initial commit

22 files changed, 1457 insertions, 0 deletions

diff --git a/.clang-format b/.clang-format
new file mode 100644
index 0000000..497ab0b
--- /dev/null
+++ b/.clang-format
@@ -0,0 +1,36 @@
+#基于哪个配置文件
+BasedOnStyle: LLVM
+#指针的*的挨着哪边
+PointerAlignment: Left
+#缩进宽度
+IndentWidth: 4
+#连续的空行保留几行
+MaxEmptyLinesToKeep: 1
+#是否允许短方法单行
+AllowShortFunctionsOnASingleLine: true
+#是否允许短if单行 If true, if (a) return; 可以放到同一行
+AllowShortIfStatementsOnASingleLine: true
+#注释对齐
+AlignTrailingComments: true
+#换行的时候对齐操作符
+#AlignOperands: true
+#多行声明语句按照=对齐
+AlignConsecutiveDeclarations: true
+#连续的赋值语句以 = 为中心对齐
+AlignConsecutiveAssignments: false
+AlignConsecutiveDeclarations: false
+#等号两边的空格
+SpaceBeforeAssignmentOperators: true
+#缩进
+IndentWrappedFunctionNames: true
+#在block从空行开始
+KeepEmptyLinesAtTheStartOfBlocks: true
+#在构造函数初始化时按逗号断行，并以冒号对齐
+BreakConstructorInitializersBeforeComma: true
+#函数参数换行
+AllowAllParametersOfDeclarationOnNextLine: true
+#括号后添加空格
+SpaceAfterCStyleCast: true
+#tab键盘的宽度
+TabWidth: 4
+UseTab: Never
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5acb669
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+build
+.vscode
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..473eb3d
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,41 @@
+cmake_minimum_required(VERSION 3.4)
+project(pcc)
+
+find_package(LLVM REQUIRED CONFIG)
+include_directories(${LLVM_INCLUDE_DIRS})
+add_definitions(${LLVM_DEFINITIONS})
+
+find_package(BISON REQUIRED)
+find_package(FLEX REQUIRED)
+
+bison_target(pcc_parser Parser.y ${CMAKE_CURRENT_BINARY_DIR}/Parser.cc)
+flex_target(pcc_lexer Lexer.l ${CMAKE_CURRENT_BINARY_DIR}/Lexer.cc)
+add_flex_bison_dependency(pcc_lexer pcc_parser)
+
+add_definitions(-DPCC_OSNAME="${CMAKE_SYSTEM}")
+
+set(PCC_SOURCE
+    Context.cc
+    Driver.cc
+    Lexer.cc
+    Log.cc
+    main.cc
+    Parser.cc
+    Version.cc)
+
+list(APPEND PCC_SOURCE
+    node/BaseNode.cc
+    node/LiteralNode.cc)
+
+list(APPEND PCC_SOURCE
+    ${BISON_pcc_parser_OUTPUT}
+    ${FLEX_pcc_lexer_OUTPUT})
+
+add_executable(pcc ${PCC_SOURCE})
+target_include_directories(pcc PRIVATE
+    ${CMAKE_SOURCE_DIR}
+    ${CMAKE_SOURCE_DIR}/node
+    ${CMAKE_CURRENT_BINARY_DIR})
+
+llvm_map_components_to_libnames(llvm_libs support core irreader all)
+target_link_libraries(pcc ${llvm_libs})
diff --git a/COPYING b/COPYING
new file mode 100644
index 0000000..623b625
--- /dev/null
+++ b/COPYING
@@ -0,0 +1,340 @@
+		    GNU GENERAL PUBLIC LICENSE
+		       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+     51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+			    Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+		    GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
+    stating that you changed the files and the date of any change.
+
+    b) You must cause any work that you distribute or publish, that in
+    whole or in part contains or is derived from the Program or any
+    part thereof, to be licensed as a whole at no charge to all third
+    parties under the terms of this License.
