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93 lines
3.1 KiB
Plaintext
93 lines
3.1 KiB
Plaintext
---
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title: Operators
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introduction: >
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Sass supports a handful of useful `operators` for working with different
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values. These include the standard mathematical operators like `+` and `*`, as
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well as operators for various other types:
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---
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<%= partial 'documentation/snippets/operator-list', locals: {parens: false} %>
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<% heads_up do %>
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Early on in Sass's history, it added support for mathematical operations on
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[colors][]. These operations operated on each of the colors' RGB channels
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separately, so adding two colors would produce a color with the sum of their
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red channels as its red channel and so on.
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[colors]: values/colors
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This behavior wasn't very useful, since it channel-by-channel RGB arithmetic
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didn't correspond well to how humans perceive color. [Color functions][] were
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added which are much more useful, and color operations were deprecated.
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They're still supported in LibSass and Ruby Sass, but they'll produce warnings
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and users are strongly encouraged to avoid them.
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[Color functions]: modules/color
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<% end %>
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## Order of Operations
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Sass has a pretty standard [order of operations][], from tightest to loosest:
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[order of operations]: https://en.wikipedia.org/wiki/Order_of_operations#Programming_languages
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1. The unary operators [`not`][], [`+`, `-`][], and [`/`][].
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2. The [`*`, `/`, and `%` operators][].
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3. The [`+` and `-` operators][].
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4. The [`>`, `>=`, `<` and `<=` operators][].
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5. The [`==` and `!=` operators][].
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6. The [`and` operator][].
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7. The [`or` operator][].
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8. The [`=` operator][], when it's available.
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[`not`]: operators/boolean
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[`+`, `-`]: operators/numeric#unary-operators
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[`/`]: operators/string#unary-operators
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[`*`, `/`, and `%` operators]: operators/numeric
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[`+` and `-` operators]: operators/numeric
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[`>`, `>=`, `<` and `<=` operators]: operators/relational
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[`==` and `!=` operators]: operators/equality
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[`and` operator]: operators/boolean
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[`or` operator]: operators/boolean
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[`=` operator]: #single-equals
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<% example(autogen_css: false) do %>
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@debug 1 + 2 * 3 == 1 + (2 * 3); // true
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@debug true or false and false == true or (false and false); // true
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===
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@debug 1 + 2 * 3 == 1 + (2 * 3) // true
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@debug true or false and false == true or (false and false) // true
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<% end %>
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### Parentheses
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You can explicitly control the order of operations using parentheses. An
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operation inside parentheses is always evaluated before any operations outside
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of them. Parentheses can even be nested, in which case the innermost parentheses
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will be evaluated first.
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<% example(autogen_css: false) do %>
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@debug (1 + 2) * 3; // 6
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@debug ((1 + 2) * 3 + 4) * 5; // 65
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===
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@debug (1 + 2) * 3 // 6
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@debug ((1 + 2) * 3 + 4) * 5 // 65
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<% end %>
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## Single Equals
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Sass supports a special `=` operator that's only allowed in function arguments,
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which just creates an [unquoted string][] with its two operands separated by
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`=`. This exists for backwards-compatibility with very old IE-only syntax.
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[unquoted string]: values/strings#unquoted
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<% example do %>
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.transparent-blue {
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filter: chroma(color=#0000ff);
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}
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===
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.transparent-blue
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filter: chroma(color=#0000ff)
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<% end %>
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