commit 846b7824934be136b3d770e1d63fcda4b30e5ad5
Author: pjht <pjht@users.noreply.github.com>
Date:   Fri Jul 20 19:44:57 2018 -0500

    Initial Commit

diff --git a/backend.rb b/backend.rb
new file mode 100644
index 0000000..88ebbda
--- /dev/null
+++ b/backend.rb
@@ -0,0 +1,16 @@
+class Backend
+  attr_writer :dbg
+  def initialize(code)
+    @code=code
+    @dbg=false
+    @pc=0
+  end
+  def run
+    while true
+      op=@code[@pc]
+      break if op==nil
+      inc=execute(op)
+      @pc+=1 if inc
+    end
+  end
+end
diff --git a/compiler.rb b/compiler.rb
new file mode 100644
index 0000000..902b5bf
--- /dev/null
+++ b/compiler.rb
@@ -0,0 +1,16 @@
+require_relative "parser.rb"
+require_relative "interpreter.rb"
+require_relative "copyprop.rb"
+require_relative "deadopt.rb"
+if ARGV[0]!=nil
+  parser=Parser.new(File.read(ARGV[0]))
+else
+  parser=Parser.new(File.read("prg.lang"))
+end
+parser.parse
+opt=CopyProp.new(parser.output)
+opt=DeadOpt.new(opt.optimize)
+out=opt.optimize
+p out
+interp=Interpreter.new(out)
+interp.run
diff --git a/console b/console
new file mode 100755
index 0000000..f38cda1
--- /dev/null
+++ b/console
@@ -0,0 +1,4 @@
+#!/usr/bin/env ruby
+require "pry"
+require_relative "parser.rb"
+Pry.start()
diff --git a/copyprop.rb b/copyprop.rb
new file mode 100644
index 0000000..9a627aa
--- /dev/null
+++ b/copyprop.rb
@@ -0,0 +1,32 @@
+class CopyProp
+  def initialize(code)
+    @code=code
+  end
+  def optimize()
+    table={}
+    i=0
+    @code.clone.each do |quad|
+      if quad[3]==nil and quad[1]=="="
+        table[quad[0]]=quad[2]
+      else
+        if table.has_key? quad[2]
+          while true
+            replace=table[quad[2]]
+            break if replace==nil
+            quad[2]=replace
+          end
+        end
+        if table.has_key? quad[3]
+          while true
+            replace=table[quad[3]]
+            break if replace==nil
+            quad[3]=replace
+          end
+        end
+      end
+      @code[i]=quad
+      i+=1
+    end
+    return @code
+  end
+end
diff --git a/deadopt.rb b/deadopt.rb
new file mode 100644
index 0000000..ddf60de
--- /dev/null
+++ b/deadopt.rb
@@ -0,0 +1,49 @@
+require "set"
+class DeadOpt
+  def initialize(code)
+    @code=code
+    @always=["call","func"]
+    @ignore=["call","func"]
+  end
+  def optimize()
+    optimized=false
+    while true
+      table=Set.new
+      @code.each do |quad|
+        next if @ignore.include? quad[1]
+        if quad[2]
+          table.add quad[2] if quad[2].is_a? String
+        end
+        if quad[3]
+          table.add quad[3] if quad[2].is_a? String
+        end
+      end
+      dupcode=@code.clone
+      @code=[]
+      dupcode.each do |quad|
+        if @always.include? quad[1]
+          if quad[0]
+            if !(table.include? quad[0])
+              quad[0]=nil
+              optimized=true
+            end
+          end
+          @code.push quad
+        else
+          if quad[0]
+            if table.include? quad[0]
+              @code.push quad
+            else
+              optimized=true
+            end
+          else
+            @code.push quad
+          end
+        end
+      end
+      break if optimized==false
+      optimized=false
+    end
+    return @code
+  end
+end
diff --git a/grammar.txt b/grammar.txt
new file mode 100644
index 0000000..6db4401
--- /dev/null
+++ b/grammar.txt
@@ -0,0 +1,35 @@
+tokens:
+\s+ # Do nothing
+( OPEN_PAREN
+) CLOSE_PAREN
+{ OPEN_CURL
+} CLOSE_CURL
++ ADD
+- SUB
+* MUL
+/ DIV
+= EQUALS
+, COMMA
+; SEMICOLON
+"[^"]*" STRING
+def DEF
+return RETURN
+\d+ NUMBER
+\w+ IDENT
+grammar:
+program: block
+block: { statement }
+statement: IDENT EQUALS expression SEMICOLON # ident=expression; : x=10;
+| DEF IDENT OPEN_CURL block CLOSE_CURL # def ident { block } : def hi{return 10}
+| RETURN expression SEMICOLON # return expression; : return 10;
+| expression SEMICOLON # expression; : 1+2;
+expression: term { addop term } # 1+2-3+400-67...