+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
+    announcement including an appropriate copyright notice and a
+    notice that there is no warranty (or else, saying that you provide
+    a warranty) and that users may redistribute the program under
+    these conditions, and telling the user how to view a copy of this
+    License.  (Exception: if the Program itself is interactive but
+    does not normally print such an announcement, your work based on
+    the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of Sections
+    1 and 2 above on a medium customarily used for software interchange; or,
+
+    b) Accompany it with a written offer, valid for at least three
+    years, to give any third party, for a charge no more than your
+    cost of physically performing source distribution, a complete
+    machine-readable copy of the corresponding source code, to be
+    distributed under the terms of Sections 1 and 2 above on a medium
+    customarily used for software interchange; or,
+
+    c) Accompany it with the information you received as to the offer
+    to distribute corresponding source code.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form with such
+    an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable.  However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+  7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+			    NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+		     END OF TERMS AND CONDITIONS
+
+	    How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) year  name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Library General
+Public License instead of this License.
diff --git a/Context.cc b/Context.cc
new file mode 100644
index 0000000..ee88544
--- /dev/null
+++ b/Context.cc
@@ -0,0 +1,11 @@
+#include <llvm/IR/LLVMContext.h>
+
+#include "Context.hh"
+
+namespace pcc {
+llvm::LLVMContext GlobalContext;
+
+Context::Context(const char* name)
+    : builder_(GlobalContext)
+    , module_(name, GlobalContext) {}
+} // namespace pcc
diff --git a/Context.hh b/Context.hh
new file mode 100644
index 0000000..bc66632
--- /dev/null
+++ b/Context.hh
@@ -0,0 +1,22 @@
+#ifndef PCC_CONTEXT_H
+#define PCC_CONTEXT_H
+
+#include <llvm/IR/IRBuilder.h>
+#include <llvm/IR/Module.h>
+
+namespace pcc {
+class Driver;
+class Context {
+  public:
+    Context(const char* name);
+
+  private:
+    llvm::IRBuilder<> builder_;
+    llvm::Module module_;
+    friend class Driver;
+};
+
+extern llvm::LLVMContext GlobalContext;
+} // namespace pcc
+
+#endif
diff --git a/Driver.cc b/Driver.cc
new file mode 100644
index 0000000..3fefd8c
--- /dev/null
+++ b/Driver.cc
@@ -0,0 +1,21 @@
+#include "Driver.hh"
+
+namespace pcc {
+Driver::Driver(Context* context)
+    : context_(context) {}
+
+Driver::~Driver() {}
+
+void Driver::Parse(const std::string& filename) {
+    if (StartLexer(filename) != 0) {
+        return;
+    }
+    Parser parser(*this);
+    parser.parse();
+    StopLexer();
+}
+
+llvm::Module* Driver::GetModule() { return &context_->module_; }
+
+llvm::IRBuilder<>* Driver::GetBuilder() { return &context_->builder_; }
+} // namespace pcc
diff --git a/Driver.hh b/Driver.hh
new file mode 100644
index 0000000..5fc5d83
--- /dev/null
+++ b/Driver.hh
@@ -0,0 +1,28 @@
+#ifndef PCC_DRIVER_H
+#define PCC_DRIVER_H
+
+#include <cstdio>
+
+#include "Context.hh"
+#include "Parser.hh"
+
+#define YY_DECL pcc::Parser::symbol_type yylex(pcc::Driver& driver)
+
+YY_DECL;
+
+namespace pcc {
+class Driver {
+  public:
+    Driver(Context* context);
+    ~Driver();
+    int StartLexer(const std::string& filename);
+    void StopLexer();
+    void Parse(const std::string& filename);
+    llvm::Module* GetModule();
+    llvm::IRBuilder<>* GetBuilder();
+
+    Context* context_;
+};
+} // namespace pcc
+
+#endif
diff --git a/Lexer.l b/Lexer.l
new file mode 100755
index 0000000..fad699f
