diff options
| -rw-r--r-- | doc/manual/src/language/operators.md | 99 | ||||
| -rw-r--r-- | doc/manual/src/language/values.md | 2 |
2 files changed, 61 insertions, 40 deletions
diff --git a/doc/manual/src/language/operators.md b/doc/manual/src/language/operators.md index aeb77b72a..e3a00d32b 100644 --- a/doc/manual/src/language/operators.md +++ b/doc/manual/src/language/operators.md @@ -1,36 +1,36 @@ # Operators -## Select +## Attribute selection > *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. +Select the attribute denoted by attribute path *attrpath* from attribute 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 +## Function application -> *e1* *e2* +> *f* *e* -Call function *e1* with argument *e2*. +Call function *f* with argument *e*. Associativity: left Precedence: 2 -## Arithmetic Negation +## Arithmetic negation > `-` *e* -Arithmetic negation. - Associativity: none Precedence: 3 -## Has Attribute +## Has attribute > *e* `?` *attrpath* @@ -40,11 +40,11 @@ Associativity: none Precedence: 4 -## List Concatenation +## List concatenation > *e1* `++` *e2* -List concatenation. +Concatenate lists *e1* and *e2*. Associativity: right @@ -54,7 +54,7 @@ Precedence: 5 > *e1* `*` *e2*, -Arithmetic multiplication. +Multiply numbers *e1* and *e2*. Associativity: left @@ -64,7 +64,7 @@ Precedence: 6 > *e1* `/` *e2* -Arithmetic division. +Divide numbers *e1* and *e2*. Associativity: left @@ -74,7 +74,7 @@ Precedence: 6 > *e1* `+` *e2* -Arithmetic addition. +Add numbers *e1* and *e2*. Associativity: left @@ -84,77 +84,90 @@ Precedence: 7 > *e1* `-` *e2* -Arithmetic subtraction. +Subtract numbers *e2* from *e1*. Associativity: left Precedence: 7 -## String Concatenation +## String concatenation > *string1* `+` *string2* -String concatenation. +Concatenate *string1* and *string1* and merge their string contexts. Associativity: left Precedence: 7 -## Not +## Logical negation (`NOT`) > `!` *e* -Boolean negation. +Negate the Boolean value *e*. Associativity: none Precedence: 8 -## Update +## Merge attribute sets > *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). +Return a set consisting of all the attributes in *e1* and *e2*. +If an attribute name is present in both, the attribute value from the former is taken. Associativity: right Precedence: 9 -## Less Than +## Less than > *e1* `<` *e2*, -Arithmetic/lexicographic comparison. +- Arithmetic comparison for numbers +- Lexicographic comparison for strings and paths +- Lexicographic comparison for lists: + Elements at the same index in both lists are compared according to their type and skipped if they are equal. Associativity: none Precedence: 10 -## Less Than or Equal To +## Less than or equal to > *e1* `<=` *e2* -Arithmetic/lexicographic comparison. +- Arithmetic comparison for numbers +- Lexicographic comparison for strings and paths +- Lexicographic comparison for lists: + Elements at the same index in both lists are compared according to their type and skipped if they are equal. Associativity: none Precedence: 10 -## Greater Than +## Greater than > *e1* `>` *e2* -Arithmetic/lexicographic comparison. +- Arithmetic comparison for numbers +- Lexicographic comparison for strings and paths +- Lexicographic comparison for lists: + Elements at the same index in both lists are compared according to their type and skipped if they are equal. Associativity: none Precedence: 10 -## Greater Than or Equal To +## Greater than or equal to > *e1* `>=` *e2* -Arithmetic/lexicographic comparison. +- Arithmetic comparison for numbers +- Lexicographic comparison for strings and paths +- Lexicographic comparison for lists: + Elements at the same index in both lists are compared according to their type and skipped if they are equal. Associativity: none @@ -164,7 +177,12 @@ Precedence: 10 > *e1* `==` *e2* -Equality. +Check *e1* and *e2* for equality. + +- Attribute sets and lists are compared recursively, and therefore are fully evaluated. +- Comparison of functions always returns `false`. +- Integers are coerced to floating point numbers if compared to floating point numbers. +- Floating point numbers only differ up to a limited precision. Associativity: none @@ -174,39 +192,40 @@ Precedence: 11 > *e1* `!=` *e2* -Inequality. +Equivalent to `! (`*e1* `==` *e2* `)` Associativity: none Precedence: 11 -## Logical AND +## Logical conjunction (`AND`) > *e1* `&&` *e2* -Logical AND. +Return `true` if and only if both `e1` and `e2` evaluate to `true`, otherwise `false`. Associativity: left Precedence: 12 -## Logical OR +## Logical disjunction (`OR`) -> *e1* <code>||</code> *e2* +> *e1* `||` *e2* -Logical OR. +Return `true` if at least `e1` or `e2` evaluate to `true`, otherwise `false`. Associativity: left Precedence: 13 -## Logical Implication +## Logical implication -> *e1* `->` *e2* +> *e1* `->` *e2* -Logical implication (equivalent to <code>!e1 || e2</code>). +Return `false` if *e1* evaluates to `true` and *e2* evaluates to `false`, otherwise `true`. + +Equivalent to `!`*e1* `||` *e2*. Associativity: none Precedence: 14 - diff --git a/doc/manual/src/language/values.md b/doc/manual/src/language/values.md index 08baa8f95..d92f287a3 100644 --- a/doc/manual/src/language/values.md +++ b/doc/manual/src/language/values.md @@ -89,6 +89,8 @@ return integers, whereas any operation involving at least one floating point number will have a floating point number as a result. + Floating point numbers only differ up to a limited precision. + - <a id="type-path" href="#type-path">Path</a> *Paths*, e.g., `/bin/sh` or `./builder.sh`. A path must contain at |