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researchv10 Norman

type Lineno = int
val lineno = ref 1
fun error s l = output std_out 
	("line " ^ makestring (l:int) ^ ":" ^ s ^ "\n")
fun lookup s = ordof(s,0) - ord("a")+1
%%
%structure Calc
%eof   EOF
%start START

%left SUB PLUS
%left TIMES DIV

%right CARAT

%term ID of string | NUM of int | PLUS | TIMES | PRINT | EOS | EOF |
	CARAT | DIV | SUB
%nonterm EXP of int | START | STMT | STMT_LIST

%%
  START : STMT_LIST	()
  STMT_LIST : STMT_LIST STMT EOS ()
  STMT_LIST : ()
  STMT : PRINT EXP 	(print EXP; print "\n"; flush_out std_out)
  STMT : EXP 		()
  EXP : NUM		(NUM)
      | ID		(lookup ID)
      | EXP PLUS EXP	(EXP1+EXP2)
      | EXP TIMES EXP	(EXP1*EXP2)
      | EXP DIV EXP	(EXP1 div EXP2)
      | EXP SUB EXP 	(EXP1-EXP2)
      | EXP CARAT EXP   (let fun e (m,0) = 1
				| e (m,i) = m*e(m,i-1)
			 in e (EXP1,EXP2)	
			 end)

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