MultiSource/Applications/kimwitu++/doc/kpp-rpn.xml

<appendix id="app:rpn">
  <title>Complete code of RPN example</title>
  <sect1><title>main.k</title>
    <programlisting>
      <![CDATA[
  %{
  #include <iostream>
  #include "k.h"
  #include "rk.h"
  #include "unpk.h"
  #include "csgiok.h"

  int yyparse( );
  aritherm root_term;
  %}

  %{ KC_TYPES_HEADER
  extern aritherm root_term;
  %}

  %option yystype

  void
  printer( const char *s, uview v ) {
    std::cout << s;
  }

  int
  main( int argc, char** argv ) {
    std::cout << "rpn calculator" << std::endl;
    yyparse( );
    aritherm canon_term = root_term -> rewrite( canonify );
    aritherm simpl_term = canon_term -> rewrite( simplify );
    std::cout << "simplified term in infix notation" << endl;
    simpl_term -> unparse( printer, infix );
    std::cout << std::endl;
  }
      ]]>
    </programlisting>
  </sect1>
  <sect1><title>abstr.k</title>
    <programlisting>
      <![CDATA[
  aritherm:   SimpleTerm  ( simpleterm )
	    | Plus	  ( aritherm aritherm )
	    | Minus	  ( aritherm aritherm )
	    | Mul	  ( aritherm aritherm )
	    | Div	  ( aritherm aritherm );

  simpleterm:   Number	  ( integer )
	      | Ident	  ( casestring );
      ]]>
    </programlisting>
  </sect1>
  <sect1><title>rpn.k</title>
    <programlisting>
      <![CDATA[
  %rview simplify, canonify;

  // 1 + 2 -> 3
  Plus(SimpleTerm(Number(a)),SimpleTerm(Number(b)))->
    <simplify:SimpleTerm(Number(plus(a,b)))>;
  // 1 + 3 + b -> 4 + b
  Plus(SimpleTerm(Number(a)),Plus(SimpleTerm(Number(b)),rem))->
    <simplify:Plus(SimpleTerm(Number(plus(a,b))),rem)>;
  // 1 + 3 - b -> 4 - b
  Plus(SimpleTerm(Number(a)),Minus(SimpleTerm(Number(b)),rem))->
    <simplify:Minus(SimpleTerm(Number(plus(a,b))),rem)>;
  // 6 - 2 -> 4
  Minus(SimpleTerm(Number(a)),SimpleTerm(Number(b)))->
    <simplify:SimpleTerm(Number(minus(a,b)))>;
  // 6 - 4 - b -> 2 - b
  Minus(SimpleTerm(Number(a)),Minus(SimpleTerm(Number(b)),rem))->
    <simplify:Minus(SimpleTerm(Number(minus(a,b))),rem)>;
  // 6 - 4 + b -> 2 + b
  Minus(SimpleTerm(Number(a)),Plus(SimpleTerm(Number(b)),rem))->
    <simplify:Plus(SimpleTerm(Number(minus(a,b))),rem)>;
  // 3 * 2 * b -> 6 * b
  Mul(SimpleTerm(Number(a)),Mul(SimpleTerm(Number(b)),rem))->
    <simplify:Mul(SimpleTerm(Number(mul(a,b))),rem)>;
  // 3 * 2 / b -> 6 / b
  Mul(SimpleTerm(Number(a)),Div(SimpleTerm(Number(b)),rem))->
    <simplify:Div(SimpleTerm(Number(mul(a,b))),rem)>;
  // 3 * 2 -> 6
  Mul(SimpleTerm(Number(a)),SimpleTerm(Number(b)))->
    <simplify:SimpleTerm(Number(mul(a,b)))>;
  // 6 / 2 -> 3
  Div(SimpleTerm(Number(a)),SimpleTerm(Number(b)))->
    <simplify:SimpleTerm(Number(div(a,b)))>;
  // 6 / 2 / b -> 3 / b
  Div(SimpleTerm(Number(a)),Div(SimpleTerm(Number(b)),rem))->
    <simplify:Div(SimpleTerm(Number(div(a,b))),rem)>;
  // 6 / 2 * b -> 3 * b
  Div(SimpleTerm(Number(a)),Mul(SimpleTerm(Number(b)),rem))->
    <simplify:Mul(SimpleTerm(Number(div(a,b))),rem)>;

