From 7b2b9e3648920077fb53ced4f0b3bec3e0db5729 Mon Sep 17 00:00:00 2001 From: Valentin Gagarin Date: Thu, 22 Dec 2022 22:25:37 +0100 Subject: [PATCH] use more self-explanatory placeholder names --- doc/manual/src/language/operators.md | 121 +++++++++++---------------- 1 file changed, 50 insertions(+), 71 deletions(-) diff --git a/doc/manual/src/language/operators.md b/doc/manual/src/language/operators.md index 0c8cc6f57..459ea9945 100644 --- a/doc/manual/src/language/operators.md +++ b/doc/manual/src/language/operators.md @@ -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