+term: factor { mulop factor } # 7*3*67/4*8*3...
+factor: IDENT OPEN_PAREN CLOSE_PAREN # ident() : hi()
+| IDENT # ident : hi
+| OPEN_PAREN expression CLOSE_PAREN # (expression): (1+2)
+| SUB NUMBER # -number : -10
+| NUMBER # number : 10
+| STRING # string : "hi"
+addop: ADD | SUB
+mulop: MUL | DIV
diff --git a/interpreter.rb b/interpreter.rb
new file mode 100644
index 0000000..b780a6f
--- /dev/null
+++ b/interpreter.rb
@@ -0,0 +1,83 @@
+require_relative "backend.rb"
+class Interpreter < Backend
+  def initialize(code)
+    @vartable={}
+    @paramtable=[]
+    @functable={}
+    @retstack=[]
+    @envstack=[]
+    @noinc=["call","return"]
+    @infunc=false
+    super(code)
+  end
+  def execute(op)
+    if @infunc
+      if op[1]=="funcend"
+        @infunc=false
+      end
+      return true
+    end
+    puts "Running #{op}"
+    case op[1]
+    when "="
+      @vartable[op[0]]=toval(op[2])
+    when "+","-","*","/"
+      op[2]=toval(op[2])
+      op[3]=toval(op[3])
+      @vartable[op[0]]=op[2].send(op[1],op[3])
+    when "param"
+      @paramtable.push toval(op[2])
+    when "call"
+      result=nil
+      case op[2]
+      when "puts"
+        puts @paramtable.shift
+        result=1
+        @pc+=1
+      when "gets"
+        print "Enter number:"
+        result=gets.chomp!.to_i
+        @pc+=1
+      else
+        if @functable.has_key? op[2]
+          @retstack.push([@pc+1,op[0]])
+          @pc=@functable[op[2]]
+          @envstack.push @vartable
+          @vartable={}
+        end
+      end
+      if result and op[0]
+        @vartable[op[0]]=result
+      end
+    when "func"
+      @functable[op[2]]=@pc+1
+      @infunc=true
+    when "return"
+      info=@retstack.pop()
+      @pc=info[0]
+      if op[2]
+        rval=toval(op[2])
+      else
+        rval=nil
+      end
+      @vartable=@envstack.pop()
+      @vartable[info[1]]=rval
+    end
+    puts "Vars:#{@vartable}"
+    puts "Params:#{@paramtable}"
+    puts "Funcs:#{@functable}"
+    return !(@noinc.include? op[1])
+  end
+  private
+  def toval(obj)
+    if obj.is_a? Integer
+      return obj
+    elsif /^\d+/.match obj
+      return obj.to_i
+    elsif /^"([^"]+)"/.match obj
+      return $1
+    else
+      return @vartable[obj]
+    end
+  end
+end
diff --git a/lexer.rb b/lexer.rb
new file mode 100644
index 0000000..01050d9
--- /dev/null
+++ b/lexer.rb
@@ -0,0 +1,69 @@
+require "strscan"
+require_relative "token.rb"
+class Lexer
+  def initialize(string)
+    @scan=StringScanner.new(string)
+    @line=0
+  end
+  def next_token()
+    return nil if @scan.eos?
