This is an automated email from the ASF dual-hosted git repository.
henrib pushed a commit to branch JEXL-369
in repository https://gitbox.apache.org/repos/asf/commons-jexl.git
The following commit(s) were added to refs/heads/JEXL-369 by this push:
new c4b15d0e JEXL-369: documentation
c4b15d0e is described below
commit c4b15d0e62d699bf4f43c4983d2044070781d937
Author: henrib <hen...@apache.org>
AuthorDate: Mon May 9 10:30:17 2022 +0200
JEXL-369: documentation
---
src/site/xdoc/reference/syntax.xml | 57 ++++++++++++++++++++++++++++++++------
1 file changed, 49 insertions(+), 8 deletions(-)
diff --git a/src/site/xdoc/reference/syntax.xml
b/src/site/xdoc/reference/syntax.xml
index 63aec3ee..ea45e800 100644
--- a/src/site/xdoc/reference/syntax.xml
+++ b/src/site/xdoc/reference/syntax.xml
@@ -117,7 +117,8 @@
Scripts can be created with named parameters which
allow a later evaluation to be performed with arguments.
</p>
<p>
- By default scripts return the value of the last
evaluated statement.
+ By default, in the absence of an explicit
<code>return</code> statement, scripts return the value of the
+ last evaluated statement.
</p>
<p>
Using the <code>return</code> keyword, a script
will return the expression that follows (or null).
@@ -165,13 +166,26 @@
</tr>
<tr>
<td>Local variables</td>
- <td>Can be defined using the <code>var</code> keyword;
their identifying rules are the same as contextual variables.
+ <td>Can be defined using the <code>let</code>,
<code>const</code> and <code>var</code> keywords;
+ their identifying rules are the same as contextual
variables.
<ul>
- <li>Basic declaration: <code>var x;</code></li>
- <li>Declaration with assignment: <code>var
theAnswer = 42;</code></li>
+ <li><code>let</code> declares a local variable (or
a parameter) with a lexical block scope. The
+ variable can only be accessed within its
definition block and any nested sub-block. This also
+ forbids variable redeclaration within that scope.
Note: This emulates Java behavior which differs
+ from ECMAScript.</li>
+ <li><code>const</code> behaves as <code>let</code>
but will prevent the variable from being
+ reassigned by any side effect operator.</li>
+ <li>
+ <code>var</code> declares a variable whose scope
is the whole script and allows redefinition.
+ This behavior is altered by the
<code>JexlFeature#setLexical(true)</code> that will enforce a
+ lexical scope for all variables akin to
<code>let</code> declaration.
+ </li>
+ </ul>
+ <ul>
+ <li>Basic declaration: <code>let x;</code></li>
+ <li>Declaration with assignment: <code>const
theAnswer = 42;</code></li>
<li>Invalid declaration: <code>var x.y;</code></li>
</ul>
- Their scope is either the entire script scope or the
function definition block;
Local variables they take precedence in resolution
over contextual variables.
When scripts are created with named parameters, those
behave as local variables.
Local variables can not use <code>ant-style</code>
naming, only one identifier.
@@ -197,10 +211,16 @@
<td>
Defines a function within the script, usually
associated with a local variable assignment.
<code>var fun = function(x, y) { x + y }</code>
- The following syntax is also supported
- <code>var fun = (x, y) -> { x + y }</code>
+ The following syntaxes are also supported:
+ <ul>
+ <li><code>var fun = (x, y) -> { x + y }</code></li>
+ <li><code>var fun = (let x, let y) -> { x + y
}</code></li>
+ <li><code>const fun = (const x, const y) -> { x +
y }</code></li>
+ </ul>
If the function has only one argument the parentheses
may be omitted
- <code>var fun = x -> { x * x }</code>
+ <code>var fun = x -> { x * x }</code>.
+ Functions with an expression as body can forego the
curly brackets as in:
+ <code>var fun = x -> x * x </code>.
<p>Note that functions can use local variables and
parameters from their declaring script.
Those variables values are bound to the function
environment at definition time.</p>
<code>var t = 20; var s = function(x, y) {x + y + t};
t = 54; s(15, 7)</code>
@@ -605,6 +625,27 @@
<code>~33</code>, ~0010 0001 = 1101 1110 = -34.
</td>
</tr>
+ <tr>
+ <td>Left-shift <code><<</code></td>
+ <td>
+ The left shift operator (<<) shifts the first
operand the specified number of bits to the left.
+ <code>1 << 2</code> = 4
+ </td>
+ </tr>
+ <tr>
+ <td>Right-shift <code>>></code></td>
+ <td>
+ The right shift operator (>>) shifts the first operand
the specified number of bits to the right.
+ <code>4 >> 2</code> = 1
+ </td>
+ </tr>
+ <tr>
+ <td>Unsigned Right-shift <code>>>></code></td>
+ <td>
+ (zero-fill right shift) shifts the first operand the
specified number of bits to the right.
+ The sign bit becomes 0, so the result is always
non-negative.
+ </td>
+ </tr>
<tr>
<td>Ternary conditional <code>?:</code> </td>
<td>
