am using Codekit to compile the less files.
Solution:
Create style.less and edit it as intended, reference #blue variable
(not declared in current document)
On save, Codekit returns a compile error, due to un-declared variable in style.less. Ignore the error.
In bootstrap.less #import style.less
Save bootstrap.less, it compiles without issue
Call bootstrap.css in the html doc
Incidentally, I encountered a Codekit bug between step 2 and 3. After step 2, Codekit no longer watches or compiles anything. To solve, I needed to remove the watched project and then re-add it to Codekit.
I started using LESS today. But it's kinda weird. This code does not work. I get an error:
! Variable Name Error: #linkColor in a is undefined.
My bootstrap:
#import "variables.less";
#import "normalize.less";
variables.less:
#linkColor: #08c;
#linkColorHover: darken(#linkColor, 15%);
normalize.less:
a {
color: #linkColor;
}
a:visited {
color: #linkColor;
}
a:hover {
color: #linkColorHover;
}
When I make an
#import "variables.less"
in the normalize.less file, everything works fine.
Thanks for your help :)
This other question ultimately led me to the right answer.
It looks like the LESS compiler is silently failing if files are encoded with a BOM. (That's a Byte Order Mark for those not familiar with the term.) This is the default setting in some editors, such as Visual Studio.
The compiler barfs up an error on the BOM if it's in your root file, but seems to fail silently for #import-ed files.
Try saving your files as UTF-8 without a BOM, and see if that solves your problem.
This error can also occur via bad imports in the files you're importing.
I also encountered this issue, when using multiple layers of import, and the 'lessc' compiler from Node.js:
The original file imported a file (which we will call 'child')
The child file imported a file (which we will call 'grandchild')
The grandchild was imported
I attempted to compile the original file, and received the same 'undefined variable' behavior. I could see the variable was defined in the child and the syntax lookedcorrect.
No prior errors were displayed.
The problem turned out that the child was not importing the grandchild properly. Ie,
#import grandchild.less
rather than:
#import "grandchild.less";
Fixing the child importing the grandchild made the original see the variables defined in the child.
This seems like a bug in less - ie, the bad import should show up in the 'lessc' output, so one day it will probably be fixed. Until then, I hope this helps.
There may be another possible root cause.
Here is my original Gruntfile.js:
less: {
compile: {
files: {
'css/less.css': 'less/**/*.less'
}
}
},
The wildcard makes LESS compiler compile all .less files under that folder and merge all results into one CSS. And I got errors running grunt less:compile:
NameError: .transition is undefined in less/core/html.less on line 38, column 3
Once I changed 'less/**/*.less' into 'less/css.less', the compilation succeeds.
I encountered the same problem using Winless compiler.
Some of the .less files i was importing into master.less were empty. when i removed these from the list of imported files my variables were recognized!
To help any others that may come across this not want duplicate CSS generated from multiple imports, you have two options.
Either #import-once the variables / mixins files you need in each file you need to use them in.
Use #import-once "filename.less"; to prevent duplicates.
Upgrade to LESS > 1.4.0, when it arrives; From the less website:
"The statement #import acts differently before and after 1.4.0. It acts as #import-multiple in all older versions and as #import-once in all less.js versions after 1.4.0."
You can also get this error if you are trying to import the file twice (not a good idea) and the first import is before your variables referenced in your.less file have been loaded
Note: I'm using django compress
in index.html i had:
{% compress css %}
<link href="{{ STATIC_URL }}less/timepicker.less" rel="stylesheet" type="text/less">
<link href="{{ STATIC_URL }}less/style.less" rel="stylesheet" type="text/less">
{% endcompress %}
then in styles.less i had
...
#import "timepick.less";
I think it is because of which master less file you are compiling. Likewise
If you have Less/Project_name/project.less and in this project.less you import the variable less and all the other files which has in the directory.
You just have to compile project.less into your css, not all less files. If you try to compile project.less and variables.less at a time you will have this error. And you can avoid redundant declaration of importing the variable less files
I would use the nested rules in the normalize.less :
a {
color: #linkColor;
&:visited {color: #linkColor;}
&:hover {color: #linkColorHover;}
}
And in the #import, you don't need to use the ".less", it's optional :
#import "variables";
#import "normalize";
I don't know if this can help...
One other weirdly specific situation in which this occurs: if you're using .NET and dotless, the compiler will choke on nested media queries with variable specifiers. If you have code like this:
#media (min-width: #aVariable) {
.some-class{
margin: 10px;
#media (min-width: #anotherVariable) {
margin: 20px;
}
}
... then dotless will tell you that it can't find the definition for #anotherVariable, even if it's used three lines above.
For me its happened when using #Import-once and nothing help.
but with #Import its worked.
as i read in the last version of the Less the Import will work as Import-once.