  // a + a -> 2 * a
  Plus(b=SimpleTerm(Ident(a)),SimpleTerm(Ident(a)))->
    <simplify:Mul(SimpleTerm(Number(mkinteger(2))),b)>;
  // a - a -> 0
  Minus(SimpleTerm(Ident(a)),SimpleTerm(Ident(a)))->
    <simplify: SimpleTerm(Number(mkinteger(0)))>;
  // a / a -> 1
  Div(SimpleTerm(Ident(a)),SimpleTerm(Ident(a)))->
    <simplify: SimpleTerm(Number(mkinteger(1)))>;
  // 6 * a + a -> 7 * a
  Plus(Mul(SimpleTerm(Number(a)),SimpleTerm(Ident(b))),c=SimpleTerm(Ident(b)))->
    <simplify: Mul(SimpleTerm(Number(plus(a,mkinteger(1)))),c)>;
  // 6 * a -a -> 5 * a
  Minus(Mul(SimpleTerm(Number(a)),SimpleTerm(Ident(b))),c=SimpleTerm(Ident(b)))->
    <simplify: Mul(SimpleTerm(Number(minus(a,mkinteger(1)))),c)>;
  // 6 * a + 3 * a -> 9 * a
  Plus(Mul(SimpleTerm(Number(a)),SimpleTerm(Ident(b))),
       Mul(SimpleTerm(Number(d)),c=SimpleTerm(Ident(b))))->
    <simplify: Mul(SimpleTerm(Number(plus(a,d))),c)>;
  // 6 * a - 2 * a -> 4 * a
  Minus(Mul(SimpleTerm(Number(a)),SimpleTerm(Ident(b))),
	Mul(SimpleTerm(Number(d)),c=SimpleTerm(Ident(b))))->
    <simplify: Mul(SimpleTerm(Number(minus(a,d))),c)>;
  // a + (a + 2 * b) -> 2 * a + 2 * b
  Plus(b=SimpleTerm(Ident(a)),Plus(SimpleTerm(Ident(a)),rem))->
    <simplify: Plus(Mul(SimpleTerm(Number(mkinteger(2))),b),rem)>;
      // a - (a +- 2 * b) -> 2 * b
  Minus(SimpleTerm(Ident(a)),Plus(SimpleTerm(Ident(a)),rem)),
  Minus(SimpleTerm(Ident(a)),Minus(SimpleTerm(Ident(a)),rem))->
    <simplify: rem>;
  // a + (a - 2 * b) -> 2 * a - 2 * b
  Plus(b=SimpleTerm(Ident(a)),Minus(SimpleTerm(Ident(a)),rem))->
    <simplify: Minus(Mul(SimpleTerm(Number(mkinteger(2))),b),rem)>;

  // (a + b) + c -> a + (b + c)
  Plus( Plus(a, b), c)
	  -> < canonify: Plus(a, Plus(b, c))>;
  // (a - b) + c -> c + (a - b)
  Plus( Minus(a, b), c)
	  -> < canonify: Plus(c, Minus(a, b))>;
  // (a + b) - c -> a + (b - c)
  Minus( Plus(a, b), c)
	  -> < canonify: Plus(a, Minus(b, c))>;
  // (a * b) * c -> a * (b * c)
  Mul( Mul(a, b), c)
	  -> < canonify: Mul(a, Mul(b, c))>;
  // a + 5 -> 5 + a
  Plus( a=SimpleTerm(Ident(*)), b=SimpleTerm(Number(*)) )
	  -> < canonify: Plus(b, a)>;
  // a * 5 -> 5 * a
  Mul( a=SimpleTerm(Ident(*)), b=SimpleTerm(Number(*)) )
	  -> < canonify: Mul(b, a)>;
  // a + (6 + b) -> 6 + (a + b)
  Plus( a=SimpleTerm(Ident(*)), Plus(b=SimpleTerm(Number(*)), rest) )
	  -> < canonify: Plus(b, Plus(a,rest))>;
  // a * (6 * b) -> 6 * (a * b)
  Mul( a=SimpleTerm(Ident(*)), Mul(b=SimpleTerm(Number(*)), rest) )
	  -> < canonify: Mul(b, Mul(a,rest))>;

  %{ KC_REWRITE
  inline integer plus(integer a, integer b){
    return mkinteger(a->value+b->value);
  }
  inline integer minus(integer a, integer b){
    return mkinteger(a->value-b->value);
  }
  inline integer mul(integer a, integer b){
    return mkinteger(a->value*b->value);
  }
  inline integer div(integer a, integer b){
    return mkinteger(b->value==0 ? 0 : a->value / b->value);
  }
  %}

  %uview infix,postfix;