--- /dev/null
+++ b/Lexer.l
@@ -0,0 +1,198 @@
+%{
+#include <map>
+#include <cctype>
+#include <cstdlib>
+#include <iostream>
+#include <algorithm>
+
+#include "Log.hh"
+#include "Driver.hh"
+
+using token=pcc::Parser::token;
+
+namespace pcc {
+    class Lexer;
+    char ToLower(char c){
+        return static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+    }
+}
+
+%}
+
+%option nodefault
+%option never-interactive
+%option nounistd
+%option case-insensitive
+%option noyywrap nounput noinput
+
+decimal         ([1-9][0-9]*)|0
+octal           0[0-7]*
+hexadecimal     0[xX][0-9a-fA-F]
+
+integer         [+-]?({decimal}|{octal}|{hexadecimal})
+
+real_exp        [0-9]*(\.[0-9]*)?[eE]{decimal}
+real_noexp      [0-9]*\.[0-9]*
+
+real            [+-]?({real_exp}|{real_noexp})
+
+char            [0-9a-zA-Z_{}[\]#()<>%:;.?*+\-/^&|~!=,\\" \t\n\v\f]
+escaped_char    \\[\'?\\abfnrtv]
+hex_char        \\x[0-9a-fA-F]{1,2}
+oct_char        \\[0-7]{1,3}
+
+string          '({char}|{escaped_char}|{hex_char}|{oct_char}|\\')*'
+
+identifier      [a-z][0-9a-z]*
+
+white           [\t\f\n\r ]
+
+%%
+
+":="        {return token::ASSIGN;}
+":"         {return token::COLON;}
+";"         {return token::SEMICOLON;}
+"."         {return token::DOT;}
+"["         {return token::LBRACKET;}
+"]"         {return token::RBRACKET;}
+"("         {return token::LPARENTHESIS;}
+")"         {return token::RPARENTHESIS;}
+
+"+"         {return token::ADD;}
+"-"         {return token::SUB;}
+"*"         {return token::MUL;}
+"/"         {return token::REAL_DIV;}
+"div"       {return token::DIV;}
+"mod"       {return token::MOD;}
+"**"        {return token::EXP;}
+
+"and"       {return token::AND;}
+"not"       {return token::NOT;}
+"or"        {return token::OR;}
+"xor"       {return token::XOR;}
+
+"<"         {return token::LT;}
+"<="        {return token::LE;}
+">"         {return token::GT;}
+">="        {return token::GE;}
+"="         {return token::EQ;}
+"<>"        {return token::NE;}
+
+"begin"     {return token::BEGINS;}
+"end"       {return token::ENDS;}
+"program"   {return token::PROGRAM;}
+"function"  {return token::FUNCTION;}
+"const"     {return token::CONST;}
+"var"       {return token::VAR;}
+"if"        {return token::IF;}
+"then"      {return token::THEN;}
+"else"      {return token::ELSE;}
+"while"     {return token::WHILE;}
+"do"        {return token::DO;}
+"integer"   {return token::INTEGER;}
+"boolean"   {return token::BOOLEAN;}
+"char"      {return token::CHAR;}
+"real"      {return token::REAL;}
+"string"    {return token::STRING;}
+"true"      {return token::TRUE;}
+"false"     {return token::FALSE;}
+
+{integer} {
+    int number = std::strtol(yytext, NULL, 0);
+    return pcc::Parser::make_INTEGER_LITERAL(number);
+}
+
+{real} {
+    float number = std::strtof(yytext, NULL);
+    return pcc::Parser::make_REAL_LITERAL(number);
+}
+
+{string} {
+    static std::map<char,char> escape_map={
+        {'\'','\''},
+        {'?','\?'},
+        {'\\','\\'},
+        {'a','\a'},
+        {'b','\b'},
+        {'f','\f'},
+        {'n','\n'},
+        {'r','\r'},
+        {'t','\t'},
+        {'v','\v'}
+    };
+    char *str = new char[yyleng];
+    char *p = str;
+    int i = 1;
+    while(i<yyleng-1){
+        if(yytext[i]!='\\'){
+            *p++=yytext[i];
+            i++;
+        }
+        else if(yytext[i+1]=='x'){
+            char c[3], *cend;
+            c[0]=yytext[i+2];
+            if(i+3<yyleng-1){
+                c[1]=yytext[i+3];
+                c[2]='\0';
+            } else {
+                c[1]='\0';
+            }
+            *p++=(char)std::strtol(c,&cend,16);
+            i+=(int)(cend-c)+2;
+        }
+        else if(yytext[i+1]>='0' && yytext[i+1]<='7'){
+            char c[4], *cend;
+            c[0]=yytext[i+1];
+            if(i+3<yyleng-1){
+                c[1]=yytext[i+2];
+                c[2]=yytext[i+3];
