query-util.cpp File Reference

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Description

Implementation of helpers for working with predicate queries.

Definition in file query-util.cpp.

#include "lib/error.hpp"
#include "lib/query-util.hpp"
#include "lib/util.hpp"
#include <boost/algorithm/string.hpp>
#include <functional>
#include <regex>
#include <map>

Typedefs
using	ChPredicate = std::function< bool(string::value_type)>

Functions
string	appendTerms (string const &pred1, string const &pred2)
uint	countPred (const string &)
	count the top-level predicates in the query string. More...
string	extractID (Symbol sym, const string &termString)
	(preliminary) helper: instead of really parsing and evaluating the terms, just do a regular expression match to extract the literal argument behind the given predicate symbol. More...
regex &	getTermRegex (Symbol sym)
bool	hasTerm (Symbol sym, string const &queryString)
void	normaliseID (string &id)
	ensure standard format for a given id string. More...
string	removeTerm (Symbol sym, string &queryString)
	(preliminary) helper: cut a term with the given symbol. More...

Variables
const regex	FIND_PREDICATE {string{"(\\w+)"} + MATCH_ARGUMENT}
ChPredicate	is_alpha = boost::algorithm::is_alpha()
ChPredicate	is_upper = boost::algorithm::is_upper()
Literal	MATCH_ARGUMENT = R"~(\(\s*([\w_\.\-]+)\s*\),?\s*)~"
map< Symbol, regex >	regexTable

Namespaces
	lib
	Implementation namespace for support and library code.

Function Documentation

normaliseID()

void normaliseID

(

string &

id

)

ensure standard format for a given id string.

Trim, sanitise and ensure the first letter is lower case.

Note

modifies the given string ref in place

Definition at line 61 of file query-util.cpp.

References lib::query::normaliseID().

Referenced by QueryUtils_test::check_normaliseID(), and lib::query::normaliseID().

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extractID()

string extractID	(	Symbol	sym,
		const string &	termString
	)

(preliminary) helper: instead of really parsing and evaluating the terms, just do a regular expression match to extract the literal argument behind the given predicate symbol.

e.g calling extractID ("stream", "id(abc), stream(mpeg)") yields "mpeg"

Definition at line 101 of file query-util.cpp.

References lib::query::extractID().

Referenced by QueryUtils_test::check_extractID(), and lib::query::extractID().

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removeTerm()

string removeTerm	(	Symbol	sym,
		string &	queryString
	)

(preliminary) helper: cut a term with the given symbol.

The term is matched, removed from the original string and returned

Note

parameter termString will be modified!

Todo:

as it seems we're not using the extracted term anymore, we could save the effort of rebuilding that term.

Definition at line 118 of file query-util.cpp.

References lib::query::removeTerm().

Referenced by QueryUtils_test::check_removeTerm(), and lib::query::removeTerm().

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countPred()

uint countPred

(

const string &

q

)

count the top-level predicates in the query string.

Note

this is a very hackish preliminary implementation. The regex used will flounder when applied to nested terms. We need a real parser for predicate logic terms (which we probably get for free when we embed a prolog system)...

usable for ordering queries, as more predicates usually mean more conditions, i.e. more constriction

Definition at line 146 of file query-util.cpp.

References lib::query::countPred().

Referenced by QueryUtils_test::check_countPred(), and lib::query::countPred().

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appendTerms()

string appendTerms	(	string const &	pred1,
		string const &	pred2
	)

Note

preliminary implementation without any syntax checks

Returns

a conjunction of the predicates

Definition at line 161 of file query-util.cpp.

References lib::query::appendTerms().

Referenced by lib::query::appendTerms().

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