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Merge pull request #223 from floriankramer/lang_tags
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Replaced `langMatches(a, b)` with `lang(a) = b`
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@niklas88
niklas88 committed Apr 17, 2019
2 parents bf13c05 + e04ce8e commit f2ba7ff
Showing 1 changed file with 107 additions and 54 deletions.
161 changes: 107 additions & 54 deletions src/parser/SparqlParser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -546,60 +546,6 @@ void SparqlParser::addFilter(const string& str, vector<SparqlFilter>* _filters,
// or not a literal.
rhs = parseLiteral(rhs, true);
}
if (pred == "langMatches") {
if (!pattern) {
AD_THROW(
ad_semsearch::Exception::BAD_QUERY,
"Invalid position for language filter. Probable cause: language "
"filters are currently not supported in HAVING clauses.");
}
if (!ad_utility::startsWith(lhs, "lang(")) {
AD_THROW(ad_semsearch::Exception::BAD_QUERY,
"langMatches filters"
"are only supported"
"when used with the "
"lang function.");
}
std::string lvar = lhs.substr(5, lhs.size() - 6);

auto langTag = rhs.substr(1, rhs.size() - 2);
// first find a predicate for the given variable
auto it =
std::find_if(pattern->_whereClauseTriples.begin(),
pattern->_whereClauseTriples.end(),
[&lvar](const auto& tr) { return tr._o == lvar; });
while (it != pattern->_whereClauseTriples.end() &&
ad_utility::startsWith(it->_p, "?")) {
it = std::find_if(it + 1, pattern->_whereClauseTriples.end(),
[&lvar](const auto& tr) { return tr._o == lvar; });
}
if (it == pattern->_whereClauseTriples.end()) {
LOG(INFO)
<< "language filter variable " + rhs +
"that did not appear as object in any suitable triple. "
"using special literal-to-language triple instead.\n";
auto langEntity = ad_utility::convertLangtagToEntityUri(langTag);
SparqlTriple triple(lvar, LANGUAGE_PREDICATE, langEntity);
// Quadratic in number of triples in query.
// Shouldn't be a problem here, though.
// Could use a (hash)-set instead of vector.
if (std::find(pattern->_whereClauseTriples.begin(),
pattern->_whereClauseTriples.end(),
triple) != pattern->_whereClauseTriples.end()) {
LOG(INFO) << "Ignoring duplicate triple: " << str << std::endl;
} else {
pattern->_whereClauseTriples.push_back(triple);
}
} else {
// replace the triple
string taggedPredicate = '@' + langTag + '@' + it->_p;
*it = SparqlTriple(it->_s, taggedPredicate, it->_o);
}

// Convert the language filter to a special triple
// to make it more efficient (no need for string resolution)
return;
}
if (pred == "regex") {
SparqlFilter f;
f._type = SparqlFilter::REGEX;
Expand Down Expand Up @@ -660,6 +606,62 @@ void SparqlParser::addFilter(const string& str, vector<SparqlFilter>* _filters,
_filters->emplace_back(f2);
return;
}
if (pred == "langMatches") {
if (!pattern) {
AD_THROW(
ad_semsearch::Exception::BAD_QUERY,
"Invalid position for language filter. Probable cause: language "
"filters are currently not supported in HAVING clauses.");
}
if (!ad_utility::startsWith(lhs, "lang(")) {
AD_THROW(ad_semsearch::Exception::BAD_QUERY,
"langMatches filters"
"are only supported"
"when used with the "
"lang function.");
}
std::string lvar = lhs.substr(5, lhs.size() - 6);

