Filter predicate improvements #115
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| basic-expr = exist-expr / paren-expr / (neg-op paren-expr) / relation-expr | ||
| exist-expr = [neg-op] path ; path existence or non-existence | ||
| path = rel-path / json-path | ||
| rel-path = "@" *(dot-selector / index-selector) |
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Are we only supporting a single selector here, or does the *( ... ) mean multiple?
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*() means zero or more repetitions of the contents of the brackets. See section 3.6 of RFC 5234.
| comparable = number / string-literal / ; primitive ... | ||
| true / false / null / ; values only | ||
| path ; path value |
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I'm curious, are we planning on supporting literal complex values (i.e. object / arrays) at some point later? Maybe this needs more discussion.
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I agree it needs more discussion, but let's defer such discussion for now to keep this PR nice and small.
draft-ietf-jsonpath-base.md
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| |:--:|:--:|:--:| | ||
| | 5 | Grouping | `(...)` | | ||
| | 4 | Logical NOT | `!` | | ||
| | 3 | Relations | `==`<br>`!=`<br>`<`<br>`>`<br>`<=`<br>`>=`<br>`=~`<br>` in ` | |
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Is it necessary to have each operator on its own line? Seems like we could do with two or three per line. Just a readability question.
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Not really. I've pushed a change which groups similar operators together on single lines.
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Perhaps I realise why this had one operator per line. Putting multiple on one line, separated by space or results in operators being wrapped in double quotes in the rendered text version (although not the HTML), thus:
+============+===========+===================+
| Precedence | Operator | Syntax |
| | type | |
+============+===========+===================+
| 5 | Grouping | (...) |
+------------+-----------+-------------------+
| 4 | Logical | ! |
| | NOT | |
+------------+-----------+-------------------+
| 3 | Relations | "==" "!=" |
| | | "<" "<=" ">" ">=" |
| | | "=~" |
| | | "in" |
+------------+-----------+-------------------+
| 2 | Logical | && |
| | AND | |
+------------+-----------+-------------------+
| 1 | Logical | || |
| | OR | |
+------------+-----------+-------------------+
This is pretty ugly, so I'm going to revert to one operator per line until someone can suggest better markup.
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Huh! The double quotes are there in the text version even when there is only one operator per line. Given I can't remove the ugliness, switching back to the multiple operators per line version.
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@cabo Do you know a way of avoiding these extraneous double quotes?
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The extra quotes are added by xml2rfc, but I don't know why or how to avoid this. I posted to the xml2rfc mailing list about this.
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So it seems the extra quotes are caused by a bug which will be fixed in the upcoming release of xml2rfc. I propose to leave them be for now and pick up the new release of xml2rfc in due course.
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* Generalise comparisons * Make regex operator conform to Perl etc. * Add operator precedence table Note: there are some extraneous double quotes in the text rendering of the operator precedence table. This is a known issue which should be fixed in the next release of xml2rfc: https://trac.ietf.org/trac/xml2rfc/ticket/600 Fixes #112 Fixes #113 Fixes #114
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* The behaviour of operators is consistent with the 'C'-family of programming languages.
<!-- need to clarify -->
I think having the precedence table now, above remark is obsolete.
… +The following table lists filter expression operators in order of precedence from highest to lowest.
+
+| Precedence | Operator type | Syntax |
+|:--:|:--:|:--:|
+| 5 | Grouping | `(...)` |
+| 4 | Logical NOT | `!` |
+| 3 | Relations | `==`<br>`!=`<br>`<`<br>`>`<br>`<=`<br>`>=`<br>`=~`<br>` in ` |
|
Fixes #112
Fixes #113
Fixes #114