Nix (language): Difference between revisions
imported>Makefu good enough i guess |
imported>Makefu add operators |
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# <code>{ x, y ? "foo", z ? "bar", ... }: z + y + x</code> a set pattern, which can also set defaults. ellipse means that the function may receive extra arguments. | # <code>{ x, y ? "foo", z ? "bar", ... }: z + y + x</code> a set pattern, which can also set defaults. ellipse means that the function may receive extra arguments. | ||
# <code>args@{ x, y, z, ... }: z + y + x + args.a</code> an <code>@</code> pattern which can be used to match extra arguments and store them in the <code>args</code> set. | # <code>args@{ x, y, z, ... }: z + y + x + args.a</code> an <code>@</code> pattern which can be used to match extra arguments and store them in the <code>args</code> set. | ||
=== Operators === | |||
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. | |||
{| class="wikitable" | |||
!width="6%"| Prec | |||
!width="13%"| Abbreviation | |||
!width="24%"| Example | |||
!width="13%"| Assoc | |||
!width="42%"| Description | |||
|- | |||
| 1 | |||
| SELECT | |||
| <code>e . attrpath [or def]</code> | |||
| none | |||
| Select attribute denoted by the attribute path <code>attrpath</code> from set <code>e</code>. (An attribute path is a dot-separated list of attribute names.) If the attribute doesn’t exist, return <code>default</code> if provided, otherwise abort evaluation. | |||
|- | |||
| 2 | |||
| APP | |||
| <code>e1 e2</code> | |||
| left | |||
| Call function <code>e1</code> with argument <code>e2</code>. | |||
|- | |||
| 3 | |||
| NEG | |||
| <code>-e</code> | |||
| none | |||
| Numeric negation. | |||
|- | |||
| 4 | |||
| HAS_ATTR | |||
| <code>e ? attrpath</code> | |||
| none | |||
| Test whether set <code>e</code> contains the attribute denoted by <code>attrpath</code>; return true or false. | |||
|- | |||
| 5 | |||
| CONCAT | |||
| <code>e1 ++ e2</code> | |||
| right | |||
| List concatenation. | |||
|- | |||
| 6 | |||
| MUL | |||
| <code>e1 * e2</code> | |||
| left | |||
| Numeric multiplication. | |||
|- | |||
| 6 | |||
| DIV | |||
| <code>e1 / e2</code> | |||
| left | |||
| Numeric division. | |||
|- | |||
| 7 | |||
| ADD | |||
| <code>e1 + e2</code> | |||
| left | |||
| Numeric addition, or string concatenation. | |||
|- | |||
| 7 | |||
| SUB | |||
| <code>e1 - e2</code> | |||
| left | |||
| Numeric subtraction. | |||
|- | |||
| 8 | |||
| NOT | |||
| <code>!e</code> | |||
| left | |||
| Boolean negation. | |||
|- | |||
| 9 | |||
| UPDATE | |||
| <code>e1 // e2</code> | |||
| right | |||
| Return a set consisting of the attributes in <code>e1</code> and <code>e2</code> (with the latter taking precedence over the former in case of equally named attributes). | |||
|- | |||
| 10 | |||
| LT | |||
| <code>e1 < e2</code> | |||
| left | |||
| Less than. | |||
|- | |||
| 10 | |||
| LTE | |||
| <code>e1 <= e2</code> | |||
| left | |||
| Less than or equal. | |||
|- | |||
| 10 | |||
| GT | |||
| <code>e1 > e2</code> | |||
| left | |||
| Greater than. | |||
|- | |||
| 10 | |||
| GTE | |||
| <code>e1 >= e2</code> | |||
| left | |||
| Greater than or equal. | |||
|- | |||
| 11 | |||
| EQ | |||
| <code>e1 == e2</code> | |||
| none | |||
| Equality. | |||
|- | |||
| 11 | |||
| NEQ | |||
| <code>e1 != e2</code> | |||
| none | |||
| Inequality. | |||
|- | |||
| 12 | |||
| AND | |||
| <code>e1 && e2</code> | |||
| left | |||
| Logical AND. | |||
|- | |||
| 13 | |||
| OR | |||
| <code><nowiki>e1 || e2</nowiki></code> | |||
| left | |||
| Logical OR. | |||
|- | |||
| 14 | |||
| IMPL | |||
| <code>e1 -> e2</code> | |||
| none | |||
| Logical implication (equivalent to <code><nowiki>!e1 || e2</nowiki></code>). | |||
|} | |||
Source: [https://gist.github.com/joepie91/c3c047f3406aea9ec65eebce2ffd449d Gist of joepie91] | |||
=== imports === | === imports === | ||