That's one of the advantages to mini-language - you don't need to
compile it. It would be nice to have a tool that converts schemas to
Java model classes however.
-Adrian
On 3/7/2012 11:35 PM, Mansour Al Akeel wrote:
Not sure if this discussion open for users as well.
I don't use mini-lang, and prefer to do things in java. But I am
wondering why not move all the repetitive code to java (copying
fields). Those who prefer to use mini-lang can have an XSLT that will
produce the java code as they want. This way, every contributor can
customize their XSLT and have their grammar that will produce the java
code. Maintenance will not be possible with mini-lang, since the code
generated is committed to SVN is in java.
On Wed, Mar 7, 2012 at 1:18 PM, Adrian Crum
<adrian.c...@sandglass-software.com> wrote:
I created a Wiki page to help get things started:
https://cwiki.apache.org/confluence/display/OFBADMIN/Mini-language+Reference
I put just enough information in it to work on the layout. I will continue
working on it when I have time. Everyone with write access is welcome to
work on it also. The information is based on the mini-language Java code -
which is the ultimate authority. The schemas are inaccurate - they should be
used only for looking up schema-supplied default values.
The goal is to document the current mini-language grammar, and add proposed
changes. If a proposal is approved, then it can get a green check mark. If a
proposal is vetoed, then it can get a red X. When everyone agrees on the
grammar, the document will be updated, and it will move out of the draft
stage. Then the job will be to work on the Java and XML code to make it
match the grammar.
I put a couple of proposals in the page to help get things started.
Let me know what you think.
-Adrian
On 3/6/2012 9:42 AM, Adrian Crum wrote:
<set field="field4" from="parameters.inputField1 + 10"/> <!-- use Minilang
built-in and efficient support: not currently supported but maybe something
to consider in the future -->
The from attribute contains a UEL expression, so it is currently
supported.
-Adrian
On 3/6/2012 9:33 AM, Jacopo Cappellato wrote:
On Mar 6, 2012, at 10:03 AM, Adrian Crum wrote:
Replacing FSE with Groovy is a bad idea. Adam and I optimized FSE so
that it is very lightweight and fast. I also optimized the UEL integration
so there is very little overhead in the evaluation process. Switching
everything to Groovy will slow things down and increase memory usage. Also
keep in mind that Groovy creates a class for every script, so we will run
out of permgen space again.
Ok, makes perfect sense, thank you.
I think a wiser strategy would be to make mini-lang as feature complete
as possible, and include a from-script attribute for any feature gaps. In
other words, use from-script as a last resort - because it is costly.
+1: by the way we could still use the "from" attribute for both:
<set field="field4" from="parameters.inputField1"/> <!-- use Minilang
built-in and efficient support -->
<set field="field4" from="parameters.inputField1 + 10"/> <!-- use
Minilang built-in and efficient support: not currently supported but maybe
something to consider in the future -->
<set field="field4" from="groovy: parameters.inputField1 + 10"/> <!-- use
Groovy (inefficient) -->
Jacopo
-Adrian
On 3/6/2012 8:53 AM, Jacopo Cappellato wrote:
On Mar 6, 2012, at 9:32 AM, Adrian Crum wrote:
I don't understand what you mean by supporting a limited number of
types. Currently, mini-lang supports any type - thanks to the conversion
framework.
The conversion framework is fine; I was thinking that we could
implicitly (by default) treat in Minilang all the numbers as BigDecimals,
all the strings as GStrings/Expandable Strings; where special conversions
are required than the type can be specified.
I like the idea of changing the from-field attribute to from. I would
like to see a from-script attribute added:
<set field="field4" from-script="groovy: parameters.inputField1 +
10"/><!-- Use Groovy -->
and why not:
<set field="field4" from="parameters.inputField1"/><!-- Use Groovy
internally: refactor OFBiz custom code to delegate on Groovy the evaluation
of simple assignments; this could potentially replace FlexibleStringExpander
related code -->
<set field="field4" from="groovy: parameters.inputField1 + 10"/><!--
Use Groovy explicitly to evaluate the expression (use the same "from"
attribute instead of a separate "from-script")-->
<set field="field4" from="parameters.inputField1 + 10"/><!-- Use Groovy
(by default, configurable) to evaluate the expression-->
<set field="field4" from="beanshell: parameters.inputField1 + 10"/><!--
Use Beanshell to evaluate the expression-->
?