+    lexeme=@scan.scan(/\n/)
+    if lexeme
+      @line+=1
+      return next_token
+    end
+    lexeme=@scan.scan(/\s+/)
+    return next_token if lexeme
+    lexeme=@scan.scan(/\(/)
+    return Token.new(:OPEN_PAREN) if lexeme
+    lexeme=@scan.scan(/\)/)
+    return Token.new(:CLOSE_PAREN) if lexeme
+    lexeme=@scan.scan(/\{/)
+    return Token.new(:OPEN_CURL) if lexeme
+    lexeme=@scan.scan(/\}/)
+    return Token.new(:CLOSE_CURL) if lexeme
+    lexeme=@scan.scan(/\+/)
+    return Token.new(:ADD) if lexeme
+    lexeme=@scan.scan(/\-/)
+    return Token.new(:SUB) if lexeme
+    lexeme=@scan.scan(/\*/)
+    return Token.new(:MUL) if lexeme
+    lexeme=@scan.scan(/\//)
+    return Token.new(:DIV) if lexeme
+    lexeme=@scan.scan(/=/)
+    return Token.new(:EQUALS) if lexeme
+    lexeme=@scan.scan(/,/)
+    return Token.new(:COMMA) if lexeme
+    lexeme=@scan.scan(/;/)
+    return Token.new(:SEMICOLON) if lexeme
+    lexeme=@scan.scan(/"/)
+    return string() if lexeme
+    lexeme=@scan.scan(/def/)
+    return Token.new(:DEF) if lexeme
+    lexeme=@scan.scan(/return/)
+    return Token.new(:RETURN) if lexeme
+    lexeme=@scan.scan(/\d+/)
+    return Number.new(lexeme) if lexeme
+    lexeme=@scan.scan(/\w+/)
+    return Ident.new(lexeme) if lexeme
+    puts "Error: Cannot match #{@scan.rest}"
+    exit
+  end
+  def tokenize()
+    prg=[]
+    while true
+      token=next_token
+      return prg if token==nil
+      prg.push token
+    end
+  end
+  private
+  def string()
+    lexeme=@scan.scan(/\[^"]*/)
+    ok=@scan.scan(/"/)
+    if ok==nil
+      puts "Error: Unterminated string \"#{lexeme} on line #{@line}"
+    end
+    return StrTok.new('"'+lexeme+'"')
+  end
+end
diff --git a/parser.rb b/parser.rb
new file mode 100644
index 0000000..b4855ea
--- /dev/null
+++ b/parser.rb
@@ -0,0 +1,189 @@
+require_relative "lexer.rb"
+require_relative "token.rb"
+require "pry"
+class Parser
+  @@tag_to_op={:ADD=>"+",:SUB=>"-",:MUL=>"*",:DIV=>"/"}
+  attr_reader :output
+  def initialize(string)
+    @debug=false
+    @tokens=Lexer.new(string).tokenize
+    p @tokens if @debug
+    @token=@tokens.shift
+    @tmpid=1
+    @output=[]
+  end
+  def parse()
+    block()
+    expected("EOF") if @token != nil
+  end
+  private
+  def expected(str)
+    puts "Error: #{str} Expected"
+    begin
+      raise StandardError
+    rescue StandardError => e
+      e.backtrace.shift
+      puts e.backtrace
+    end
+    exit
+  end
+  def get_numb()
+    expected("Number") if @token.class!=Number
+    tok=@token
+    @token=@tokens.shift
+    p tok if @debug
+    p [@token,@tokens].flatten if @debug
+    return tok.val
+  end
+  def get_name()
+    expected("Name") if @token.class!=Ident
+    tok=@token
+    @token=@tokens.shift
+    p tok if @debug
+    p [@token,@tokens].flatten if @debug
+    return tok.val
+  end
+  def get_str()
+    expected("String") if @token.class!=StrTok
+    tok=@token
+    @token=@tokens.shift
+    p tok if @debug
+    p [@token,@tokens].flatten if @debug
+    return tok.strval
+  end
+  def match(tag)
+    expected(tag) if @token==nil
+    expected(tag) if @token.tag!=tag
+    @token=@tokens.shift
+    p tok if @debug
+    p [@token,@tokens].flatten if @debug
+  end
+  def make_tmp()
+    tmp="t#{@tmpid}"
+    @tmpid+=1
+    return tmp
+  end
+  def factor()
+    case @token.tag
+    when :IDENT
+      name=get_name()
+      tmp=make_tmp()