+                c[3]='\0';
+            }
+            else if(i+3<yyleng){
+                c[1]=yytext[i+2];
+                c[2]='\0';
+            }
+            else {
+                c[1]='\0';
+            }
+            *p++=(char)std::strtol(c,&cend,8);
+            i+=(int)(cend-c)+1;
+        }
+        else {
+            *p++=escape_map[yytext[i+1]];
+            i+=2;
+        }
+    }
+    *p++='\0';
+    return pcc::Parser::make_STRING_LITERAL(str);
+}
+
+{identifier} {
+    char *name = new char[yyleng];
+    std::transform(yytext, yytext+yyleng, name, pcc::ToLower);
+    return pcc::Parser::make_IDENTIFIER(yytext);
+}
+
+{white} {}
+
+. {
+    std::cerr<<"ERROR";
+}
+
+%%
+
+namespace pcc {
+    int Driver::StartLexer(const std::string &filename)
+    {
+        yyin=std::fopen(filename.c_str(),"r");
+        if(yyin==NULL){
+            Log(PCC_ERROR, "Failed to open file %s", filename.c_str());
+            return -1;
+        }
+        return 0;
+    }
+
+    void Driver::StopLexer(){
+        std::fclose(yyin);
+    }
+}
diff --git a/Log.cc b/Log.cc
new file mode 100644
index 0000000..666fdab
--- /dev/null
+++ b/Log.cc
@@ -0,0 +1,31 @@
+#include "Log.hh"
+
+namespace pcc {
+void Log(LogLevel level, const char* format, ...) {
+    va_list va;
+    va_start(va, format);
+    if (CurrentLogLevel <= level) {
+        switch (level) {
+        case PCC_ERROR:
+            fprintf(stderr, "[ERROR] ");
+            break;
+        case PCC_WARNING:
+            fprintf(stderr, "[WARNING] ");
+            break;
+        case PCC_INFO:
+            fprintf(stderr, "[INFO] ");
+            break;
+        case PCC_DEBUG:
+            fprintf(stderr, "[DEBUG] ");
+            break;
+        }
+        std::vfprintf(stderr, format, va);
+        std::fputc('\n', stderr);
+    }
+    va_end(va);
+}
+
+LogLevel CurrentLogLevel = PCC_ERROR;
+
+void SetLogLevel(LogLevel level) { CurrentLogLevel = level; }
+} // namespace pcc
diff --git a/Log.hh b/Log.hh
new file mode 100644
index 0000000..dfb0cc9
--- /dev/null
+++ b/Log.hh
@@ -0,0 +1,17 @@
+#ifndef PCC_LOG_H
+#define PCC_LOG_H
+
+#include <cstdarg>
+#include <cstdio>
+
+namespace pcc {
+enum LogLevel { PCC_ERROR, PCC_WARNING, PCC_INFO, PCC_DEBUG };
+
+extern LogLevel CurrentLogLevel;
+
+void SetLogLevel(LogLevel level);
+
+void Log(LogLevel level, const char* format, ...);
+} // namespace pcc
+
+#endif
diff --git a/Parser.y b/Parser.y
new file mode 100644
index 0000000..bbad3fb
--- /dev/null
+++ b/Parser.y
@@ -0,0 +1,247 @@
+%language "c++"
+%require "3.2"
+
+%code requires {
+#include <string>
+
+namespace pcc {
+    class Driver;
+}
+}
+
+%param {pcc::Driver& driver}
+
+%code {
+#include "Driver.hh"
+}
+
+%define api.namespace {pcc}
+%define api.parser.class {Parser}
+%define api.value.type variant
+%define api.token.constructor
+%define parse.error verbose
+%define parse.assert
+
+%token COLON SEMICOLON COMMA DOT ASSIGN LBRACKET RBRACKET LPARENTHESIS RPARENTHESIS
+%token PROGRAM IDENTIFIER CONST VAR BEGINS ENDS FUNCTION
+%token IF THEN ELSE WHILE DO
+%token INTEGER BOOLEAN CHAR REAL STRING
+%token ADD SUB MUL REAL_DIV DIV MOD EXP LT LE GT GE EQ NE
+%token AND NOT OR XOR TRUE FALSE
+%token INTEGER_LITERAL REAL_LITERAL STRING_LITERAL
+
+%type <int> INTEGER_LITERAL
+%type <float> REAL_LITERAL
+%type <char*> STRING_LITERAL
+%type <char*> IDENTIFIER
+
+%%
+
+/* ==================[global part]================== */
+
+program
+    : program_decl global_decls function_decls
+    ;
+
+program_decl
+    : PROGRAM IDENTIFIER SEMICOLON
+    ;
+
+global_decls
+    : var_block
+    ;
+
+function_decls
+    : function_decls function_decl
+    |
+    ;
+
+/* ==================[var part]================== */
+
+var_block
+    : VAR var_decls SEMICOLON
+    ;
+
+var_decls
+    : var_decls SEMICOLON var_decl
+    | var_decl
+    ;
+
+var_decl
+    : vars COLON var_type
