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| -rw-r--r-- | doc/manual/src/language/operators.md | 236 |
1 files changed, 210 insertions, 26 deletions
diff --git a/doc/manual/src/language/operators.md b/doc/manual/src/language/operators.md index e06e73b2d..aeb77b72a 100644 --- a/doc/manual/src/language/operators.md +++ b/doc/manual/src/language/operators.md @@ -1,28 +1,212 @@ # Operators -The table below lists the operators in the Nix language, in -order of precedence (from strongest to weakest binding). - -| Name | Syntax | Description | Associativity | Precedence | -| ------------------------ | ----------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------- | ---------- | -| Select | *e* `.` *attrpath* \[ `or` *def* \] | 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 *def* if provided, otherwise abort evaluation. | none | 1 | -| Application | *e1* *e2* | Call function *e1* with argument *e2*. | left | 2 | -| Arithmetic Negation | `-` *e* | Arithmetic negation. | none | 3 | -| Has Attribute | *e* `?` *attrpath* | Test whether set *e* contains the attribute denoted by *attrpath*; return `true` or `false`. | none | 4 | -| List Concatenation | *e1* `++` *e2* | List concatenation. | right | 5 | -| Multiplication | *e1* `*` *e2*, | Arithmetic multiplication. | left | 6 | -| Division | *e1* `/` *e2* | Arithmetic division. | left | 6 | -| Addition | *e1* `+` *e2* | Arithmetic addition. | left | 7 | -| Subtraction | *e1* `-` *e2* | Arithmetic subtraction. | left | 7 | -| String Concatenation | *string1* `+` *string2* | String concatenation. | left | 7 | -| Not | `!` *e* | Boolean negation. | none | 8 | -| Update | *e1* `//` *e2* | 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). | right | 9 | -| Less Than | *e1* `<` *e2*, | Arithmetic/lexicographic comparison. | none | 10 | -| Less Than or Equal To | *e1* `<=` *e2* | Arithmetic/lexicographic comparison. | none | 10 | -| Greater Than | *e1* `>` *e2* | Arithmetic/lexicographic comparison. | none | 10 | -| Greater Than or Equal To | *e1* `>=` *e2* | Arithmetic/lexicographic comparison. | none | 10 | -| Equality | *e1* `==` *e2* | Equality. | none | 11 | -| Inequality | *e1* `!=` *e2* | Inequality. | none | 11 | -| Logical AND | *e1* `&&` *e2* | Logical AND. | left | 12 | -| Logical OR | *e1* <code>||</code> *e2* | Logical OR. | left | 13 | -| Logical Implication | *e1* `->` *e2* | Logical implication (equivalent to <code>!e1 || e2</code>). | none | 14 | +## Select + +> *e* `.` *attrpath* \[ `or` *def* \] + +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 *def* if provided, otherwise abort evaluation. + +Associativity: none + +Precedence: 1 + +## Application + +> *e1* *e2* + +Call function *e1* with argument *e2*. + +Associativity: left + +Precedence: 2 + +## Arithmetic Negation + +> `-` *e* + +Arithmetic negation. + +Associativity: none + +Precedence: 3 + +## Has Attribute + +> *e* `?` *attrpath* + +Test whether set *e* contains the attribute denoted by *attrpath*; return `true` or `false`. + +Associativity: none + +Precedence: 4 + +## List Concatenation + +> *e1* `++` *e2* + +List concatenation. + +Associativity: right + +Precedence: 5 + +## Multiplication + +> *e1* `*` *e2*, + +Arithmetic multiplication. + +Associativity: left + +Precedence: 6 + +## Division + +> *e1* `/` *e2* + +Arithmetic division. + +Associativity: left + +Precedence: 6 + +## Addition + +> *e1* `+` *e2* + +Arithmetic addition. + +Associativity: left + +Precedence: 7 + +## Subtraction + +> *e1* `-` *e2* + +Arithmetic subtraction. + +Associativity: left + +Precedence: 7 + +## String Concatenation + +> *string1* `+` *string2* + +String concatenation. + +Associativity: left + +Precedence: 7 + +## Not + +> `!` *e* + +Boolean negation. + +Associativity: none + +Precedence: 8 + +## Update + +> *e1* `//` *e2* + +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). + +Associativity: right + +Precedence: 9 + +## Less Than + +> *e1* `<` *e2*, + +Arithmetic/lexicographic comparison. + +Associativity: none + +Precedence: 10 + +## Less Than or Equal To + +> *e1* `<=` *e2* + +Arithmetic/lexicographic comparison. + +Associativity: none + +Precedence: 10 + +## Greater Than + +> *e1* `>` *e2* + +Arithmetic/lexicographic comparison. + +Associativity: none + +Precedence: 10 + +## Greater Than or Equal To + +> *e1* `>=` *e2* + +Arithmetic/lexicographic comparison. + +Associativity: none + +Precedence: 10 + +## Equality + +> *e1* `==` *e2* + +Equality. + +Associativity: none + +Precedence: 11 + +## Inequality + +> *e1* `!=` *e2* + +Inequality. + +Associativity: none + +Precedence: 11 + +## Logical AND + +> *e1* `&&` *e2* + +Logical AND. + +Associativity: left + +Precedence: 12 + +## Logical OR + +> *e1* <code>||</code> *e2* + +Logical OR. + +Associativity: left + +Precedence: 13 + +## Logical Implication + +> *e1* `->` *e2* + +Logical implication (equivalent to <code>!e1 || e2</code>). + +Associativity: none + +Precedence: 14 + |