+      if @token.tag==:OPEN_PAREN
+        params=[]
+        match(:OPEN_PAREN)
+        while true
+          break if @token.tag==:CLOSE_PAREN
+          params.push expression()
+          break if @token.tag!=:COMMA
+          match(:COMMA)
+        end
+        match(:CLOSE_PAREN)
+        params.each do |tmpvar|
+          @output.push [nil,"param",tmpvar,nil]
+        end
+        @output.push [tmp,"call",name,nil]
+      else
+        @output.push [tmp,"=",name,nil]
+      end
+    when :OPEN_PAREN
+      match(:OPEN_PAREN)
+      tmp=expression()
+      match(:CLOSE_PAREN)
+    when :SUB
+      match(:SUB)
+      tmp=make_tmp()
+      num=get_numb()
+      @output.push [tmp,"=","-#{num}",nil]
+    else
+      tmp=make_tmp()
+      if @token.class==StrTok
+        val=get_str()
+      else
+        val=get_numb()
+      end
+      @output.push [tmp,"=",val,nil]
+    end
+    return tmp
+  end
+  def term()
+    ops=[:MUL,:DIV]
+    tmp=factor()
+    oldtmp=tmp
+    return tmp if @token==nil
+    while ops.include? @token.tag
+      tmp=make_tmp()
+      op=@token.tag
+      match(op)
+      op=@@tag_to_op[op]
+      fact=factor()
+      @output.push [tmp,op,oldtmp,fact]
+      oldtmp=tmp
+      break if @token==nil
+    end
+    return tmp
+  end
+  def expression()
+    ops=[:ADD,:SUB]
+    tmp=term()
+    oldtmp=tmp
+    return tmp if @token==nil
+    while ops.include? @token.tag
+      tmp=make_tmp()
+      op=@token.tag
+      match(op)
+      op=@@tag_to_op[op]
+      trm=term()
+      @output.push [tmp,op,oldtmp,trm]
+      oldtmp=tmp
+      break if @token==nil
+    end
+    return tmp
+  end
+  def assingment()
+    name=get_name()
+    match(:EQUALS)
+    tmpvar=expression()
+    @output.push [name,"=",tmpvar,nil]
+  end
+  def func()
+    match(:DEF)
+    name=@token.val
+    match(:IDENT)
+    match(:OPEN_CURL)
+    @output.push [nil,"func",name,nil]
+    block(:CLOSE_CURL)
+    @output.push [nil,"return",nil,nil]
+    @output.push [nil,"funcend",nil,nil]
+  end
+  def ret()
+    match(:RETURN)
+    tmpvar=expression()
+    @output.push [nil,"return",tmpvar,nil]
+  end
+  def statement()
+    if @token.tag==:IDENT and @tokens[0].tag==:EQUALS
+      assingment()
+      match(:SEMICOLON)
+    elsif @token.tag==:DEF
+      func()
+    elsif @token.tag==:RETURN
+      ret()
+      match(:SEMICOLON)
+    else
+      expression()
+      match(:SEMICOLON)
+    end
+  end
+  def block(end_tok=nil)
+    if end_tok
+      while @token.tag!=end_tok
+        statement()
+      end
+      match(end_tok)
+    else
+      while @token!=nil
+        statement()
+      end
+    end
+  end
+end
diff --git a/prg.lang b/prg.lang
new file mode 100644
index 0000000..682fafb
--- /dev/null
+++ b/prg.lang
@@ -0,0 +1,9 @@
+def hi {
+  x=10;
+  puts(x);
+  return x;
+}
+x=15;
+y=hi();
+puts(x);
+puts(y);
diff --git a/token.rb b/token.rb
new file mode 100644
index 0000000..58737cd
--- /dev/null
+++ b/token.rb
@@ -0,0 +1,30 @@
+class Token
+  attr_reader :tag
+  def initialize(tag)
+    @tag=tag
+  end
+end
+
+class Number < Token
+  attr_reader :val
+  def initialize(lexeme)
+    super(:NUMB)
+    @val=lexeme.to_i
+  end
+end
+
+class Ident < Token
+  attr_reader :val
+  def initialize(lexeme)
+    super(:IDENT)
+    @val=lexeme
+  end
+end
+
+class StrTok < Token
+  attr_reader :strval
+  def initialize(lexeme)
+    super(:STRING)
+    @strval=lexeme
+  end
+end