Lionel Sambuc
6ed76e485e
* Adaptation of the grammar to make more regular w.r.t reference space
names placement.
* Implemented Type check
* Implemented prediction of the result set cardinality. This assumes:
+ A space is not infinite, this is required to compute complementary
sets as we can compute the whole space volume.
+ Density is mostly uniform, this allows us to assume the number of
results is related with a constant factor to the volume in space
of the selection.
+ The prediction is approximated by using the most pessimistic
resulting cardinality for each operator, in order to keep the
operation simple, and fast, at the expense of the precision.
* Implemented execution, which calls into a DB abstraction layer. That
layer is currently mostly empty. Execution is also implemented in a
naive way, and should most likely be optimised.
83 lines
1.8 KiB
ANTLR
83 lines
1.8 KiB
ANTLR
grammar queries;
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import filters;
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/**********************************************************************/
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/* FORMATTING DATA */
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/**********************************************************************/
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queries
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: projection_operators?
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;
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projection_operators
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: nifti_operator
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| json_operator
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;
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/* If selector is not provided, one (1) will be used as the values for
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* each position where there is a point in bag_expression.
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*
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* If it is provided, it MUST resolve to a NUMBER. */
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nifti_operator
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: 'nifti' '(' ( STRING ',' )? ( selector ',' )? bag_expression ')'
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;
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json_operator
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: 'json' '(' jslt ',' bag_expression ( ',' STRING )? ')'
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;
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jslt
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: json
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;
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/**********************************************************************/
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/* JSON */
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/**********************************************************************/
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/**
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* Taken and adapted from:
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* https://github.com/antlr/grammars-v4/blob/master/json/JSON.g4
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*
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* Some of the parser / lexer rules are in the imported grammar as well.
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*/
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json
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: json_value
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;
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json_obj
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: '{' json_pair (',' json_pair)* '}'
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| '{' '}'
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;
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json_pair
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: STRING ':' json_value
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;
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json_array
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: '[' json_value (',' json_value)* ']'
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| '[' ']'
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;
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json_value
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: STRING
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| json_number
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| json_obj
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| json_array
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| 'true'
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| 'false'
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| 'null'
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/* Add support to reference values from the selected bag. */
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| selector
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| aggregation_expr
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;
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/* The bag expression is implicit here, as this is te
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* second argument to the json operator */
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aggregation_expr
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: 'count' '(' 'distinct'? selector ')'
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| 'sum' '(' selector ')'
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| 'min' '(' selector ')'
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| 'max' '(' selector ')'
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| 'nifti' '(' selector ')'
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| 'mbb' '(' ')'
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;
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