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use more self-explanatory placeholder names

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Valentin Gagarin 2022-12-22 22:25:37 +01:00
parent 969e5ad5bf
commit 7b2b9e3648
1 changed files with 50 additions and 71 deletions
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doc/manual/src/language/operators.md
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@ -2,11 +2,11 @@
## Attribute selection
> *e* `.` *attrpath* \[ `or` *def* \]
> *attrset* `.` *attrpath* \[ `or` *value* \]
Select the attribute denoted by attribute path *attrpath* from attribute set *e*.
Select the attribute denoted by attribute path *attrpath* from attribute set *attrset*.
An attribute path is a dot-separated list of attribute names.
If the attribute doesn’t exist, return *def* if provided, otherwise abort evaluation.
If the attribute doesn’t exist, return *value* if provided, otherwise abort evaluation.
Associativity: none
@ -14,9 +14,9 @@ Precedence: 1
## Function application
> *f* *e*
> *f* *a*
Call function *f* with argument *e*.
Call function *f* with argument *a*.
Associativity: left
@ -24,7 +24,9 @@ Precedence: 2
## Arithmetic negation
> `-` *e*
> `-` *n*
Flip the sign of the number *n*.
Associativity: none
@ -32,9 +34,9 @@ Precedence: 3
## Has attribute
> *e* `?` *attrpath*
> *attrset* `?` *attrpath*
Test whether set *e* contains the attribute denoted by *attrpath*; return `true` or `false`.
Test whether attribute set *attrset* contains the attribute denoted by *attrpath*; return `true` or `false`.
Associativity: none
@ -42,9 +44,9 @@ Precedence: 4
## List concatenation
> *e1* `++` *e2*
> *list1* `++` *list2*
Concatenate lists *e1* and *e2*.
Concatenate lists *list1* and *list2*.
Associativity: right
@ -52,9 +54,9 @@ Precedence: 5
## Multiplication
> *e1* `*` *e2*,
> *n1* `*` *n2*,
Multiply numbers *e1* and *e2*.
Multiply numbers *n1* and *n2*.
Associativity: left
@ -62,9 +64,9 @@ Precedence: 6
## Division
> *e1* `/` *e2*
> *n1* `/` *n2*
Divide numbers *e1* and *e2*.
Divide numbers *n1* and *n2*.
Associativity: left
@ -72,9 +74,9 @@ Precedence: 6
## Subtraction
> *e1* `-` *e2*
> *n1* `-` *n2*
Subtract numbers *e2* from *e1*.
Subtract numbers *n2* from *n1*.
Associativity: left
@ -82,9 +84,9 @@ Precedence: 7
## Addition
> *e1* `+` *e2*
> *n1* `+` *n2*
Add numbers *e1* and *e2*.
Add numbers *n1* and *n2*.
Associativity: left
@ -140,82 +142,59 @@ Precedence: 7
## Logical negation (`NOT`)
> `!` *e*
> `!` *b*
Negate the Boolean value *e*.
Negate the Boolean value *b*.
Associativity: none
Precedence: 8
## Merge attribute sets
## Update
> *e1* `//` *e2*
> *attrset1* `//` *attrset1*
Return a set consisting of all the attributes in *e1* and *e2*.
Update attribute set *attrset1* with names and values from *attrset2*.
The returned attribute set will have 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
## 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
> *e1* `<` *e2*,
- 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 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 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 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
## Equality
> *e1* `==` *e2*
Check *e1* and *e2* for equality.
Check expressions *e1* and *e2* for value equality.
- Attribute sets and lists are compared recursively, and therefore are fully evaluated.
- Comparison of functions always returns `false`.
@ -238,9 +217,9 @@ Precedence: 11
## Logical conjunction (`AND`)
> *e1* `&&` *e2*
> *b1* `&&` *b2*
Return `true` if and only if both `e1` and `e2` evaluate to `true`, otherwise `false`.
Return `true` if and only if both `b1` and `b2` evaluate to `true`, otherwise `false`.
Associativity: left
@ -248,9 +227,9 @@ Precedence: 12
## Logical disjunction (`OR`)
> *e1* `||` *e2*
> *b1* `||` *b2*
Return `true` if at least `e1` or `e2` evaluate to `true`, otherwise `false`.
Return `true` if at least one of `b1` or `b2` evaluate to `true`, otherwise `false`.
Associativity: left
@ -258,11 +237,11 @@ Precedence: 13
## Logical implication
> *e1* `->` *e2*
> *b1* `->` *b2*
Return `false` if *e1* evaluates to `true` and *e2* evaluates to `false`, otherwise `true`.
Return `false` if *b1* evaluates to `true` and *b2* evaluates to `false`, otherwise `true`.
Equivalent to `!`*e1* `||` *e2*.
Equivalent to `!`*b1* `||` *b2*.
Associativity: none