问题
The Less compilers that I\'m using (OrangeBits and dotless 1.3.0.5) are aggressively translating
body { width: calc(100% - 250px - 1.5em); }
into
body { width: calc(-151.5%); }
Which is obviously not desired. I\'m wondering if there is a way to signal to the Less compiler to essentially ignore the attribute during compilation. I\'ve searched through the Less documentation and both compilers\' documentation, and I could not find anything.
Does Less or a Less compiler support this?
If not, is there a CSS extender that does?
回答1:
Less no longer evaluates expression inside calc by default since v3.00.
Original answer (Less v1.x...2.x):
Do this:
body { width: calc(~"100% - 250px - 1.5em"); }
In Less 1.4.0 we will have a strictMaths option which requires all Less calculations to be within brackets, so the calc will work "out-of-the-box". This is an option since it is a major breaking change. Early betas of 1.4.0 had this option on by default. The release version has it off by default.
回答2:
A very common usecase of calc is take 100% width and adding some margin around the element.
One can do so with:
@someMarginVariable = 15px;
margin: @someMarginVariable;
width: calc(~"100% - "@someMarginVariable*2);
width: -moz-calc(~"100% - "@someMarginVariable*2);
width: -webkit-calc(~"100% - "@someMarginVariable*2);
回答3:
There is several escaping options with same result:
body { width: ~"calc(100% - 250px - 1.5em)"; }
body { width: calc(~"100% - 250px - 1.5em"); }
body { width: calc(100% ~"-" 250px ~"-" 1.5em); }
回答4:
There's a tidier way to include variables inside the escaped calc, as explained in this post: CSS3 calc() function doesn't work with Less #974
@variable: 2em;
body{ width: calc(~"100% - @{variable} * 2");}
By using the curly brackets you don't need to close and reopen the escaping quotes.
来源：https://stackoverflow.com/questions/11972084/less-aggressive-compilation-with-css3-calc