+    ;
+
+vars
+    : vars COMMA IDENTIFIER
+    | IDENTIFIER
+
+var_type
+    : INTEGER
+    | REAL
+    | BOOLEAN
+    | CHAR
+    | STRING
+    ;
+
+/* ==================[function part]================== */
+
+function_decl
+    : function_header function_body
+    ;
+
+function_header
+    : FUNCTION IDENTIFIER LPARENTHESIS var_decls RPARENTHESIS COLON var_type SEMICOLON
+    ;
+
+function_body
+    : var_block statement_block SEMICOLON
+    | statement_block SEMICOLON
+    ;
+
+/* ==================[statements part]================== */
+
+statements
+    : statements statement SEMICOLON
+    |
+    ;
+
+statement
+    : closed_statement
+    | open_statement
+    ;
+
+open_statement
+    : IF expression THEN statement
+    | IF expression THEN closed_statement ELSE open_statement
+    ;
+
+closed_statement
+    : normal_statement
+    | IF expression THEN closed_statement ELSE closed_statement
+    ;
+
+normal_statement
+    : statement_block
+    | empty_statement
+    | assign_statement
+    | while_statement
+    | expression_statement
+    ;
+
+statement_block
+    : BEGINS statements ENDS
+    ;
+
+empty_statement
+    :
+    ;
+
+assign_statement
+    : lvalue ASSIGN expression
+    ;
+
+while_statement
+    : WHILE expression DO statement
+    ;
+
+expression_statement
+    : function_call
+    ;
+
+/* ==================[expression part]================== */
+
+expression
+    : l1_expression l1_operator expression
+    | l1_expression
+    ;
+
+l1_expression
+    : l1_expression l2_operator l2_expression
+    | l2_expression
+    ;
+
+l2_expression
+    : l2_expression l3_operator l3_expression
+    | l3_expression
+    ;
+
+l3_expression
+    : l3_expression l4_operator l4_expression
+    | l4_expression
+
+l4_expression
+    : lvalue
+    | function_call
+    | literal
+    | LPARENTHESIS expression RPARENTHESIS
+    | l5_operator l4_expression
+    ;
+
+l1_operator
+    : LT
+    | LE
+    | GT
+    | GE
+    | EQ
+    | NE
+    ;
+
+l2_operator
+    : ADD
+    | SUB
+    | OR
+    | XOR
+    ;
+
+l3_operator
+    : MUL
+    | REAL_DIV
+    | DIV
+    | MOD
+    | AND
+    ;
+
+l4_operator
+    : EXP
+    ;
+
+l5_operator
+    : NOT
+    | ADD
+    | SUB
+    ;
+
+lvalue
+    : IDENTIFIER
+    | IDENTIFIER LBRACKET expression RBRACKET
+    | IDENTIFIER DOT IDENTIFIER
+    ;
+
+function_call
+    : IDENTIFIER LPARENTHESIS arguments RPARENTHESIS
+    | IDENTIFIER LPARENTHESIS RPARENTHESIS
+    ;
+
+arguments
+    : arguments COMMA expression
+    | expression
+    ;
+
+literal
+    : TRUE
+    | FALSE
+    | INTEGER_LITERAL
+    | REAL_LITERAL
+    | STRING_LITERAL
+    ;
+
+%%
+
+namespace pcc {
+
+    void Parser::error (const std::string& m)
+    {
+        std::cerr << m << '\n';
+    }
+
+}
diff --git a/Version.cc b/Version.cc
new file mode 100644
index 0000000..9b8be86
--- /dev/null
+++ b/Version.cc
@@ -0,0 +1,31 @@
+#include "Version.hh"
+
+namespace pcc {
+
+PCC_NORETURN void ShowVersion() {
+    std::cerr
+        << PCC_NAME " version " PCC_VERSION_STRING "\n"
+        << "Copyright (C) 2020 Hanjie Wu <nagi@zju.edu.cn>\n"
+           "Platform: " PCC_OSNAME "\n"
+           "Built on " __DATE__ " " __TIME__ "\n\n"
+           "This program is free software; you can redistribute it and/or "
+           "modify\n"
+           "it under the terms of the GNU General Public License as published "
+           "by\n"
+           "the Free Software Foundation; either version 2 of the License, or\n"
+           "(at your option) any later version."
+        << std::endl;
+    std::exit(0);
+}
+
+PCC_NORETURN void ShowHelp() {
+    std::cerr << PCC_NAME " version " PCC_VERSION_STRING "\n"
+              << "Usage: " PCC_NAME " [-vVh] file...\n"
+              << "    -v   Verbose mode.\n"
+                 "    -V   Show version and exit.\n"
+                 "    -h   Show this help and exit."
