From 61877a40e5db127bf73ccd4799dabc2b15d6a82c Mon Sep 17 00:00:00 2001
From: ltrk2 <107155950+ltrk2@users.noreply.github.com>
Date: Mon, 12 Sep 2022 10:13:18 -0700
Subject: [PATCH] Simplify KQL trim functions to avoid aliases

---
 .../KustoFunctions/KQLStringFunctions.cpp     | 31 +++++++------------
 .../tests/KQL/gtest_KQL_StringFunctions.cpp   |  8 ++---
 2 files changed, 16 insertions(+), 23 deletions(-)

diff --git a/src/Parsers/Kusto/KustoFunctions/KQLStringFunctions.cpp b/src/Parsers/Kusto/KustoFunctions/KQLStringFunctions.cpp
index 2085918ada0c..f37563ecccd3 100644
--- a/src/Parsers/Kusto/KustoFunctions/KQLStringFunctions.cpp
+++ b/src/Parsers/Kusto/KustoFunctions/KQLStringFunctions.cpp
@@ -547,48 +547,41 @@ bool Translate::convertImpl(String & out,IParser::Pos & pos)
     return true;
 }
 
-bool Trim::convertImpl(String & out,IParser::Pos & pos)
+bool Trim::convertImpl(String & out, IParser::Pos & pos)
 {
     const String fn_name = getKQLFunctionName(pos);
     if (fn_name.empty())
         return false;
 
-    ++pos;
-    String regex = getConvertedArgument(fn_name, pos);
-    ++pos;
-    String  source = getConvertedArgument(fn_name, pos);
-    String ltrim = std::format("if ((replaceRegexpOne(concat('start_random_str_', {0}) as srcl, concat('start_random_str_', {1}),'') as dstl) = srcl, {0}, dstl)", source, regex);
-    out = std::format("if ((replaceRegexpOne(concat({0}, '_end_random_str') as srcr, concat({1}, '_end_random_str'),'') as dstr) = srcr, {0}, dstr)", ltrim, regex);
+    const auto regex = getArgument(fn_name, pos);
+    const auto source = getArgument(fn_name, pos);
+    out = kqlCallToExpression("trim_start", {regex, std::format("trim_end({0}, {1})", regex, source)}, pos.max_depth);
 
     return true;
 }
 
-bool TrimEnd::convertImpl(String & out,IParser::Pos & pos)
+bool TrimEnd::convertImpl(String & out, IParser::Pos & pos)
 {
     const String fn_name = getKQLFunctionName(pos);
     if (fn_name.empty())
         return false;
 
-    ++pos;
-    String regex = getConvertedArgument(fn_name, pos);
-    ++pos;
-    String  source = getConvertedArgument(fn_name, pos);
-    out = std::format("if ((replaceRegexpOne(concat({0}, '_end_random_str') as src, concat({1},'_end_random_str'),'') as dst) = src, {0}, dst)", source, regex);
+    const auto regex = getArgument(fn_name, pos);
+    const auto source = getArgument(fn_name, pos);
+    out = std::format("replaceRegexpOne({0}, concat({1}, '$'), '')", source, regex);
 
     return true;
 }
 
-bool TrimStart::convertImpl(String & out,IParser::Pos & pos)
+bool TrimStart::convertImpl(String & out, IParser::Pos & pos)
 {
     const String fn_name = getKQLFunctionName(pos);
     if (fn_name.empty())
         return false;
 
-    ++pos;
-    String regex = getConvertedArgument(fn_name, pos);
-    ++pos;
-    String  source = getConvertedArgument(fn_name, pos);
-    out = std::format("if ((replaceRegexpOne(concat('start_random_str_', {0}) as src, concat('start_random_str_', {1}),'') as dst) = src, {0}, dst)", source, regex);
+    const auto regex = getArgument(fn_name, pos);
+    const auto source = getArgument(fn_name, pos);
+    out = std::format("replaceRegexpOne({0}, concat('^', {1}), '')", source, regex);
 
     return true;
 }
diff --git a/src/Parsers/tests/KQL/gtest_KQL_StringFunctions.cpp b/src/Parsers/tests/KQL/gtest_KQL_StringFunctions.cpp
index ea010210ea14..12ad5c6d563c 100644
--- a/src/Parsers/tests/KQL/gtest_KQL_StringFunctions.cpp
+++ b/src/Parsers/tests/KQL/gtest_KQL_StringFunctions.cpp
@@ -2,7 +2,7 @@
 
 #include <Parsers/Kusto/ParserKQLQuery.h>
 
-INSTANTIATE_TEST_SUITE_P(ParserKQLQuery, ParserTest,
+INSTANTIATE_TEST_SUITE_P(ParserKQLQuery_String, ParserTest,
     ::testing::Combine(
         ::testing::Values(std::make_shared<DB::ParserKQLQuery>()),
         ::testing::ValuesIn(std::initializer_list<ParserTestCase>{
@@ -36,15 +36,15 @@ INSTANTIATE_TEST_SUITE_P(ParserKQLQuery, ParserTest,
         },
         {
             "print trim_start('[^\\w]+', strcat('-  ','Te st1','// $'))",
-            "SELECT if((replaceRegexpOne(concat('start_random_str_', concat('-  ', 'Te st1', '// $')) AS src, concat('start_random_str_', '[^\\\\w]+'), '') AS dst) = src, concat('-  ', 'Te st1', '// $'), dst)"
+            "SELECT replaceRegexpOne(concat('-  ', 'Te st1', '// $'), concat('^', '[^\\\\w]+'), '')"
         },
         {
             "print trim_end('.com', 'bing.com')",
-            "SELECT if((replaceRegexpOne(concat('bing.com', '_end_random_str') AS src, concat('.com', '_end_random_str'), '') AS dst) = src, 'bing.com', dst)"
+            "SELECT replaceRegexpOne('bing.com', concat('.com', '$'), '')"
         },
         {
             "print trim('--', '--https://bing.com--')",
-            "SELECT if((replaceRegexpOne(concat(if((replaceRegexpOne(concat('start_random_str_', '--https://bing.com--') AS srcl, concat('start_random_str_', '--'), '') AS dstl) = srcl, '--https://bing.com--', dstl), '_end_random_str') AS srcr, concat('--', '_end_random_str'), '') AS dstr) = srcr, if(dstl = srcl, '--https://bing.com--', dstl), dstr)"
+            "SELECT replaceRegexpOne(replaceRegexpOne('--https://bing.com--', concat('--', '$'), ''), concat('^', '--'), '')"
         },
         {
             "print bool(1)",