Higher-Order Functions - Revision history

CG: Text replacement - "syntaxhighlight" to "pre"

2023-12-01T16:39:25Z

Text replacement - "syntaxhighlight" to "pre"

CG: Text replacement - "" to "

2023-12-01T16:31:15Z

Text replacement - "<syntaxhighlight lang="xquery">" to "<pre lang='xquery'>"

2023-12-01T16:30:00Z

Text replacement - "</syntaxhighlight>" to "</pre>"

2023-08-27T20:10:48Z

2023-03-09T15:28:22Z

2023-03-09T13:18:43Z

2023-03-09T13:06:16Z

Text replacement - "'''Signatures'''" to "'''Signature'''"

2023-03-09T12:59:06Z

Function Types

2020-02-27T12:17:37Z

2017-12-12T12:44:19Z

@@ Line 257: / Line 257: @@
 Calculating the ''product'' of a sequence of integers for example is easy in <code>Java</code>:
-<syntaxhighlight lang="java">
+<pre lang="java">
 public int product(int[] seq) {
    int result = 1;

@@ Line 224: / Line 224: @@
      fn:for-each-pair(
        $seq,
-       fn:tail($seq),
+       tail($seq),
        function($a, $b) { $a le $b }
+     )
@@ Line 329: / Line 329: @@
    if(empty($input)) then $zero
    else local:fold-left(
-     fn:tail($input),
+     tail($input),
-     $action($zero, fn:head($input)),
+     $action($zero, head($input)),
      $action
+   )
@@ Line 393: / Line 393: @@
    if(empty($input)) then $zero
    else $action(
-     fn:head($input),
+     head($input),
      local:fold-right(tail($input), $zero, $action)
+   )

@@ Line 323: / Line 323: @@
 <syntaxhighlight lang="xquery">
 declare function local:fold-left(
-   $seq as item()*,
+   $input   as item()*,
-   $seed as item()*,
+   $zero    as item()*,
-   $function as function(item()*, item()) as item()*
+   $action  as function(item()*, item()) as item()*
 ) as item()* {
-   if(empty($seq)) then $seed
+   if(empty($input)) then $zero
    else local:fold-left(
-     fn:tail($seq),
+     fn:tail($input),
-     $function($seed, fn:head($seq)),
+     $action($zero, fn:head($input)),
-     $function
+     $action
+   )
 };
@@ Line 387: / Line 387: @@
 |<syntaxhighlight lang="xquery">
 declare function local:fold-right(
-   $seq as item()*,
+   $input   as item()*,
-   $seed as item()*,
+   $zero    as item()*,
-   $function as function(item(), item()*) as item()*
+   $action  as function(item(), item()*) as item()*
 ) as item()* {
-   if(empty($seq)) then $seed
+   if(empty($input)) then $zero
-   else $function(
+   else $action(
-     fn:head($seq),
+     fn:head($input),
-     local:fold-right(tail($seq), $seed, $function)
+     local:fold-right(tail($input), $zero, $action)
+   )
 };

@@ Line 59: / Line 59: @@
 {|
 |-
-| width='120' | '''Signatures'''
+| width='120' | '''Signature'''
 |{{Func|fn:for-each|$seq as item()*, $function as function(item()) as item()*)|item()*}}
 |-
@@ Line 108: / Line 108: @@
 {|
 |-
-| width='120' | '''Signatures'''
+| width='120' | '''Signature'''
 |{{Func|fn:filter|$seq as item()*, $pred as function(item()) as xs:boolean)|item()*}}
 |-
@@ Line 170: / Line 170: @@
 {|
 |-
-| width='120' | '''Signatures'''
+| width='120' | '''Signature'''
 |{{Func|fn:for-each-pair|$seq1 as item()*, $seq2 as item()*, $function as function(item(), item()) as item()*|item()*}}
 |-
@@ Line 265: / Line 265: @@
 {|
 |-
-| width='120' | '''Signatures'''
+| width='120' | '''Signature'''
 |{{Func|fn:fold-left|$seq as item()*, $seed as item()*, $function as function(item()*, item()) as item()*|item()*}}
 |-
@@ Line 327: / Line 327: @@
 {|
 |-
-| width='120' | '''Signatures'''
+| width='120' | '''Signature'''
 |{{Func|fn:fold-right|$seq as item()*, $seed as item()*, $function as function(item(), item()*) as item()*|item()*}}
 |-

@@ Line 22: / Line 22: @@
 <syntaxhighlight lang="xquery">
 declare function local:char-at(
-   $str as xs:string,
+   $str  as xs:string,
-   $pos as xs:integer
+   $pos  as xs:integer
 ) as xs:string {
    fn:substring($str, $pos, 1)