+              << std::endl;
+    std::exit(0);
+}
+
+} // namespace pcc
diff --git a/Version.hh b/Version.hh
new file mode 100644
index 0000000..5b3a7ff
--- /dev/null
+++ b/Version.hh
@@ -0,0 +1,27 @@
+#ifndef PCC_VERSION_H
+#define PCC_VERSION_H
+
+#include <cstdlib>
+#include <iostream>
+
+#define PCC_NAME "pcc"
+#define PCC_VERSION_STRING "0.1.0"
+
+#ifndef PCC_OSNAME
+#define PCC_OSNAME "unknown platform"
+#endif
+
+#ifdef _MSC_VER
+#define PCC_NORETURN __declspec(noreturn)
+#else
+#define PCC_NORETURN __attribute__((noreturn))
+#endif
+
+namespace pcc {
+
+PCC_NORETURN void ShowVersion();
+PCC_NORETURN void ShowHelp();
+
+} // namespace pcc
+
+#endif
diff --git a/getopt.c b/getopt.c
new file mode 100644
index 0000000..b5eebdf
--- /dev/null
+++ b/getopt.c
@@ -0,0 +1,223 @@
+/*******************************************************************************
+ * Copyright (c) 2012-2017, Kim Grasman <kim.grasman@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Kim Grasman nor the
+ *     names of contributors may be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL KIM GRASMAN BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ******************************************************************************/
+
+#include "getopt.h"
+
+#include <stddef.h>
+#include <string.h>
+
+char* optarg;
+int optopt;
+/* The variable optind [...] shall be initialized to 1 by the system. */
+int optind = 1;
+int opterr;
+
+static char* optcursor = NULL;
+
+/* Implemented based on [1] and [2] for optional arguments.
+   optopt is handled FreeBSD-style, per [3].
+   Other GNU and FreeBSD extensions are purely accidental.
+
+[1] http://pubs.opengroup.org/onlinepubs/000095399/functions/getopt.html
+[2] http://www.kernel.org/doc/man-pages/online/pages/man3/getopt.3.html
+[3]
+http://www.freebsd.org/cgi/man.cgi?query=getopt&sektion=3&manpath=FreeBSD+9.0-RELEASE
+*/
+int getopt(int argc, char* const argv[], const char* optstring) {
+    int optchar = -1;
+    const char* optdecl = NULL;
+
+    optarg = NULL;
+    opterr = 0;
+    optopt = 0;
+
+    /* Unspecified, but we need it to avoid overrunning the argv bounds. */
+    if (optind >= argc) goto no_more_optchars;
+
+    /* If, when getopt() is called argv[optind] is a null pointer, getopt()
+       shall return -1 without changing optind. */
+    if (argv[optind] == NULL) goto no_more_optchars;
+
+    /* If, when getopt() is called *argv[optind]  is not the character '-',
+       getopt() shall return -1 without changing optind. */
+    if (*argv[optind] != '-') goto no_more_optchars;
+
+    /* If, when getopt() is called argv[optind] points to the string "-",
+       getopt() shall return -1 without changing optind. */
+    if (strcmp(argv[optind], "-") == 0) goto no_more_optchars;
+
+    /* If, when getopt() is called argv[optind] points to the string "--",
+       getopt() shall return -1 after incrementing optind. */
+    if (strcmp(argv[optind], "--") == 0) {
+        ++optind;
+        goto no_more_optchars;
+    }
+
+    if (optcursor == NULL || *optcursor == '\0') optcursor = argv[optind] + 1;
+
+    optchar = *optcursor;
+
+    /* FreeBSD: The variable optopt saves the last known option character
+       returned by getopt(). */
+    optopt = optchar;
+
+    /* The getopt() function shall return the next option character (if one is
+       found) from argv that matches a character in optstring, if there is
+       one that matches. */
+    optdecl = strchr(optstring, optchar);
+    if (optdecl) {
+        /* [I]f a character is followed by a colon, the option takes an
+           argument. */
+        if (optdecl[1] == ':') {
+            optarg = ++optcursor;
+            if (*optarg == '\0') {
+                /* GNU extension: Two colons mean an option takes an
+                   optional arg; if there is text in the current argv-element
+                   (i.e., in the same word as the option name itself, for
+                   example,
+                   "-oarg"), then it is returned in optarg, otherwise optarg is
+                   set to zero. */
+                if (optdecl[2] != ':') {
+                    /* If the option was the last character in the string
+                       pointed to by an element of argv, then optarg shall
+                       contain the next element of argv, and optind shall be
+                       incremented by 2. If the resulting value of optind is
+                       greater than argc, this indicates a missing
+                       option-argument, and getopt() shall return an error
+                       indication.
+
+                       Otherwise, optarg shall point to the string following the
+                       option character in that element of argv, and optind
+                       shall be incremented by 1.