auto langTag = rhs.substr(1, rhs.size() - 2);
// first find a predicate for the given variable
auto it =
std::find_if(pattern->_whereClauseTriples.begin(),
pattern->_whereClauseTriples.end(),
[&lvar](const auto& tr) { return tr._o == lvar; });
while (it != pattern->_whereClauseTriples.end() &&
ad_utility::startsWith(it->_p, "?")) {
it = std::find_if(it + 1, pattern->_whereClauseTriples.end(),
[&lvar](const auto& tr) { return tr._o == lvar; });
}
if (it == pattern->_whereClauseTriples.end()) {
LOG(INFO)
<< "language filter variable " + rhs +
"that did not appear as object in any suitable triple. "
"using special literal-to-language triple instead.\n";
auto langEntity = ad_utility::convertLangtagToEntityUri(langTag);
SparqlTriple triple(lvar, LANGUAGE_PREDICATE, langEntity);
// Quadratic in number of triples in query.
// Shouldn't be a problem here, though.
// Could use a (hash)-set instead of vector.
if (std::find(pattern->_whereClauseTriples.begin(),
pattern->_whereClauseTriples.end(),
triple) != pattern->_whereClauseTriples.end()) {
LOG(INFO) << "Ignoring duplicate triple: " << str << std::endl;
} else {
pattern->_whereClauseTriples.push_back(triple);
}
} else {
// replace the triple
string taggedPredicate = '@' + langTag + '@' + it->_p;
*it = SparqlTriple(it->_s, taggedPredicate, it->_o);
}

// Convert the language filter to a special triple
// to make it more efficient (no need for string resolution)
return;
}
AD_THROW(ad_semsearch::Exception::BAD_QUERY,
"Unknown keyword at beginning of filter: " + str);
}
}

Expand Down Expand Up @@ -688,10 +690,61 @@ void SparqlParser::addFilter(const string& str, vector<SparqlFilter>* _filters,
AD_THROW(ad_semsearch::Exception::BAD_QUERY,
"Unknown syntax for filter: " + filter);
}

// Check if we filter on the language of the left side of the
// filter.
if (ad_utility::startsWith(tokens[0], "lang") && tokens[1] == "=") {
if (!pattern) {
AD_THROW(ad_semsearch::Exception::BAD_QUERY,
"Invalid position for language filter. Probable cause: language "
"filters are currently not supported in HAVING clauses.");
}
std::string lhs = tokens[0];
std::string rhs = tokens[2];
std::string lvar = lhs.substr(5, lhs.size() - 6);

auto langTag = rhs.substr(1, rhs.size() - 2);
// first find a predicate for the given variable
auto it = std::find_if(pattern->_whereClauseTriples.begin(),
pattern->_whereClauseTriples.end(),
[&lvar](const auto& tr) { return tr._o == lvar; });
while (it != pattern->_whereClauseTriples.end() &&
ad_utility::startsWith(it->_p, "?")) {
it = std::find_if(it + 1, pattern->_whereClauseTriples.end(),
[&lvar](const auto& tr) { return tr._o == lvar; });
}
if (it == pattern->_whereClauseTriples.end()) {
LOG(INFO) << "language filter variable " + rhs +
"that did not appear as object in any suitable triple. "
"using special literal-to-language triple instead.\n";
auto langEntity = ad_utility::convertLangtagToEntityUri(langTag);
SparqlTriple triple(lvar, LANGUAGE_PREDICATE, langEntity);
// Quadratic in number of triples in query.
// Shouldn't be a problem here, though.
// Could use a (hash)-set instead of vector.
if (std::find(pattern->_whereClauseTriples.begin(),
pattern->_whereClauseTriples.end(),
triple) != pattern->_whereClauseTriples.end()) {
LOG(INFO) << "Ignoring duplicate triple: " << str << std::endl;
} else {
pattern->_whereClauseTriples.push_back(triple);
}
} else {
// replace the triple
string taggedPredicate = '@' + langTag + '@' + it->_p;
*it = SparqlTriple(it->_s, taggedPredicate, it->_o);
}

// Convert the language filter to a special triple
// to make it more efficient (no need for string resolution)
return;
}

if (tokens[0].size() == 0 || tokens[0][0] != '?' || tokens[2].size() == 0) {
AD_THROW(ad_semsearch::Exception::NOT_YET_IMPLEMENTED,
"Filter not supported yet: " + filter);
}

SparqlFilter f;
f._lhs = tokens[0];
f._rhs = tokens[2];
Expand Down

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