From 3705bcc9bc8c726a60c1eaa1d29cd1d240c0268a Mon Sep 17 00:00:00 2001
From: Evgeniy Filatov <efilatov@geeksforless.net>
Date: Thu, 2 Aug 2018 17:57:16 +0300
Subject: [PATCH] added helper function that joins vectors of strings,
 refactored suggestions formattingi function to use it

---
 libdevcore/StringUtils.cpp      | 14 ++++--------
 libdevcore/StringUtils.h        | 39 +++++++++++++++++++++++++++++++++
 test/libdevcore/StringUtils.cpp | 18 +++++++++++++++
 3 files changed, 61 insertions(+), 10 deletions(-)

diff --git a/libdevcore/StringUtils.cpp b/libdevcore/StringUtils.cpp
index 2ff86bd56..01bdc6756 100644
--- a/libdevcore/StringUtils.cpp
+++ b/libdevcore/StringUtils.cpp
@@ -85,17 +85,11 @@ size_t dev::stringDistance(string const& _str1, string const& _str2)
 
 string dev::quotedAlternativesList(vector<string> const& suggestions)
 {
-	if (suggestions.empty())
-		return "";
-	if (suggestions.size() == 1)
-		return "\"" + suggestions.front() + "\"";
+	vector<string> quotedSuggestions;
 
-	string choices = "\"" + suggestions.front() + "\"";
-	for (size_t i = 1; i + 1 < suggestions.size(); ++i)
-		choices += ", \"" + suggestions[i] + "\"";
+	for (auto& suggestion: suggestions)
+		quotedSuggestions.push_back("\"" + suggestion + "\"");
 
-	choices += " or \"" + suggestions.back() + "\"";
-
-	return choices;
+	return joinHumanReadable(quotedSuggestions, ", ", " or ");
 }
 
diff --git a/libdevcore/StringUtils.h b/libdevcore/StringUtils.h
index acd93e326..4fb5a748c 100644
--- a/libdevcore/StringUtils.h
+++ b/libdevcore/StringUtils.h
@@ -36,4 +36,43 @@ size_t stringDistance(std::string const& _str1, std::string const& _str2);
 // Return a string having elements of suggestions as quoted, alternative suggestions. e.g. "a", "b" or "c"
 std::string quotedAlternativesList(std::vector<std::string> const& suggestions);
 
+/// Joins collection of strings into one string with separators between, last separator can be different.
+/// @param _list collection of strings to join
+/// @param _separator defaults to ", "
+/// @param _lastSeparator (optional) will be used to separate last two strings instead of _separator
+/// @example join(vector<string>{"a", "b", "c"}, "; ", " or ") == "a; b or c"
+template<class T>
+std::string joinHumanReadable
+(
+	T const& _list,
+	std::string const& _separator = ", ",
+	std::string const& _lastSeparator = ""
+)
+{
+	auto it = begin(_list);
+	auto itEnd = end(_list);
+
+	std::string result;
+
+	// append first string
+	if (it != itEnd)
+	{
+		result += *it;
+		++it;
+	}
+
+	for (;it != itEnd; ++it)
+	{
+		if ((next(it) == itEnd) && !_lastSeparator.empty())
+			result += _lastSeparator; // last iteration
+		else
+			result += _separator;
+
+		// append string
+		result += *it;
+	}
+
+	return result;
+}
+
 }
diff --git a/test/libdevcore/StringUtils.cpp b/test/libdevcore/StringUtils.cpp
index 9ee93d02a..94f1b7531 100644
--- a/test/libdevcore/StringUtils.cpp
+++ b/test/libdevcore/StringUtils.cpp
@@ -81,6 +81,24 @@ BOOST_AUTO_TEST_CASE(test_alternatives_list)
 	BOOST_CHECK_EQUAL(quotedAlternativesList(strings), "\"a\", \"b\", \"c\" or \"d\"");
 }
 
+BOOST_AUTO_TEST_CASE(test_human_readable_join)
+{
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({})), "");
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({"a"})), "a");
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({"a", "b"})), "a, b");
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({"a", "b", "c"})), "a, b, c");
+
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({}), "; "), "");
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({"a"}), "; "), "a");
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({"a", "b"}), "; "), "a; b");
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({"a", "b", "c"}), "; "), "a; b; c");
+
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({}), "; ", " or "), "");
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({"a"}), "; ", " or "), "a");
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({"a", "b"}), "; ", " or "), "a or b");
+	BOOST_CHECK_EQUAL(joinHumanReadable(vector<string>({"a", "b", "c"}), "; ", " or "), "a; b or c");
+}
+
 
 BOOST_AUTO_TEST_SUITE_END()