set-analysis-parser
BNF Parser for Set Analysis expressions in QlikView and Qlik Sense.
(Table of contents generated by [verb])
This is work in progress, read below.
About this project
Why?
The backbone of the new Set Analysis Wizard will be a parser which is able to parse and therefore "decode" existing Set Analysis statements into a structure which can be used in programmatic way. This is not only beneficial for the Set Analysis Wizard but instead this parser could be used in many other projects.
Semantic Sugar Layer
On top of that it is the goal to return a descriptive explanation of a Set Analysis statement.
For example:
The goal is that you can paste in the following expression
Sum({$<Customer=P({1<Product={'Shoe'}>}Customer)>}Sales)
and you'll get back the following description
Returns the Sum of Sales for the current selection, but only for those customers that have bought the product "Shoe".
The Parser
I have chosen to use Jison to parse existing Set Analysis statements.
If you have a look into the online documentation of Qlik Sense, you'll find the BNF syntax for sets there:
// Added entry point
definition ::= aggr_type ( set_expression field_expression )
// From the online help
// http://help.qlik.com/sense/2.0/en-US/online/Subsystems/Hub/Content/ChartFunctions/SetAnalysis/syntax-for-sets.htm
set_expression ::= { set_entity { set_operator set_entity } }
set_entity ::= set_identifier [ set_modifier ]
set_identifier ::= 1 | $ | $N | $_N | bookmark_id | bookmark_name
set_operator ::= + | - | * | /
set_modifier ::= < field_selection {, field_selection } >
field_selection ::= field_name [ = | += | ¬–= | *= | /= ] element_set_expression
element_set_expression ::= element_set { set_operator element_set }
element_set ::= [ field_name ] | { element_list } | element_function
element_list ::= element { , element }
element_function ::= ( P | E ) ( [ set_expression ] [ field_name ] )
element ::= field_value | " search_mask "
Test
First install dependencies:
npm install
Then run the Mocha tests:
npm test
Contributing
Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.
At the current state of the project ("very early beginning") I am seeking for some help:
- I need as many Set Analysis statements to prove parser
- Commit them to
test/expressions.txtor create an issue
- Commit them to
- Help to write the parser
- Finally I'd like to create a web-page where you paste in an existing Set Analysis statement and you would just get the semantic description returned.
Related projects
Some related projects (Qlik Sense Visualization Extensions) I have recently created:
set-analysis-wizard: The well known Set Analysis Wizard for QlikView and Qlik Sense. | homepage
Author
Stefan Walther
License
Copyright © 2015 Stefan Walther Released under the GNU General Public License license.
This file was generated by verb-cli on October 29, 2015.