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Diffstat (limited to 'third_party/nix/doc/manual/expressions/language-operators.xml')
| -rw-r--r-- | third_party/nix/doc/manual/expressions/language-operators.xml | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/third_party/nix/doc/manual/expressions/language-operators.xml b/third_party/nix/doc/manual/expressions/language-operators.xml new file mode 100644 index 000000000000..4f11bf52938f --- /dev/null +++ b/third_party/nix/doc/manual/expressions/language-operators.xml @@ -0,0 +1,222 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-language-operators"> + +<title>Operators</title> + +<para><xref linkend='table-operators' /> lists the operators in the +Nix expression language, in order of precedence (from strongest to +weakest binding).</para> + +<table xml:id='table-operators'> + <title>Operators</title> + <tgroup cols='3'> + <thead> + <row> + <entry>Name</entry> + <entry>Syntax</entry> + <entry>Associativity</entry> + <entry>Description</entry> + <entry>Precedence</entry> + </row> + </thead> + <tbody> + <row> + <entry>Select</entry> + <entry><replaceable>e</replaceable> <literal>.</literal> + <replaceable>attrpath</replaceable> + [ <literal>or</literal> <replaceable>def</replaceable> ] + </entry> + <entry>none</entry> + <entry>Select attribute denoted by the attribute path + <replaceable>attrpath</replaceable> from set + <replaceable>e</replaceable>. (An attribute path is a + dot-separated list of attribute names.) If the attribute + doesn’t exist, return <replaceable>def</replaceable> if + provided, otherwise abort evaluation.</entry> + <entry>1</entry> + </row> + <row> + <entry>Application</entry> + <entry><replaceable>e1</replaceable> <replaceable>e2</replaceable></entry> + <entry>left</entry> + <entry>Call function <replaceable>e1</replaceable> with + argument <replaceable>e2</replaceable>.</entry> + <entry>2</entry> + </row> + <row> + <entry>Arithmetic Negation</entry> + <entry><literal>-</literal> <replaceable>e</replaceable></entry> + <entry>none</entry> + <entry>Arithmetic negation.</entry> + <entry>3</entry> + </row> + <row> + <entry>Has Attribute</entry> + <entry><replaceable>e</replaceable> <literal>?</literal> + <replaceable>attrpath</replaceable></entry> + <entry>none</entry> + <entry>Test whether set <replaceable>e</replaceable> contains + the attribute denoted by <replaceable>attrpath</replaceable>; + return <literal>true</literal> or + <literal>false</literal>.</entry> + <entry>4</entry> + </row> + <row> + <entry>List Concatenation</entry> + <entry><replaceable>e1</replaceable> <literal>++</literal> <replaceable>e2</replaceable></entry> + <entry>right</entry> + <entry>List concatenation.</entry> + <entry>5</entry> + </row> + <row> + <entry>Multiplication</entry> + <entry> + <replaceable>e1</replaceable> <literal>*</literal> <replaceable>e2</replaceable>, + </entry> + <entry>left</entry> + <entry>Arithmetic multiplication.</entry> + <entry>6</entry> + </row> + <row> + <entry>Division</entry> + <entry> + <replaceable>e1</replaceable> <literal>/</literal> <replaceable>e2</replaceable> + </entry> + <entry>left</entry> + <entry>Arithmetic division.</entry> + <entry>6</entry> + </row> + <row> + <entry>Addition</entry> + <entry> + <replaceable>e1</replaceable> <literal>+</literal> <replaceable>e2</replaceable> + </entry> + <entry>left</entry> + <entry>Arithmetic addition.</entry> + <entry>7</entry> + </row> + <row> + <entry>Subtraction</entry> + <entry> + <replaceable>e1</replaceable> <literal>-</literal> <replaceable>e2</replaceable> + </entry> + <entry>left</entry> + <entry>Arithmetic subtraction.</entry> + <entry>7</entry> + </row> + <row> + <entry>String Concatenation</entry> + <entry> + <replaceable>string1</replaceable> <literal>+</literal> <replaceable>string2</replaceable> + </entry> + <entry>left</entry> + <entry>String concatenation.</entry> + <entry>7</entry> + </row> + <row> + <entry>Not</entry> + <entry><literal>!</literal> <replaceable>e</replaceable></entry> + <entry>none</entry> + <entry>Boolean negation.</entry> + <entry>8</entry> + </row> + <row> + <entry>Update</entry> + <entry><replaceable>e1</replaceable> <literal>//</literal> + <replaceable>e2</replaceable></entry> + <entry>right</entry> + <entry>Return a set consisting of the attributes in + <replaceable>e1</replaceable> and + <replaceable>e2</replaceable> (with the latter taking + precedence over the former in case of equally named + attributes).</entry> + <entry>9</entry> + </row> + <row> + <entry>Less Than</entry> + <entry> + <replaceable>e1</replaceable> <literal><</literal> <replaceable>e2</replaceable>, + </entry> + <entry>none</entry> + <entry>Arithmetic comparison.</entry> + <entry>10</entry> + </row> + <row> + <entry>Less Than or Equal To</entry> + <entry> + <replaceable>e1</replaceable> <literal><=</literal> <replaceable>e2</replaceable> + </entry> + <entry>none</entry> + <entry>Arithmetic comparison.</entry> + <entry>10</entry> + </row> + <row> + <entry>Greater Than</entry> + <entry> + <replaceable>e1</replaceable> <literal>></literal> <replaceable>e2</replaceable> + </entry> + <entry>none</entry> + <entry>Arithmetic comparison.</entry> + <entry>10</entry> + </row> + <row> + <entry>Greater Than or Equal To</entry> + <entry> + <replaceable>e1</replaceable> <literal>>=</literal> <replaceable>e2</replaceable> + </entry> + <entry>none</entry> + <entry>Arithmetic comparison.</entry> + <entry>10</entry> + </row> + <row> + <entry>Equality</entry> + <entry> + <replaceable>e1</replaceable> <literal>==</literal> <replaceable>e2</replaceable> + </entry> + <entry>none</entry> + <entry>Equality.</entry> + <entry>11</entry> + </row> + <row> + <entry>Inequality</entry> + <entry> + <replaceable>e1</replaceable> <literal>!=</literal> <replaceable>e2</replaceable> + </entry> + <entry>none</entry> + <entry>Inequality.</entry> + <entry>11</entry> + </row> + <row> + <entry>Logical AND</entry> + <entry><replaceable>e1</replaceable> <literal>&&</literal> + <replaceable>e2</replaceable></entry> + <entry>left</entry> + <entry>Logical AND.</entry> + <entry>12</entry> + </row> + <row> + <entry>Logical OR</entry> + <entry><replaceable>e1</replaceable> <literal>||</literal> + <replaceable>e2</replaceable></entry> + <entry>left</entry> + <entry>Logical OR.</entry> + <entry>13</entry> + </row> + <row> + <entry>Logical Implication</entry> + <entry><replaceable>e1</replaceable> <literal>-></literal> + <replaceable>e2</replaceable></entry> + <entry>none</entry> + <entry>Logical implication (equivalent to + <literal>!<replaceable>e1</replaceable> || + <replaceable>e2</replaceable></literal>).</entry> + <entry>14</entry> + </row> + </tbody> + </tgroup> +</table> + +</section> |