From 3a42a6911369ffb9a894019950a8e8ec5ffa89bf Mon Sep 17 00:00:00 2001
From: Chen22 <jingchen2222@gmail.com>
Date: Mon, 13 Dec 2021 14:14:40 -0800
Subject: [PATCH] feat: support show variables

---
 zetasql/parser/bison_parser.y     | 14 ++++++++++++++
 zetasql/parser/flex_tokenizer.l   |  3 +++
 zetasql/parser/keywords.cc        |  3 +++
 zetasql/parser/testdata/show.test | 24 ++++++++++++++++++++++++
 4 files changed, 44 insertions(+)

diff --git a/zetasql/parser/bison_parser.y b/zetasql/parser/bison_parser.y
index 46cc0b0fd..053251d54 100644
--- a/zetasql/parser/bison_parser.y
+++ b/zetasql/parser/bison_parser.y
@@ -840,6 +840,7 @@ using zetasql::ASTDropStatement;
 %token KW_FORMAT "FORMAT"
 %token KW_FUNCTION "FUNCTION"
 %token KW_GENERATED "GENERATED"
+%token KW_GLOBAL "GLOBAL"
 %token KW_GRANT "GRANT"
 %token KW_GROUP_ROWS "GROUP_ROWS"
 %token KW_HIDDEN "HIDDEN"
@@ -905,6 +906,7 @@ using zetasql::ASTDropStatement;
 %token KW_SCHEMA "SCHEMA"
 %token KW_SEARCH "SEARCH"
 %token KW_SECURITY "SECURITY"
+%token KW_SESSION "SESSION"
 %token KW_SHOW "SHOW"
 %token KW_SIMPLE "SIMPLE"
 %token KW_SOURCE "SOURCE"
@@ -934,6 +936,7 @@ using zetasql::ASTDropStatement;
 %token KW_USE "USE"
 %token KW_VALUE "VALUE"
 %token KW_VALUES "VALUES"
+%token KW_VARIABLES "VARIABLES"
 %token KW_VOLATILE "VOLATILE"
 %token KW_VIEW "VIEW"
 %token KW_VIEWS "VIEWS"
@@ -3566,6 +3569,14 @@ show_target:
     {
       $$ = parser->MakeIdentifier(@$, "PROCEDURE STATUS");
     }
+  | "GLOBAL" "VARIABLES"
+    {
+      $$ = parser->MakeIdentifier(@$, "GLOBAL VARIABLES");
+    }
+  | "SESSION" "VARIABLES"
+    {
+      $$ = parser->MakeIdentifier(@$, "SESSION VARIABLES");
+    }
   | identifier
     {
       $$ = $1;
@@ -7390,6 +7401,7 @@ keyword_as_identifier:
     | "FORMAT"
     | "FUNCTION"
     | "GENERATED"
+    | "GLOBAL"
     | "GRANT"
     | "GROUP_ROWS"
     | "HIDDEN"
@@ -7455,6 +7467,7 @@ keyword_as_identifier:
     | "SCHEMA"
     | "SEARCH"
     | "SECURITY"
+    | "SESSION"
     | "SHOW"
     | "SIMPLE"
     | "SOURCE"
@@ -7484,6 +7497,7 @@ keyword_as_identifier:
     | "USE"
     | "VALUE"
     | "VALUES"
+    | "VARIABLES"
     | "VIEW"
     | "VIEWS"
     | "VOLATILE"
diff --git a/zetasql/parser/flex_tokenizer.l b/zetasql/parser/flex_tokenizer.l
index c9cfc31b5..ecb741abd 100644
--- a/zetasql/parser/flex_tokenizer.l
+++ b/zetasql/parser/flex_tokenizer.l
@@ -469,6 +469,7 @@ from { return BisonParserImpl::token::KW_FROM; }
 full { return BisonParserImpl::token::KW_FULL; }
 function { return BisonParserImpl::token::KW_FUNCTION; }
 generated { return BisonParserImpl::token::KW_GENERATED; }
+global { return BisonParserImpl::token::KW_GLOBAL; }
 grant { return BisonParserImpl::token::KW_GRANT; }
 group { return BisonParserImpl::token::KW_GROUP; }
 group_rows { return BisonParserImpl::token::KW_GROUP_ROWS; }