+                    */
+                    if (++optind < argc) {
+                        optarg = argv[optind];
+                    } else {
+                        /* If it detects a missing option-argument, it shall
+                           return the colon character ( ':' ) if the first
+                           character of optstring was a colon, or a
+                           question-mark character ( '?' ) otherwise.
+                        */
+                        optarg = NULL;
+                        optchar = (optstring[0] == ':') ? ':' : '?';
+                    }
+                } else {
+                    optarg = NULL;
+                }
+            }
+
+            optcursor = NULL;
+        }
+    } else {
+        /* If getopt() encounters an option character that is not contained in
+           optstring, it shall return the question-mark ( '?' ) character. */
+        optchar = '?';
+    }
+
+    if (optcursor == NULL || *++optcursor == '\0') ++optind;
+
+    return optchar;
+
+no_more_optchars:
+    optcursor = NULL;
+    return -1;
+}
+
+/* Implementation based on [1].
+
+[1] http://www.kernel.org/doc/man-pages/online/pages/man3/getopt.3.html
+*/
+int getopt_long(int argc, char* const argv[], const char* optstring,
+                const struct option* longopts, int* longindex) {
+    const struct option* o = longopts;
+    const struct option* match = NULL;
+    int num_matches = 0;
+    size_t argument_name_length = 0;
+    const char* current_argument = NULL;
+    int retval = -1;
+
+    optarg = NULL;
+    optopt = 0;
+
+    if (optind >= argc) return -1;
+
+    if (strlen(argv[optind]) < 3 || strncmp(argv[optind], "--", 2) != 0)
+        return getopt(argc, argv, optstring);
+
+    /* It's an option; starts with -- and is longer than two chars. */
+    current_argument = argv[optind] + 2;
+    argument_name_length = strcspn(current_argument, "=");
+    for (; o->name; ++o) {
+        if (strncmp(o->name, current_argument, argument_name_length) == 0) {
+            match = o;
+            ++num_matches;
+        }
+    }
+
+    if (num_matches == 1) {
+        /* If longindex is not NULL, it points to a variable which is set to the
+           index of the long option relative to longopts. */
+        if (longindex) *longindex = (match - longopts);
+
+        /* If flag is NULL, then getopt_long() shall return val.
+           Otherwise, getopt_long() returns 0, and flag shall point to a
+           variable which shall be set to val if the option is found, but left
+           unchanged if the option is not found. */
+        if (match->flag) *(match->flag) = match->val;
+
+        retval = match->flag ? 0 : match->val;
+
+        if (match->has_arg != no_argument) {
+            optarg = strchr(argv[optind], '=');
+            if (optarg != NULL) ++optarg;
+
+            if (match->has_arg == required_argument) {
+                /* Only scan the next argv for required arguments. Behavior is
+                   not
+                   specified, but has been observed with Ubuntu and Mac OSX. */
+                if (optarg == NULL && ++optind < argc) {
+                    optarg = argv[optind];
+                }
+
+                if (optarg == NULL) retval = ':';
+            }
+        } else if (strchr(argv[optind], '=')) {
+            /* An argument was provided to a non-argument option.
+               I haven't seen this specified explicitly, but both GNU and
+               BSD-based implementations show this behavior.
+            */
+            retval = '?';
+        }
+    } else {
+        /* Unknown option or ambiguous match. */
+        retval = '?';
+    }
+
+    ++optind;
+    return retval;
+}
diff --git a/getopt.h b/getopt.h
new file mode 100644
index 0000000..03f769f
--- /dev/null
+++ b/getopt.h
@@ -0,0 +1,59 @@
+/*******************************************************************************
+ * Copyright (c) 2012-2017, Kim Grasman <kim.grasman@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Kim Grasman nor the
+ *     names of contributors may be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL KIM GRASMAN BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ******************************************************************************/
