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Posted to issues@commons.apache.org by "Henri Biestro (JIRA)" <ji...@apache.org> on 2016/06/20 12:52:05 UTC
[jira] [Comment Edited] (JEXL-200) Support for dynamic scripting in
jexl scripts
[ https://issues.apache.org/jira/browse/JEXL-200?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15339437#comment-15339437 ]
Henri Biestro edited comment on JEXL-200 at 6/20/16 12:51 PM:
--------------------------------------------------------------
Setting aside the dedicated syntax - for which I'm dont see the necessity -, we can already achieve what's described:
{code}
public static class Eval {
private JexlEngine jexl;
public JexlScript fn(String src) {
return jexl.createScript(src);
}
void setJexl(JexlEngine je) {
jexl = je;
}
}
@Test
public void test200() throws Exception {
JexlContext jc = new MapContext();
Map<String, Object> funcs = new HashMap<String, Object>();
Eval eval = new Eval();
funcs.put(null, eval);
JexlEngine jexl = new JexlBuilder().namespaces(funcs).create();
eval.setJexl(jexl);
String src = "var f = fn(\'(x)->{x + 42}\'); f(y)";
JexlScript s200 = jexl.createScript(src, "y");
Assert.assertEquals(142, s200.execute(jc, 100));
Assert.assertEquals(52, s200.execute(jc, 10));
}
{code}
was (Author: henrib):
Setting aside the dedicated syntax - for which I'm dont see the necessity -, we can already achieve what's described:
{code}
public static class Eval {
private JexlEngine jexl;
public JexlScript fn(String src) {
return jexl.createScript(src);
}
void setJexl(JexlEngine je) {
jexl = je;
}
}
@Test
public void test200() throws Exception {
JexlContext jc = new MapContext();
Map<String, Object> funcs = new HashMap<String, Object>();
Eval eval = new Eval();
funcs.put(null, eval);
JexlEngine jexl = new JexlBuilder().namespaces(funcs).create();
eval.setJexl(jexl);
String src = "var f = fn(\'(x)->{x + 42}\'); f(y)";
JexlScript s200 = jexl.createScript(src, "y");
Assert.assertEquals(142, s200.execute(jc, 100));
Assert.assertEquals(52, s200.execute(jc, 10));
}
{code}
> Support for dynamic scripting in jexl scripts
> ---------------------------------------------
>
> Key: JEXL-200
> URL: https://issues.apache.org/jira/browse/JEXL-200
> Project: Commons JEXL
> Issue Type: New Feature
> Affects Versions: 3.0
> Reporter: Dmitri Blinov
> Priority: Minor
>
> Allow for dynamically defined functions inside a script where the definition of the function comes from a string expression, for example:
> {code}
> var x = function(y) => "return y+2";
> {code}
> the defined function should be accessible after its definition is successfully parsed as ordinary function, and can be evaluated in the current context.
> {code}
> if (x(40) eq 42) {...
> {code}
> I think the idea of dynamic script evaluation is not unusual, and though to some extent can be implemented via side-added functions like *eval(expr)* a dedicated syntax for this will benefit from the simplicity of ordinal functions and the ability to control mapping of the arguments between a caller and the defined function.
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