  Plus(a,b)->[infix: "(" a "+" b ")"];
  Minus(a,b)->[infix: "(" a "-" b ")"];
  Mul(a,b)->[infix: "(" a "*" b ")"];
  Div(a,b)->[infix: "(" a "/" b ")"];
      ]]>
    </programlisting>
  </sect1>
  <sect1><title>lexic.l</title>
    <programlisting>
      <![CDATA[
  %{
  #include <iostream>
  #include "k.h"
  #include "yystype.h"
  #include "syntax.h"
  #include "rpn.h"
  %}

  %option noyywrap

  %%

  -?[0-9]+    { yylval.yt_integer = mkinteger(atoi(yytext)); return NUMBER;}
  [a-z]+      { yylval.yt_casestring = mkcasestring(yytext); return IDENT; }
  [+*-/]      { return yytext[0]; }
  [\t ]+      { /*empty*/ }
  \n          { return EOF; }
  .           { std::cerr << "Unkown character: " << yytext[0] << std::endl; }

  %%

  extern void yyerror(const char *s) {
    std::cerr << "Syntax error: " << s << std::endl;
  }

      ]]>
    </programlisting>
  </sect1>
  <sect1><title>syntax.y</title>
    <programlisting>
      <![CDATA[
  %{
  #include "k.h"
  #include "yystype.h"

  extern void yyerror(const char*);
  extern int yylex();
  %}

  %token <yt_integer> NUMBER
  %token <yt_casestring> IDENT
  %token NEWLINE

  %type <yt_aritherm> aritherm
  %type <yt_simpleterm> simpleterm

  %%


  aritherm:
	  simpleterm
	  { root_term = $$ = SimpleTerm($1); }
	  | aritherm aritherm '+'
	  { root_term = $$ = Plus($1,$2); }
	  | aritherm aritherm '*'
	  { root_term = $$ = Mul($1,$2); }
	  | aritherm aritherm '-'
	  { root_term = $$ = Minus($1,$2); }
	  | aritherm aritherm '/'
	  { root_term = $$ = Div($1,$2); }
  ;

  simpleterm:
	  NUMBER
	  { $$ = Number($1); }
	  | IDENT
	  { $$ = Ident($1); }
  ;
      ]]>
    </programlisting>
  </sect1>
  <sect1 id="app:make"><title>Makefile</title>
    <programlisting>
      <![CDATA[
# Reverse Polish Notation, Makefile
# c 2001, Michael Piefel <piefel@informatik.hu-berlin.de>
 
.PRECIOUS: lexic.c y.output

# Tools
SHELL    = /bin/sh
YACC     = bison
LEX      = flex
CC       = ${CXX}
KC       = kc++

#Flages
YFLAGS   = -d -y
LFLAGS   = -t
CXXFLAGS = -g -Wall -Wno-unused -DYYDEBUG -DYYERROR_VERBOSE
CFLAGS   = ${CXXFLAGS}

# Sources
KFILES   = rpn.k main.k abstr.k
YFILES   = syntax.y
LFILES   = lexic.l


# Goals
PARSER  = rpn-parser  

# Help files

KC_TIME = .kc_time_stamp

KC_OGEN = k.o csgiok.o unpk.o rk.o
KC_OSRC = $(KFILES:.k=.o)
OBJS    = $(KC_OGEN) $(KC_OSRC) $(YFILES:.y=.o) $(LFILES:.l=.o) $(CFILES:.cc=.o)


# default rule
$(PARSER)::

# include or make autodependencies
ifeq (.depend,$(wildcard .depend))
include .depend
else
$(PARSER):: depend
endif

# Rules
$(KC_TIME): $(KFILES)
	$(KC) $(KFILES)
	touch $(KC_TIME)

$(PARSER):: $(KC_TIME) $(OBJS)
	$(CXX) $(CFLAGS) $(OBJS) ${LIBS} -o $@


syntax.h : y.tab.h
	-cmp -s syntax.h y.tab.h || cp y.tab.h syntax.h

y.tab.h : syntax.c

depend dep:
	@echo Make dependencies first
	$(MAKE) $(KC_TIME)
	$(MAKE) $(YFILES:.y=.c)
	$(MAKE) $(LFILES:.l=.c)
	$(MAKE) syntax.h
	$(CC) -M *.cc > .depend
  
clean:
	-rm -f $(OBJS) core *~ *.bak  $(KFILES:.k=.cc)  $(KC_OGEN:.o=.cc) $(KC_TIME) .kc* \
        $(YFILES:.y=.c) $(LFILES:.l=.c) $(KC_OGEN:.o=.h) $(KFILES:.k=.h) out.* \
        y.tab.h syntax.h syntax.output syntax.tab.c yystype.h
      ]]>
    </programlisting>
  </sect1>
</appendix>