+
+#ifndef INCLUDED_GETOPT_PORT_H
+#define INCLUDED_GETOPT_PORT_H
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+#define no_argument 1
+#define required_argument 2
+#define optional_argument 3
+
+extern char* optarg;
+extern int   optind, opterr, optopt;
+
+struct option {
+    const char* name;
+    int         has_arg;
+    int*        flag;
+    int         val;
+};
+
+int getopt(int argc, char* const argv[], const char* optstring);
+
+int getopt_long(int argc, char* const argv[], const char* optstring,
+                const struct option* longopts, int* longindex);
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif // INCLUDED_GETOPT_PORT_H
diff --git a/main.cc b/main.cc
new file mode 100644
index 0000000..441dcf3
--- /dev/null
+++ b/main.cc
@@ -0,0 +1,40 @@
+#include <iostream>
+
+#ifdef _MSC_VER
+#include "getopt.h"
+#else
+#include <unistd.h>
+#endif
+
+#include "Driver.hh"
+#include "Log.hh"
+#include "Version.hh"
+
+int main(int argc, char* argv[]) {
+    int rv;
+    pcc::LogLevel level = pcc::PCC_WARNING;
+    while ((rv = getopt(argc, argv, "vVh")) != -1) {
+        switch (rv) {
+        case 'v':
+            level = pcc::PCC_DEBUG;
+            break;
+        case 'V':
+            pcc::ShowVersion();
+        case 'h':
+            pcc::ShowHelp();
+        default:
+            pcc::Log(pcc::PCC_ERROR, "Unknown option \"%c\".", rv);
+            pcc::ShowHelp();
+        }
+    }
+    if (optind >= argc) {
+        pcc::Log(pcc::PCC_ERROR, "No input file specified");
+        return 0;
+    }
+    for (int i = optind; i < argc; i++) {
+        pcc::Context context(argv[i]);
+        pcc::Driver driver(&context);
+        driver.Parse(argv[i]);
+    }
+    return 0;
+}
diff --git a/node/BaseNode.cc b/node/BaseNode.cc
new file mode 100644
index 0000000..98ebb82
--- /dev/null
+++ b/node/BaseNode.cc
@@ -0,0 +1,6 @@
+#include "BaseNode.hh"
+
+namespace pcc {
+BaseNode::BaseNode(Driver* driver)
+    : driver_(driver) {}
+} // namespace pcc
diff --git a/node/BaseNode.hh b/node/BaseNode.hh
new file mode 100644
index 0000000..ae0ccea
--- /dev/null
+++ b/node/BaseNode.hh
@@ -0,0 +1,21 @@
+#ifndef PCC_BASE_H
+#define PCC_BASE_H
+
+#include <llvm/IR/Value.h>
+
+#include "Driver.hh"
+
+namespace pcc {
+using Value = llvm::Value*;
+
+class BaseNode {
+  public:
+    virtual Value CodeGen() = 0;
+    BaseNode(Driver* driver);
+
+  protected:
+    Driver* driver_;
+};
+} // namespace pcc
+
+#endif
diff --git a/node/LiteralNode.cc b/node/LiteralNode.cc
new file mode 100644
index 0000000..57cc65b
--- /dev/null
+++ b/node/LiteralNode.cc
@@ -0,0 +1,22 @@
+#include "LiteralNode.hh"
+
+namespace pcc {
+StringLiteralNode::StringLiteralNode(Driver* driver, char* value)
+    : BaseNode(driver)
+    , value_(value) {}
+
+Value StringLiteralNode::CodeGen() {
+    llvm::Module* module = driver_->GetModule();
+    llvm::LLVMContext& context = module->getContext();
+    llvm::Constant* str = llvm::ConstantDataArray::getString(context, value_);
+    llvm::Type* type = str->getType();
+    llvm::GlobalVariable* var = new llvm::GlobalVariable(
+        *module, type, true, llvm::GlobalVariable::InternalLinkage, str);
+    llvm::Constant* zero =
+        llvm::Constant::getNullValue(llvm::IntegerType::getInt32Ty(context));
+    llvm::Constant* indices[] = {zero, zero};
+    llvm::Constant* ptr =
+        llvm::ConstantExpr::getGetElementPtr(type, var, indices, true);
+    return ptr;
+}
+} // namespace pcc
diff --git a/node/LiteralNode.hh b/node/LiteralNode.hh
new file mode 100644
index 0000000..2e9b43a
--- /dev/null
+++ b/node/LiteralNode.hh
@@ -0,0 +1,17 @@
+#ifndef PCC_LITERALNODE_H
+#define PCC_LITERALNODE_H
+
+#include "BaseNode.hh"
+
+namespace pcc {
+class StringLiteralNode : public BaseNode {
+  public:
+    StringLiteralNode(Driver* driver, char* value);
+    Value CodeGen() override;
+
+  private:
+    char* value_;
+};
+} // namespace pcc
+
+#endif
diff --git a/t/1.pas b/t/1.pas
new file mode 100644
index 0000000..0275bbf
--- /dev/null
+++ b/t/1.pas
@@ -0,0 +1,17 @@
+program a;
+VAR
+    f : integer;
+    g : real;
+    h : boolean;
+    j : integer;
+
+function test(a:integer;b:string):char;
+var s1:real;
+begin
+    f:=b;
+    g:=c;
+    if g<=c then
+    h:=ture
+    else
+    h:=false;
+end;