Then we can remove script support from expressions, which will
eliminate ugly hacks like:
<set field="field4" value="${groovy: parameters.inputField1 + 10}"/>
+1
Jacopo
-Adrian
On 3/6/2012 7:31 AM, Jacopo Cappellato wrote:
I am a big fan of Minilang too.
The "evolution" strategy that I would like to see implemented for
Minilang is actually the same one I would liketo see applied to OFBiz
framework in general: review the current usage of the tool, fix existing
usage for consistency (upgrade old code to use newer mechanisms offered by
the tool), get rid of unused or old mechanisms in the attempt to slim down
the size of the framework code, unify/simplify mechanisms based on lesson
learned; all of this could be useful even to prepare the future migration to
a different tool (e.g. Groovy).
I know that it is very vague and doesn't add much to this thread but
I like the approach suggested by Adrian.
In my opinion, a good way to define a new version of the "set"
operation could be that of analyzing how we are currently using the
operation in OFBiz: as a starting point we could start by searching all
occurrences of "<set " string in OFBiz, then review them and see different
patterns; discuss and define the few ones that we like more, convert all
code to use them consistently, then (or in the same phase) define the new
element to better implement the patterns that we like.
And now I am switching to the "brainstorming" mode :-)
Kind regards,
Jacopo
========================
<brainstorming>
I would like to have a "set" operation that implements some of the
ideas of the "configure by exception" concept.
As regards the type supported, but pending the review of existing
usage, we may consider to only support these:
* Object
* List
* Map
* BigDecimal/BigInteger (all numbers in Minilang should be treated as
BigDecimal; no support for Integer, Float etc...)
* String (expander i.e. the equivalent of GString in Groovy)
* a date object
Then we could get rid of the "from-field" attribute and replace it
with a "from" attribute that can take as input a single field (as it is now)
or an expression; some examples (all the following are evaluated using
Groovy except where a different language is specified i.e. default scripting
language):
<set field="field1" from="parameters.inputField1"/> // field1 will
have the same type of inputField1
<set field="field2" from="parameters.inputField1 +
parameters.inputField2"/> // if inputField1 and inputField2 are numbers
then field2 will be the BigDecimal sum of the two
<set field="field3" from="parameters.inputField1 * 10"/>
<set field="field4" from="script:bsh parameters.inputField1 + 10"/>
// use Beanshell
<set field="field5" from="parameters.inputField1" type="BigDecimal"/>
// if inputField1 is a string representation of a number we can convert
with the explicit definition of the type
For the constant values (I am not sure if it is a good idea, but for
now I will throw it out):
<set field="stringField" value="This is a string"/>
<set field="stringField" value="This is a string with a
${variable}"/>
// the following two are equivalent
<set field="bigDecimalField" value="100"/> // the system attempt
to parse "100" as a number first (BigDecimal) and then as a string
<set field="bigDecimalField" value="100" type="BigDecimal"/>
<set field="stringField" value="100" type="String"/> // treat the
field as a string
</brainstorming>
On Mar 5, 2012, at 9:07 PM, Adrian Crum wrote:
I am not one of those people. I use mini-lang almost exclusively.
-Adrian
On 3/5/2012 7:46 PM, Anil Patel wrote:
Adrian,
Thanks for starting this thread.
While we all love mini-lang, I am wondering if we should really ask
ourselves if we really want to overhaul mini-lang or should we consider
alternates. From what I know, Not many people like to build application
using mini lang. Many end up using Java or Groovy.
Thanks and Regards
Anil Patel
HotWax Media Inc
On Mar 5, 2012, at 9:47 AM, Adrian Crum wrote:
Mini-language has evolved a lot over the years. Most of the
development has occurred on an as-needed basis, so there is no clear design
or implementation - things just get tacked on over time.
A recent discussion has opened up the possibility to rework the
mini-language<set> element. From my perspective, that task is long
overdue.
Also, the schemas are out of date, and they are unnecessarily
complicated. So, those need a thorough going over.
While we are at it, why don't we create a draft design document
based on the current implementation, and then use it to look for other ways
mini-language can be improved? We can all offer suggestions and comments,
agree on a final design, finalize the draft, and then implement it in code.
The design document then becomes the developer's reference.
What do you think?
-Adrian
