# HG changeset patch
# User František Kučera <franta-hg@frantovo.cz>
# Date 1549366914 -3600
# Node ID 82bd0f57a88993ab250028d2c9b5891cf37b7ebb
# Parent  c9fece435aa2c36a0039d5c916b94c3d7ef9ed97
add --drop option: all Guile code will be executed but not relational output for given relation will be generated

diff -r c9fece435aa2 -r 82bd0f57a889 src/CLIParser.h
--- a/src/CLIParser.h	Tue Feb 05 12:14:58 2019 +0100
+++ b/src/CLIParser.h	Tue Feb 05 12:41:54 2019 +0100
@@ -46,12 +46,6 @@
 		}
 	}
 
-	bool parseBoolean(const string_t& value, const string_t& optionName) {
-		if (value == L"true") return true;
-		else if (value == L"false") return false;
-		else throw relpipe::cli::RelpipeCLIException(L"Unable to parse boolean value of option: " + optionName + L" (expecting true or false)", relpipe::cli::CLI::EXIT_CODE_BAD_CLI_ARGUMENTS);
-	}
-
 	relpipe::writer::TypeId parseTypeId(const string_t& value) {
 		using t = relpipe::writer::TypeId;
 		if (value == L"string") return t::STRING;
@@ -83,7 +77,7 @@
 				else if (option == OPTION_AFTER_RECORDS) currentRelation.guileAfterRecords = readNext(arguments, i);
 				else if (option == OPTION_FOR_EACH) currentRelation.guileForEach = readNext(arguments, i);
 				else if (option == OPTION_WHERE) currentRelation.guileWhere = readNext(arguments, i);
-				else if (option == OPTION_DROP) currentRelation.drop = parseBoolean(readNext(arguments, i), option);
+				else if (option == OPTION_DROP) currentRelation.drop = true;
 				else if (option == OPTION_RELATION) {
 					addRelation(c, currentRelation); // previous relation
 					currentRelation.relation = readNext(arguments, i);
diff -r c9fece435aa2 -r 82bd0f57a889 src/Configuration.h
--- a/src/Configuration.h	Tue Feb 05 12:14:58 2019 +0100
+++ b/src/Configuration.h	Tue Feb 05 12:41:54 2019 +0100
@@ -75,7 +75,6 @@
 	 */
 	std::vector<DefinitionRecipe> definitions;
 
-	// TODO: --relation … --drop – will execute --for-each, but no output will be generated for this relation
 	// TODO: --create t2 3 a integer b boolean '…guile…' – allow creating new relations? Or allow calling startRelation() and attribute() from Guile?
 
 	virtual ~Configuration() {
diff -r c9fece435aa2 -r 82bd0f57a889 src/GuileHandler.h
--- a/src/GuileHandler.h	Tue Feb 05 12:14:58 2019 +0100
+++ b/src/GuileHandler.h	Tue Feb 05 12:41:54 2019 +0100
@@ -190,7 +190,7 @@
 			for (DefinitionRecipe definition : currentRelationConfiguration->definitions) undefineGuileVariable(definition.name);
 		}
 		for (auto attribute : currentReaderMetadata) undefineGuileVariable(attribute.getAttributeName());
-		
+
 		for (DefinitionRecipe definition : configuration.definitions) defineGuileVariable(definition);
 
 		currentRelationConfiguration = nullptr;
@@ -211,7 +211,7 @@
 			for (AttributeMetadata readerMetadata : attributes) currentWriterMetadata.push_back({readerMetadata.getAttributeName(), relationalWriter->toTypeId(readerMetadata.getTypeName())});
 		}
 
-		relationalWriter->startRelation(name, currentWriterMetadata, true);
+		if (!currentRelationConfiguration || !currentRelationConfiguration->drop) relationalWriter->startRelation(name, currentWriterMetadata, true);
 
 		if (currentRelationConfiguration) {
 			// TODO: better variable name, object, function?
@@ -230,7 +230,7 @@
 			if (currentAttributeIndex > 0 && currentAttributeIndex % currentReaderMetadata.size() == 0) {
 				evalGuileCode(currentRelationConfiguration->guileForEach);
 				includeCurrentRecord = scm_to_bool(evalGuileCode(currentRelationConfiguration->guileWhere, SCM_BOOL_T));
-				if (includeCurrentRecord) for (auto attribute : currentWriterMetadata) writeGuileValueToAttribute(attribute);
+				if (includeCurrentRecord && !currentRelationConfiguration->drop) for (auto attribute : currentWriterMetadata) writeGuileValueToAttribute(attribute);
 				includeCurrentRecord = false;
 			}