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Last active Sep 14, 2019

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A *complete* listing of operators in Nix, and their predence.

Lower precedence means a stronger binding; ie. this list is sorted from strongest to weakest binding, and in the case of equal precedence between two operators, the associativity decides the binding.

Prec Abbreviation Example Assoc Description
1 SELECT e . attrpath [or def] none Select attribute denoted by the attribute path attrpath from set e. (An attribute path is a dot-separated list of attribute names.) If the attribute doesn’t exist, return default if provided, otherwise abort evaluation.
2 APP e1 e2 left Call function e1 with argument e2.
3 NEG -e none Numeric negation.
4 HAS_ATTR e ? attrpath none Test whether set e contains the attribute denoted by attrpath; return true or false.
5 CONCAT e1 ++ e2 right List concatenation.
6 MUL e1 * e2 left Numeric multiplication.
6 DIV e1 / e2 left Numeric division.
7 ADD e1 + e2 left Numeric addition, or string concatenation.
7 SUB e1 - e2 left Numeric subtraction.
8 NOT !e left Boolean negation.
9 UPDATE e1 // e2 right Return a set consisting of the attributes in e1 and e2 (with the latter taking precedence over the former in case of equally named attributes).
10 LT e1 < e2 left Less than.
10 LTE e1 <= e2 left Less than or equal.
10 GT e1 > e2 left Greater than.
10 GTE e1 >= e2 left Greater than or equal.
11 EQ e1 == e2 none Equality.
11 NEQ e1 != e2 none Inequality.
12 AND e1 && e2 left Logical AND.
13 OR e1 || e2 left Logical OR.
14 IMPL e1 -> e2 none Logical implication (equivalent to !e1 || e2).
@grahamc

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commented Aug 23, 2019

I didn't notice any missing operators, but I did port over the precedence info in to NixOS/nix#3056

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