@@ -603,6 +604,7 @@ safe_cast { return BisonParserImpl::token::KW_SAFE_CAST; }
 schema { return BisonParserImpl::token::KW_SCHEMA; }
 search { return BisonParserImpl::token::KW_SEARCH; }
 security { return BisonParserImpl::token::KW_SECURITY; }
+session { return BisonParserImpl::token::KW_SESSION; }
 select { return BisonParserImpl::token::KW_SELECT; }
 set { return BisonParserImpl::token::KW_SET; }
 show { return BisonParserImpl::token::KW_SHOW; }
@@ -646,6 +648,7 @@ use { return BisonParserImpl::token::KW_USE; }
 using { return BisonParserImpl::token::KW_USING; }
 value { return BisonParserImpl::token::KW_VALUE; }
 values { return BisonParserImpl::token::KW_VALUES; }
+variables { return BisonParserImpl::token::KW_VARIABLES; }
 view { return BisonParserImpl::token::KW_VIEW; }
 views { return BisonParserImpl::token::KW_VIEWS; }
 volatile { return BisonParserImpl::token::KW_VOLATILE; }
diff --git a/zetasql/parser/keywords.cc b/zetasql/parser/keywords.cc
index d32cda9b5..5176f592b 100644
--- a/zetasql/parser/keywords.cc
+++ b/zetasql/parser/keywords.cc
@@ -146,6 +146,7 @@ constexpr KeywordInfoPOD kAllKeywords[] = {
     {"full", KW_FULL, KeywordInfo::kReserved},
     {"function", KW_FUNCTION},
     {"generated", KW_GENERATED},
+    {"global", KW_GLOBAL},
     {"grant", KW_GRANT},
     {"group", KW_GROUP, KeywordInfo::kReserved},
     {"group_rows", KW_GROUP_ROWS},
@@ -261,6 +262,7 @@ constexpr KeywordInfoPOD kAllKeywords[] = {
     {"search", KW_SEARCH},
     {"security", KW_SECURITY},
     {"select", KW_SELECT, KeywordInfo::kReserved},
+    {"session", KW_SESSION},
     {"set", KW_SET, KeywordInfo::kReserved},
     {"show", KW_SHOW},
     {"simple", KW_SIMPLE},
@@ -301,6 +303,7 @@ constexpr KeywordInfoPOD kAllKeywords[] = {
     {"using", KW_USING, KeywordInfo::kReserved},
     {"value", KW_VALUE},
     {"values", KW_VALUES},
+    {"variables", KW_VARIABLES},
     {"volatile", KW_VOLATILE},
     {"view", KW_VIEW},
     {"views", KW_VIEWS},
diff --git a/zetasql/parser/testdata/show.test b/zetasql/parser/testdata/show.test
index 72434c5e8..c0c505b5a 100644
--- a/zetasql/parser/testdata/show.test
+++ b/zetasql/parser/testdata/show.test
@@ -126,6 +126,14 @@ ShowStatement [0-9]
 SHOW JOBS
 ==
 
+show VARIABLES;
+--
+ShowStatement [0-14]
+  Identifier(VARIABLES) [5-14]
+--
+SHOW VARIABLES
+==
+
 show VARIABLES like 'server_name';
 --
 ShowStatement [0-33]
@@ -135,6 +143,22 @@ ShowStatement [0-33]
 SHOW VARIABLES LIKE 'server_name'
 ==
 
+show GLOBAL VARIABLES;
+--
+ShowStatement [0-21]
+  Identifier(`GLOBAL VARIABLES`) [5-21]
+--
+SHOW `GLOBAL VARIABLES`
+==
+
+show SESSION VARIABLES;
+--
+ShowStatement [0-22]
+  Identifier(`SESSION VARIABLES`) [5-22]
+--
+SHOW `SESSION VARIABLES`
+==
+
 show TABLES from adwords like b'abc%';
 --
 ERROR: Syntax error: Expected string literal but got bytes literal b'abc%' [at 1:31]