BIND with more general binary operations #399
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Now allows the four basic arithmetic binary operations: + - * / TODO: Since the - is not recognized by a SYMBOL, the minus is currently realized via | (like a minus but vertical). I hope that Johannes finds a better way. I tried it out on a few example queries and it worked. TODO: If one of the two operands is a constant (from a previous BIND, like BIND(100 AS ?hundred), the operations don't work as expected and I am not sure why. Maybe Johannes can help.
joka921
approved these changes
May 11, 2021
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I gave you the hint how to make the - work as expected, you can change this if you want.
In general: I am currently working on
- a proper type system
- a proper SparqlParser
- proper expression evaluation.
This will also include this case, but until this is ready,
thank you very much for this valueable Improvement.
src/parser/SparqlParser.cpp
Outdated
| if (_lexer.current().raw != "+") { | ||
| binaryOperator = _lexer.current().raw; | ||
| // TODO: The minus `-` is not a SYMBOL, how do I accept it here as an | ||
| // alternative? Taking | for now as a silly workaround. |
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In SparqlLexer.cpp , line 60:
const std::string SparqlLexer::SYMBOL =
"([\\.\\{\\}\\(\\)\\=\\*,;:<>!\\|/\\^\\?\\*\\+])";
Here you can add the - (maybe as \\- vor safety) into the regex, then the ordinary syntax should work.
1. Symbol for minus is now - and not | (added to SYMBOL RE in lexer) 2. binaryOperator stored as char (and converted to string for cache key) 3. Fixed inconspicious bug from old code: &input(i, colIdx) should be &input(i, columns[colIdx])
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Now allows the four basic arithmetic binary operations: + - * /
TODO 1: Since the - is not recognized by a SYMBOL, the minus is currently
realized via | (like a minus but vertical). I hope that Johannes finds a
better way.
I tried it out on a few example queries and it worked.
TODO 2: If one of the two operands is a constant -- from a previous BIND,
like in BIND(100 AS ?hundred) BIND(100 * ?x AS ?y) -- the operations don't
work as expected and I am not sure why. Maybe Johannes can help.